Ultraschall Med 2021; 42(04): 367-378
DOI: 10.1055/a-1248-8896
Guidelines & Recommendations

Screening, Management and Delivery in Twin Pregnancy

Artikel in mehreren Sprachen: English | deutsch
Constantin von Kaisenberg*
1   Obstetrics and Gynecology, Hannover Medical School, Hannover, Germany
,
Philipp Klaritsch*
2   Department of Obstetrics and Gynecology, Medical University Graz, Austria
,
Nicole Ochsenbein-Kölble
3   Department of Obstetrics, University Hospital Zürich, Zürich, Switzerland
,
Markus Eugen Hodel
4   Obstetrics, Luzerner Kantonsspital, Lucerne, Switzerland
,
Monika Nothacker
5   AWMF-Institut für Medizinisches Wissensmanagement (AWMF-IMWi), University of Marburg, Germany
,
Kurt Hecher
6   Department of Obstetrics and Fetal Medicine, University Hospital Hamburg-Eppendorf, Hamburg, Germany
› Institutsangaben
Gefördert durch: Deutsche Stiftung Frauengesundheit
Gefördert durch: Deutsche Gesellschaft für Gynäkologie und Geburtshilfe (DGGG)
Gefördert durch: Deutsche Gesellschaft für Ultraschall in der Medizin (DEGUM)
 

Abstract

The following AWMF guideline (DGGG/AGG & DEGUM responsible) deals with the diagnosis, screening and management of twins as well as the timing and mode of birth.

Twin pregnancies can be classified as dichorionic diamniotic (DC DA), monochorionic diamniotic (MC DA) and monochorionic monoamniotic (MC MA) which are always monochorionic.

Twin pregnancies can be concordant (both twins are affected) or discordant (only one twin is affected) for chromosomal defects, malformations, growth restriction and hemodynamic disorders.

Chorionicity is the prognostically most significant parameter. Monochorial twins have significantly higher risks of intrauterine morbidity and mortality compared to dichorial twins.

In particular, general aspects of twin pregnancies such as dating, determination of chorionicity and amnionicity, the labeling of twin fetuses and the perinatal switch phenomenon are discussed.

Routine monitoring of MC and DC twin pregnancies with ultrasound at 11–13+ 6 weeks of gestation for chromosomal defects, invasive prenatal diagnosis, first-trimester NT or CRL discrepancies, early diagnosis of fetal anatomical defects, and management of twins with abnormalities, including selective fetocide, is described.

Second trimester screening and management for preterm birth, intrauterine selective growth restriction (sFGR), classification of monochorial twins with sFGR, and management of the surviving twin after the death of the co-twin are described.

Complications exclusively affecting MC twins include Twin to Twin Transfusion Syndrome (TTTS) with the important topics screening, prognosis, complications of laser therapy, timing of delivery, risks for brain abnormalities and delayed neurological development, Twin Anemia-Polycythemia Sequence (TAPS) and Twin Reversed Arterial Perfusion (TRAP) Sequence. This also includes MC MA twins as well as conjoined twins.

Finally, the birth mode and time for DC and MC twin pregnancies are described.

The information is summarized in 62 recommendations for action, 4 tables and 8 illustrations with comprehensive background texts.

The guideline is an international guideline adaptation (ISUOG, NICE) as well as a systematic literature search and is up-to-date.


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Introduction

Issues and Objectives, Identification and Evaluation of the Evidence

Recommendations

This is a brief version of the AWMF S2e guideline “Monitoring and Management of Twin Pregnancies” (https://www.awmf.org/leitlinien/detail/ll/015-087.html).

The AWMF guideline is an adaptation of the ISUOG and NICE guidelines [1] [2] [3] as well as systematic literature research. It was written to create a very condensed readable practical version and to make the guideline known.

Twin pregnancies can be classified as dichorionic diamniotic (DC DA), monochorionic diamniotic (MC DA) and monochorionic monoamniotic (MC MA).

Twin pregnancies can be concordant (both twins are affected) or discordant (only one twin is affected) for chromosomal defects, malformations, growth restriction and hemodynamic disorders.

Chorionicity is the prognostically most significant parameter. MC twins have significantly higher risks of intrauterine morbidity and mortality than DC twins.


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General Information regarding Twin Pregnancies

Dating of Twin Pregnancies

  • The gestational age of twin pregnancies should be determined at a crown-rump length (CRL) of 45–84 mm (11+ 0 to 13+ 6 weeks of gestation) [4].

  • For spontaneously conceived twins, the larger CRL should be used to estimate the gestational age [5].

  • Twin pregnancies conceived after in vitro fertilization should be determined based on the date of egg collection – or the age of the embryo (in days) at implantation [4].


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Determination of Chorionicity and Amnionicity of Twin Pregnancies

Prior to 13+ 6 weeks of gestation, chorionicity should be determined by

  • assessment of the membrane thickness at the site of insertion of the amniotic membrane into the placenta,

  • idetermination of the T-sign or lambda sign,

  • as well as the number of placenta masses.

An ultrasound image showing chorionicity should be archived in the records for future reference [2] [6].

  • The second opinion of a specialized center should be obtained if it is not possible to determine chorionicity in a routine setting by transabdominal or transvaginal ultrasound.

  • If the determination of chorionicity is also not possible there, the pregnancy should be treated as an MC pregnancy [2].

  • Amnionicity should also be determined and documented when chorionicity is established.

  • MC MA pregnancies should be referred to a specialized center with related management experience [1] ([Fig. 1]).

Zoom Image
Fig. 1 First-trimester ultrasound images of: a dichorionic diamniotic twin pregnancy, in which the twins are separated by a thick layer of fused chorionic membranes, and b a monochorionic diamniotic twin pregnancy in which the twins are separated only by two thin amniotic membranes. Source: Arbeitsgemeinschaft der Wissenschaftlichen Medizinischen Fachgesellschaften e.V (AWMF). Leitlinie zur Überwachung und Betreuung von Zwillingsschwangerschaften. Online: https://www.awmf.org/leitlinien/detail/ll/015-087.html; Stand: 05.10.2020. [rerif]

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Twin Fetus Labeling

  • The labeling of twin fetuses should follow a reliable and uniform strategy and be clearly documented (maternity log, patient documentation).

  • Several parameters should be used for this (e. g. which is to the front, the side, the position, the location of the placenta and umbilical insertion, and the sex) [3] [7].


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The Perinatal Switch Phenomenon

Not all clearly labeled fetuses are actually delivered in that order (switch phenomenon).


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Routine Monitoring of Twin Pregnancies using Ultrasound

  • In any general ultrasound examination of twins, the following parameters should be assessed in both twins with 20 weeks or more of gestational age:

    • biometry, estimated weight and difference of estimated fetal weights (%), amniotic fluid volume (deepest vertical pocket, DVP) and umbilical artery Doppler.

    • An estimated weight difference ≥ 25 % indicates selective fetal growth restriction, sFGR, for which referral to a specialized center is indicated [8].

  • Uncomplicated twin pregnancies should receive first-trimester screening, a detailed second-trimester malformation ultrasound (organ screening), and subsequently serial growth measurements and Doppler ultrasound examinations every 4 weeks.

  • Complicated DC twins should be examined more often, depending on the circumstances and their severity [3].

  • Uncomplicated MC twin pregnancies should receive first-trimester screening and a detailed second-trimester malformation ultrasound (organ screening) and, from 16 weeks of gestation onwards, examined serially every 2 weeks with growth measurements, amniotic fluid volume determination (DVP) and Doppler ultrasound.

  • Depending on the circumstances and their severity complicated MC twins should be examined more frequently [3] [9] [10] ([Fig. 2], [3]).

Zoom Image
Fig. 2 Algorithm of ultrasound monitoring (completed weeks of pregnancy) for uncomplicated dichorial twin pregnancies. Source: Arbeitsgemeinschaft der Wissenschaftlichen Medizinischen Fachgesellschaften e.V (AWMF). Leitlinie zur Überwachung und Betreuung von Zwillingsschwangerschaften. Online: https://www.awmf.org/leitlinien/detail/ll/015-087.html; Stand: 05.10.2020. [rerif]
Zoom Image
Fig. 3 Algorithm of ultrasound monitoring (completed weeks of pregnancy) for uncomplicated monochorionic twin pregnancies. DVP: deepest vertical pocket; PI: pulsatility index; MCA-PSV: peak systolic velocity (Vmax of middle cerebral artery); A. umb: umbilical artery; MCA: middle cerebral artery; EFW: estimated fetal weight. Source: Arbeitsgemeinschaft der Wissenschaftlichen Medizinischen Fachgesellschaften e.V (AWMF). Leitlinie zur Überwachung und Betreuung von Zwillingsschwangerschaften. Online: https://www.awmf.org/leitlinien/detail/ll/015-087.html; Stand: 05.10.2020. [rerif]

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Screening for Chromosomal Abnormalities in Twin Pregnancy

  • First-trimester screening for chromosomal abnormalities in twins should include maternal age, nuchal translucency (NT) and serum biochemistry (free beta-hCG and PAPP-A).

  • If necessary, it should be combined with sonographic markers for chromosomal defects such as the nasal bone, tricuspid regurgitation and ductus venosus (NB, TR, DV) [2] [11] [12] [13].

  • In the case of a “vanishing twin”, first-trimester screening for fetal trisomy should take into account maternal age, fetal NT measurement and serum beta-hCG (without PAPP-A) level.

  • PAPP-A should only be used if it has been adjusted for the interval between the estimated gestational age at fetal death and blood collection [14].

  • First-trimester screening for chromosomal defects in twins may include cell-free fetal (placental) DNA.

  • However, the detection rates of the non-invasive prenatal test (NIPT) for chromosomal defects in twins are lower than for single pregnancies [2] [15].

  • Ultrasound between 11–13+ 6 weeks of pregnancy should include early structured malformation diagnosis including NT [16] [17].

  • Twins are more likely to have an increased risk of chromosomal abnormalities after first-trimester screening (combined test) than singletons.


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Invasive prenatal Diagnosis in Twin Pregnancy

  • The abortion rate after invasive diagnostics is about 2–3.8 % for CVS and 1.5–3.1 % for AC [18] [19] [20] [21].

  • Screening and invasive diagnostic procedures are more complex for twins compared to singletons;

  • therefore such procedures should be performed by experienced physicians.

  • The consultation should include the risks of puncture, possible discordance for aneuploidy, potential management strategies and the risks of embryo reduction or selective fetocide [1] [3].

  • CVS should be the preferred method for DC twins as it can be employed earlier than amniocentesis.

  • Early diagnosis of aneuploidy is particularly important in twin pregnancies, as the risk of selective fetocide is lower in the first trimester than in the second [22].

  • The localization of the fetuses and placentas should be carefully mapped in order to allow clear assignment.

  • DC twins should be sampled individually.

  • If MC twins are also sampled separately, a heterokaryotype can be detected in the case of discordant chromosomal defects (e. g. for trisomies 21, 18, 13, Turner syndrome and triploidy described above).


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Implications of NT or CRL Discordance in the first Trimester

  • The management of twin pregnancies with NT discordance ≥ 20 % or CRL discordance ≥ 10 % between 11–13+ 6 of gestation should be discussed with experts in fetal medicine [23] [24].


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Ultrasound Screening for structural Anomalies in Twin Pregnancy

  • Twin fetuses are to be examined for the presence of severe malformations during first-trimester ultrasound.

  • Organ screening should be performed at about 20 (18–22) weeks of gestation [2] [17] [25], including fetal echocardiography [26] [27].


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Management of Twin Pregnancy discordant for Fetal Anomaly

  • Twin pregnancies discordant for fetal anomaly should be referred to a fetal medicine center [2].


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Selective Fetocide in Twin Pregnancy

  • In the case of anomalies in a discordant DC twin pregnancy, embryo reduction can be performed, preferably in the first trimester, by ultrasound-guided intracardiac injection of potassium chloride or lidocaine [22].

  • When the diagnosis is made in the second trimester, women might opt for late selective termination in the third trimester, if If legally possible, in order not to endanger the survivor in case of preterm birth [1].

  • Selective fetocide in monochorionic twins is performed by cord occlusion, intrafetal laser ablation or radiofrequency ablation [1] [2] [22] [28] [29] [30].


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Screening for Risk of Preterm Birth in Twin Pregnancy

  • Ultrasound cervical length measurement is the preferred screening method for preterm birth of twins;

  • a cervix length of < 25 cm in the second trimester should be used as a cut-off [1] [31].


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Fetal Growth Restriction

Fetal Growth Restriction (FGR, Intrauterine Growth Restriction, IUGR) in twins is found in both MC and DC twins.

Complications frequently affecting MC twins with FGR are Twin to Twin Transfusion Syndrome (TTTS), Twin Reversed Arterial Perfusion Sequence (TRAP) and Twin Anemia Polycythemia Sequence (TAPS).


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Screening, Diagnosis and Management of Fetal Growth Restriction

Diagnostic Criteria and Investigations for selective Fetal Growth Restriction (sFGR)

  • A single estimated weight < 3 rd percentile in a twin, independent of chorionicity defines sFGR.

  • At least 2 of the following 4 parameters must be met for MC twins (fetal weight of one fetus < 10th percentile, abdominal circumference < 10th percentile, EFW difference ≥ 25 %, umbilical artery PI of the smaller fetus > 95th percentile).

  • For DC twins, at least 2 of the following 3 parameters must be met (fetal weight of one fetus < 10th percentile, EFW differential ≥ 25 %, umbilical artery PI of the smaller fetus > 95th percentile) [32].

  • Monitoring should be intensified in MC twins with a weight discrepancy ≥ 20 % as this is associated with increased intrauterine mortality and perinatal morbidity [33] [34].

  • The estimated weight discordance should be calculated using the following formula:

  • (weight of the larger twin – weight of the smaller twin) × 100/weight of the larger twin [1].

  • A search for the underlying causes of sFGR should include the following examinations: ultrasound scan, Doppler sonography, genetic familly history and testing, infection screening [35].

  • In MC twin pregnancies, sFGR is mainly due to unequal placental sharing [36].


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Screening for FGR in Twin Pregnancy

  • A combination of head, abdomen and femur measurements is best used to estimate fetal weight [37].

  • If the difference in the estimated fetal weights is ≥ 25 %, the patient should be referred to a Level 1 Perinatal Medicine Center [1].


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Classification of sFGR in MC Twin Pregnancy

In MC DA twins sFGR is classified based on the end-diastolic flow profile of the umbilical arteries: [38].

  • Type I: EDF-positive

  • Type II AREDF

  • Type III: cyclical/intermittent AREDF

EDF: end-diastolic flow
AREDF: absent or reversed end diastolic flow ([Fig. 4])

Zoom Image
Fig. 4 Classification of selective fetal growth restriction in monochorionic twin pregnancies. In Type I, the umbilical artery waveform shows a positive end-diastolic flow, while in Type II there is persistent absent or reverse end-diastolic flow (AREDF). In Type III there is a cyclical/intermittent AREDF pattern alternating with positive flow. Source: Arbeitsgemeinschaft der Wissenschaftlichen Medizinischen Fachgesellschaften e.V (AWMF). Leitlinie zur Überwachung und Betreuung von Zwillingsschwangerschaften. Online: https://www.awmf.org/leitlinien/detail/ll/015-087.html; Stand: 05.10.2020. [rerif]

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Management of Twin Pregnancy complicated by sFGR

  • DC twin pregnancies with sFGR should be monitored like singletons with FGR [1].

  • There is limited evidence available to guide the management of MC twins affected by sFGR.

  • Possible options include: conservative management followed by early delivery, laser ablation, or cord occlusion of the growth-restricting twin (in order to protect the other twin) [39].


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Follow-up of Twin Pregnancy complicated by sFGR

  • In DC twin pregnancy complicated by sFGR, fetal Doppler examinations should be performed approximately every two weeks.

  • Fetal Doppler examinations should be performed at least every week for MC twin pregnancies.

  • Management of MC DA twin pregnancies affected by sFGR is complex and should be performed at a Perinatal Center [39].

  • The timing of delivery should be based on the evaluation of interval growth, fetal Doppler findings and/or CTG and, if available, computerized CTG analysis [1].


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Management of the surviving Twin after Demise of the Cotwin

  • When a single intrauterine demise occurs in an MC pregnancy, the woman should be referred to a Perinatal center,

  • A Doppler examination of the middle cerebral artery should be performed with measurement of maximum velocity (Vmax) in order to estimate the probability of fetal anemia [1] [40].

When one MC twin dies in utero, the surviving twin may then lose part of its circulating volume to the dead twin, leading to potentially severe hypotension in the survivor, which can lead to hypoperfusion of the brain and other organs, potentially causing brain damage or death [41].

The following complications can occur after a single intrauterine demise of an MC or DC twin [41] [42]:

  • Death of a cotwin 15 % and 3 %

  • Preterm delivery 68 % and 3 %

  • Abnormal cranial image of the cotwin 34 % and 16 %

  • Neurodevelopmental impairment of the surviving cotwin 26 % and 2 %

  • Brain damage is usually the result of a hypoxic-ischemic lesion that results in the development of cystic periventricular leukomalacia, infarction of the middle cerebral artery, or damage to the basal ganglia, thalamus and/or cortex.

  • Pre- and postnatal imaging including high-resolution ultrasound and, if necessary, an MRI should be performed.

  • Additionally, there should be long-term pediatric follow-up [43].

  • If there is strong suspicion that the surviving twin may have suffered serious neurological damage, late termination of pregnancy should be considered as an option [1].


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Complications unique to Monochorionic Twin Pregnancy

Complications that occur exclusively in MC twin pregnancies are TTTS, TAPS and TRAP sequence, monoamniotic pregnancies and conjoined twins.

Twin-to-Twin-Transfusion Syndrome (TTTS)

TTTS Staging

  • The Quintero staging system is the most widely used classification system of TTTS [44].

  • This system is not always predictive of the outcome and is not always chronological, e. g. Stage I can lead directly to Stage III or intrauterine fetal death [1] ([Fig. 5], [Table 1]).

Zoom Image
Fig. 5 Sonographic image of TTTS with a polyhydramnion of the recipient and b oligohydramnios of the donor. Source: Arbeitsgemeinschaft der Wissenschaftlichen Medizinischen Fachgesellschaften e.V (AWMF). Leitlinie zur Überwachung und Betreuung von Zwillingsschwangerschaften. Online: https://www.awmf.org/leitlinien/detail/ll/015-087.html; Stand: 05.10.2020. [rerif]
Table 1

Staging system modified according to Quintero [44].

stage

classification

I

oligohydramnios-polyhydramnios sequence

  • donor: DVP < 2 cm

  • recipient: DVP > 8 cm (≤ 20 weeks gestation), > 10 cm (> 20 weeks gestation)

II

  • donor: urinary bladder not visible in ultrasound

III

  • absent or reversed umbilical-arterial diastolic flow

  • absent or reversed a-wave in ductus venosus

  • pulsatile umbilical-venous flow in one of the twins

IV

  • hydrops in one or both twins

DVP, deepest vertical pocket (amniotic fluid depot).


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Screening for TTTS

  • In MC twin pregnancy, screening for TTTS should start at 16 weeks of gestation, with scans repeated every 2 weeks thereafter [1].

  • If TTTS is diagnosed, the patient should be referred to a specialized center as soon as the following criteria are met:

  • Donor: DVP < 2 cm

  • Recipient: DVP > 8 cm (≤ 20 weeks gestation) or > 10 cm (> 20 weeks gestation) [1] [3]

  • MC twin pregnancies with amniotic fluid discordance should be checked on a weekly basis to rule out progression to TTTS [1].


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TTTS Therapy

  • Laser ablation is the treatment of choice for TTTS.

  • Patients with TTTS should be referred promptly to a center providing this therapy [45] [46] [47].

  • Conservative management with close monitoring may be considered for Quintero Stage I without maternal complications due to a massive polyhydramnion or short cervix [1] [48].

  • After laser therapy, further ultrasound examinations should initially be performed weekly and every two weeks if symptoms subside [1].


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Neurological follow-up for TTTS

MC twin pregnancies with TTTS have an increased risk of brain abnormalities and delayed neurological development. Both donor and recipient are at increased risk for ischemic or hemorrhagic lesions. The risk for neurological developmental disorders after laser therapy is between 4 % and 13 % and is thus about half as low as after amniotic reduction [49].


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Twin Anemia-Polycythemia Sequence (TAPS)

  • TAPS is based on the findings of discordant systolic Vmax values of the middle cerebral artery in both fetuses [1] [50] [51].

  • There is limited evidence regarding the outcome and optimal management of TAPS; therefore treatment options should be individualized and discussed with the parents [1].

  • MC twins with TAPS have an increased risk of delayed neurological development.

  • Cerebral imaging in the third trimester and a developmental neurological examination at the age of 2 years is recommended [52] [53] ([Table 2]).

Table 2

Antenatal and postnatal stage classification of the Twin Anemia Polycythemia Sequence (TAPS), modified according to Slaghekke and Lopriore [54] [55].

stage

antenatal staging

postnatal staging

interfetal Hb differential (g/dL)

1

MCA-PSV donor 1.5 MoM and recipient < 1.0 MoM, without other signs of fetal compromise

> 8.0

2

MCA-PSV donor 1.7 MoM and recipient < 0.8 MoM, without other signs of fetal compromise

> 11.0

3

stage 1 or 2 with donor cardiac compromise umbilical artery AREDF, umbilical vein pulsatile, DV PVIV raised/a-wave negative

> 14.0

4

donor hydrops

> 17.0

Hb: hemoglobin; MCA: middle cerebral artery; MoM: multiple of median value; PSV: peak systolic velocity (Vmax of middle cerebral artery).


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Twin Reversed Arterial Perfusion (TRAP) Sequence

  • The chances of survival of the pumping twin can be increased by using minimally invasive techniques (e. g. laser coagulation of the anastomoses as well as intrafetal methods, umbilical cord coagulation), if necessary even before 16 weeks [1] [56] [57] [58] ([Fig. 6], [7]).

Zoom Image
Fig. 6a Sagittal visualization of a TRAP fetus, b visualization of retrograde blood flow in the TRAP fetus. Source: Arbeitsgemeinschaft der Wissenschaftlichen Medizinischen Fachgesellschaften e.V (AWMF). Leitlinie zur Überwachung und Betreuung von Zwillingsschwangerschaften. Online: https://www.awmf.org/leitlinien/detail/ll/015-087.html; Stand: 05.10.2020. [rerif]
Zoom Image
Fig. 7 Diagnostic algorithm for monochorionic-diamniotic twins with discordant findings. Source: Arbeitsgemeinschaft der Wissenschaftlichen Medizinischen Fachgesellschaften e.V (AWMF). Leitlinie zur Überwachung und Betreuung von Zwillingsschwangerschaften. Online: https://www.awmf.org/leitlinien/detail/ll/015-087.html; Stand: 05.10.2020. [rerif]

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MC MA Twins

  • Umbilical cord entanglement is almost always present in MC MA twins and does not appear to contribute essentially to morbidity and mortality [59].


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Conjoined Twins

Conjoined twins are very rare and are always MC MA pregnancies. Ultrasound diagnosis in the first trimester is now common by visualization of near and fixed fetal bodies with partial fusion of the bodies ([Fig. 8]).

Zoom Image
Fig. 8 Three-dimensional ultrasound image of a cephalopagus at 10 weeks of gestation. Source: Arbeitsgemeinschaft der Wissenschaftlichen Medizinischen Fachgesellschaften e.V (AWMF). Leitlinie zur Überwachung und Betreuung von Zwillingsschwangerschaften. Online: https://www.awmf.org/leitlinien/detail/ll/015-087.html; Stand: 05.10.2020. [rerif]

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Time of birth for twin pregnancies

Time of Birth of uncomplicated DC DA and MC DA Twins

  • Uncomplicated DC twins should be delivered at between 37+ 0–38+ 0 weeks of gestation.

  • Uncomplicated MC DA twins should be delivered at between 36+ 0–37+ 0 weeks of gestation [60] [61] [62] [63] [64].


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Time of Birth of uncomplicated MC MA Twins

  • Uncomplicated MC MA twins should be delivered at between 32+ 0–32+ 6 weeks of gestation [3] [65] [66].

The decision to deliver uncomplicated MC MA twins between 32+ 0–32+ 6 weeks of gestation is based on the observation that intrauterine mortality doubles subsequently [65] [66].

The recommendation on the time of birth for MC MA twins was adopted by expert consensus due to the lack of randomized trials ([Table 3]).

Table 3

Recommended time of birth of uncomplicated dichorial (DC), monochorionic diamniotic (MC DA) and monochorionic monoamniotic (MC MA) twins according to international guidelines [3] [67] [68] [69] [70].

professional Society

DC twins

MC DA twins

MC MA twins

National Guideline Alliance (UK). Twin and Triplet Pregnancy. London: National Institute for Health and Care Excellence (UK); 2019 [3]

37+ 0 – 37+ 6

36+ 0 – 36+ 6

(after LMI)

32+ 0 – 33+ 6

Royal College of Obstetricians and Gynaecologists (RCOG) [67]

from 36+ 0

(after LMI)

32+ 0 – 34+ 6

American College of Obstetricians and Gynecologists (ACOG) [68]

38

34+ 0 – 37+ 6

32–34

Royal Australian and New Zealand College of Obstetricians and Gynecologists (RANZ-COG) [69]

up to 37

French College of Gynaecologists and Obstetricians (CNGOF) [70]

38 – < 40

36 – < 38+ 6

32 – < 36

LMI = Lung Maturation Induction; GW = gestation weeks (completed weeks and additional days).


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Delivery Mode for Twin Pregnancies

Delivery Mode for uncomplicated DC and MC DA Twins > 32 Weeks of Gestation

  • Uncomplicated twins > 32 weeks of gestation, first twin in cephalic position, without contraindications or growth discordance, can be delivered vaginally or by C-section.

  • Chorionicity plays no role in delivery mode [71] [72] [73] [74] [75] [76] [77] [78].


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Delivery Mode for uncomplicated DC and MC DA Twins < 32 Weeks of Gestation

  • There is insufficient evidence available to offer a firm recommendation for the delivery of uncomplicated twins < 32 weeks of gestation [79] [80].


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Delivery Mode for uncomplicated MC MA Twins

The recommendation on the delivery mode for MC MA twins was adopted by expert consensus due to the lack of randomized studies.

  • MC MA twins should be delivered by C-section [3] ([Table 4]).

Table 4

Overview of recommendations of national professional societies on the delivery mode in uncomplicated dichorial, monochorial and monoamnial twins [3] [67] [68] [69] [70].

professional Society

DC DA twins

MC DA twins

MC MA twins

National Guideline Alliance (UK). Twin and Triplet Pregnancy. London: National Institute for Health and Care Excellence (UK); 2019 [3]

vaginal delivery under the the following conditions:

  • uncomplicated pregnancy

  • > 32 weeks of gestation

  • no contraindications

  • first child in cephalic position

  • no significance discordance in EFW

vaginal delivery under the the following conditions:

  • uncomplicated pregnancy

  • > 32 weeks of gestation

  • no contraindications

  • first child in cephalic position

  • no significance discordance in EFW

primary C-section

Royal College of Obstetricians and Gynaecologists (RCOG) [67]

planned vaginal birth

primary C-section

American College of Obstetricians and Gynecologists (ACOG) [68]

planned vaginal birth > 32+ 0 GW

regardless whether twin II in cephalic or breech presentation

planned vaginal birth > 32+ 0 GW regardless whether twin II in cephalic or breech presentation

primary C-section

Royal Australian and New Zealand College of Obstetricians and Gynecologists (RANZ-COG) [69]

planned vaginal birth only when sufficient infrastructure available for continuous fetal monitoring or emergency C-section

planned vaginal birth only when sufficient infrastructure available for continuous fetal monitoring or emergency C-section

French College of Gynaecologists and Obstetricians (CNGOF) [70]

vaginal birth regardless of gestational age and child presentation

vaginal birth regardless of gestational age and child presentation


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Funding

Deutsche Stiftung Frauengesundheit, Deutsche Gesellschaft für Gynäkologie und Geburtshilfe (DGGG), Deutsche Gesellschaft für Ultraschall in der Medizin (DEGUM).


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Conflict of Interest

The authors declare that they have no conflict of interest.

* Constantin von Kaisenberg and Philipp Klaritsch share first authorship.


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  • 4 Dias T, Mahsud-Dornan S, Thilaganathan B. et al. First-trimester ultrasound dating of twin pregnancy: are singleton charts reliable?. BJOG 2010; 117: 979-984
  • 5 Salomon LJ, Cavicchioni O, Bernard JP. et al. Growth discrepancy in twins in the first trimester of pregnancy. Ultrasound Obstet Gynecol 2005; 26: 512-516
  • 6 Maruotti GM, Saccone G, Morlando M. et al. First-trimester ultrasound determination of chorionicity in twin gestations using the lambda sign: a systematic review and meta-analysis. Eur J Obstet Gynecol Reprod Biol 2016; 202: 66-70
  • 7 Dias T, Ladd S, Mahsud-Dornan S. et al. Systematic labeling of twin pregnancies on ultrasound. Ultrasound Obstet Gynecol 2011; 38: 130-133
  • 8 D'Antonio F, Khalil A, Thilaganathan B. et al. Second-trimester discordance and adverse perinatal outcome in twins: the STORK multiple pregnancy cohort. BJOG 2014; 121: 422-429
  • 9 Sueters M, Middeldorp JM, Lopriore E. et al. Timely diagnosis of twin-to-twin transfusion syndrome in monochorionic twin pregnancies by biweekly sonography combined with patient instruction to report onset of symptoms. Ultrasound Obstet Gynecol 2006; 28: 659-664
  • 10 de Villiers SF, Slaghekke F, Middeldorp JM. et al. Placental characteristics in monochorionic twins with spontaneous versus post-laser twin anemia-polycythemia sequence. Placenta 2013; 34: 456-459
  • 11 Prats P, Rodriguez I, Comas C. et al. Systematic review of screening for trisomy 21 in twin pregnancies in first trimester combining nuchal translucency and biochemical markers: a meta-analysis. Prenat Diagn 2014; 34: 1077-1083
  • 12 Kagan KO, Sonek J, Wagner P. et al. Principles of first trimester screening in the age of non-invasive prenatal diagnosis: screening for other major defects and pregnancy complications. Arch Gynecol Obstet 2017; 296: 635-643
  • 13 Dagklis T, Plasencia W, Maiz N. et al. Choroid plexus cyst, intracardiac echogenic focus, hyperechogenic bowel and hydronephrosis in screening for trisomy 21 at 11 + 0 to 13 + 6 weeks. Ultrasound Obstet Gynecol 2008; 31: 132-135
  • 14 Chaveeva P, Wright A, Syngelaki A. et al. First-trimester screening for trisomies in pregnancies with vanishing twin. Ultrasound Obstet Gynecol 2020; 55: 326-331
  • 15 Gil MM, Accurti V, Santacruz B. et al. Analysis of cell-free DNA in maternal blood in screening for aneuploidies: updated meta-analysis. Ultrasound Obstet Gynecol 2017; 50: 302-314
  • 16 Salomon LJ, Alfirevic Z, Bilardo CM. et al. ISUOG practice guidelines: performance of first-trimester fetal ultrasound scan. Ultrasound Obstet Gynecol 2013; 41: 102-113
  • 17 von Kaisenberg C, Chaoui R, Häusler M. et al. Qualitätsanforderungen an die Ultraschalluntersuchung in der Frühschwangerschaft (DEGUM-Stufe I) zwischen 4+0 und 13+6 Schwangerschaftswochen. Ultraschall in Med 2016; 37: 297-302
  • 18 Agarwal K, Alfirevic Z. Pregnancy loss after chorionic villus sampling and genetic amniocentesis in twin pregnancies: a systematic review. Ultrasound Obstet Gynecol 2012; 40: 128-134
  • 19 Gallot D, Velemir L, Delabaere A. et al. [Which invasive diagnostic procedure should we use for twin pregnancies: chorionic villous sampling or amniocentesis?]. J Gynecol Obstet Biol Reprod (Paris) 2009; 38: S39-S44
  • 20 Hansen M, Kurinczuk JJ, Milne E. et al. Assisted reproductive technology and birth defects: a systematic review and meta-analysis. Hum Reprod Update 2013; 19: 330-353
  • 21 Ghi T, Sotiriadis A, Calda P. et al. ISUOG Practice Guidelines: invasive procedures for prenatal diagnosis. Ultrasound Obstet Gynecol 2016; 48: 256-268
  • 22 Evans MI, Goldberg JD, Horenstein J. et al. Selective termination for structural, chromosomal, and mendelian anomalies: international experience. Am J Obstet Gynecol 1999; 181: 893-897
  • 23 Kagan KO, Gazzoni A, Sepulveda-Gonzalez G. et al. Discordance in nuchal translucency thickness in the prediction of severe twin-to-twin transfusion syndrome. Ultrasound Obstet Gynecol 2007; 29: 527-532
  • 24 Mackie FL, Hall MJ, Morris RK. et al. Early prognostic factors of outcomes in monochorionic twin pregnancy: systematic review and meta-analysis. Am J Obstet Gynecol 2018; 219: 436-446
  • 25 Merz E, Eichhorn KH, von Kaisenberg C. et al. Aktualisierte Qualitätsanforderungen an die weiterführende differenzierte Ultraschalluntersuchung in der pränatalen Diagnostik (= DEGUM-Stufe II) im Zeitraum von 18 + 0 bis 21 + 6 Schwangerschaftswochen. Ultraschall in Med 2012; 33: 593-596
  • 26 Carvalho JS. Gynecology ISoUiOa, Gynecology. et al. ISUOG Practice Guidelines (updated): sonographic screening examination of the fetal heart. Ultrasound Obstet Gynecol 2013; 41: 348-359
  • 27 Chaoui R, Heling K, Mielke G. et al. Qualitätsanforderungen der DEGUM zur Durchführung der fetalen Echokardiografie. Ultraschall in Med 2008; 29: 197-200
  • 28 Machin G. Non-identical monozygotic twins, intermediate twin types, zygosity testing, and the non-random nature of monozygotic twinning: a review. Am J Med Genet C Semin Med Genet 2009; 151C: 110-127
  • 29 Lewi L, Blickstein I, Van Schoubroeck D. et al. Diagnosis and management of heterokaryotypic monochorionic twins. Am J Med Genet A 2006; 140: 272-275
  • 30 Lewi L, Gratacos E, Ortibus E. et al. Pregnancy and infant outcome of 80 consecutive cord coagulations in complicated monochorionic multiple pregnancies. Am J Obstet Gynecol 2006; 194: 782-789
  • 31 Conde-Agudelo A, Romero R, Hassan SS. et al. Transvaginal sonographic cervical length for the prediction of spontaneous preterm birth in twin pregnancies: a systematic review and metaanalysis. Am J Obstet Gynecol 2010; 203: 128e121–112
  • 32 Khalil A, Beune I, Hecher K. et al. Consensus definition and essential reporting parameters of selective fetal growth restriction in twin pregnancy: a Delphi procedure. Ultrasound Obstet Gynecol 2019; 53: 47-54
  • 33 Leombroni M, Liberati M, Fanfani F. et al. Diagnostic accuracy of ultrasound in predicting birth-weight discordance in twin pregnancy: systematic review and meta-analysis. Ultrasound Obstet Gynecol 2017; 50: 442-450
  • 34 D’Antonio F, Odibo AO, Prefumo F. et al. Weight discordance and perinatal mortality in twin pregnancy: systematic review and meta-analysis. Ultrasound Obstet Gynecol 2018; 52: 11-23
  • 35 Sueters M, Oepkes D. Diagnosis of twin-to-twin transfusion syndrome, selective fetal growth restriction, twin anaemia-polycythaemia sequence, and twin reversed arterial perfusion sequence. Best Pract Res Clin Obstet Gynaecol 2014; 28: 215-226
  • 36 Lewi L, Gucciardo L, Huber A. et al. Clinical outcome and placental characteristics of monochorionic diamniotic twin pairs with early- and late-onset discordant growth. Am J Obstet Gynecol 2008; 199: 511e511-e517
  • 37 Khalil A, D'Antonio F, Dias T. et al. Ultrasound estimation of birth weight in twin pregnancy: comparison of biometry algorithms in the STORK multiple pregnancy cohort. Ultrasound Obstet Gynecol 2014; 44: 210-220
  • 38 Gratacos E, Lewi L, Munoz B. et al. A classification system for selective intrauterine growth restriction in monochorionic pregnancies according to umbilical artery Doppler flow in the smaller twin. Ultrasound Obstet Gynecol 2007; 30: 28-34
  • 39 Chalouhi GE, Marangoni MA, Quibel T. et al. Active management of selective intrauterine growth restriction with abnormal Doppler in monochorionic diamniotic twin pregnancies diagnosed in the second trimester of pregnancy. Prenat Diagn 2013; 33: 109-115
  • 40 Senat MV, Loizeau S, Couderc S. et al. The value of middle cerebral artery peak systolic velocity in the diagnosis of fetal anemia after intrauterine death of one monochorionic twin. Am J Obstet Gynecol 2003; 189: 1320-1324
  • 41 Hillman SC, Morris RK, Kilby MD. Co-twin prognosis after single fetal death: a systematic review and meta-analysis. Obstet Gynecol 2011; 118: 928-940
  • 42 Ong SS, Zamora J, Khan KS. et al. Prognosis for the co-twin following single-twin death: a systematic review. BJOG 2006; 113: 992-998
  • 43 van Klink JM, van Steenis A, Steggerda SJ. et al. Single fetal demise in monochorionic pregnancies: incidence and patterns of cerebral injury. Ultrasound Obstet Gynecol 2015; 45: 294-300
  • 44 Quintero RA, Morales WJ, Allen MH. et al. Staging of twin-twin transfusion syndrome. J Perinatol 1999; 19: 550-555
  • 45 Roberts D, Neilson JP, Kilby MD. et al. Interventions for the treatment of twin-twin transfusion syndrome. Cochrane Database Syst Rev 2014; DOI: 10.1002/14651858.CD002073.pub3:CD002073.
  • 46 Senat MV, Deprest J, Boulvain M. et al. Endoscopic laser surgery versus serial amnioreduction for severe twin-to-twin transfusion syndrome. N Engl J Med 2004; 351: 136-144
  • 47 Diehl W, Diemert A, Grasso D. et al. Fetoscopic laser coagulation in 1020 pregnancies with twin-twin transfusion syndrome demonstrates improvement in double-twin survival rate. Ultrasound Obstet Gynecol 2017; 50: 728-735
  • 48 Khalil A, Cooper E, Townsend R. et al. Evolution of Stage 1 Twin-to-Twin Transfusion Syndrome (TTTS): Systematic Review and Meta-Analysis. Twin Res Hum Genet 2016; 19: 207-216
  • 49 Hecher K, Gardiner HM, Diemert A. et al. Long-term outcomes for monochorionic twins after laser therapy in twin-to-twin transfusion syndrome. Lancet Child Adolesc Health 2018; 2: 525-535
  • 50 Khalil A, Gordijn S, Ganzevoort W. et al. Consensus diagnostic criteria and monitoring of twin anemia polycythemia sequence: a Delphi procedure. Ultrasound Obstet Gynecol 2019; DOI: 10.1002/uog.21882.
  • 51 Tavares de Sousa M, Fonseca A, Hecher K. Role of fetal intertwin difference in middle cerebral artery peak systolic velocity in predicting neonatal twin anemia-polycythemia sequence. Ultrasound Obstet Gynecol 2019; 53: 794-797
  • 52 Slaghekke F, van Klink JM, Koopman HM. et al. Neurodevelopmental outcome in twin anemia-polycythemia sequence after laser surgery for twin-twin transfusion syndrome. Ultrasound Obstet Gynecol 2014; 44: 316-321
  • 53 Tollenaar LSA, Lopriore E, Slaghekke F. et al. High risk of long-term neurodevelopmental impairment in donor twins with spontaneous twin anemia-polycythemia sequence. Ultrasound Obstet Gynecol 2020; 55: 39-46
  • 54 Slaghekke F, Kist WJ, Oepkes D. et al. Twin anemia-polycythemia sequence: diagnostic criteria, classification, perinatal management and outcome. Fetal Diagn Ther 2010; 27: 181-190
  • 55 Lopriore E, Slaghekke F, Oepkes D. et al. Hematological characteristics in neonates with twin anemia-polycythemia sequence (TAPS). Prenat Diagn 2010; 30: 251-255
  • 56 Hecher K, Lewi L, Gratacos E. et al. Twin reversed arterial perfusion: fetoscopic laser coagulation of placental anastomoses or the umbilical cord. Ultrasound Obstet Gynecol 2006; 28: 688-691
  • 57 Pagani G, D'Antonio F, Khalil A. et al. Intrafetal laser treatment for twin reversed arterial perfusion sequence: cohort study and meta-analysis. Ultrasound Obstet Gynecol 2013; 42: 6-14
  • 58 Tavares de Sousa M, Glosemeyer P, Diemert A. et al. First-trimester intervention in twin reversed arterial perfusion sequence. Ultrasound Obstet Gynecol 2020; 55: 47-49
  • 59 Rossi AC, Prefumo F. Impact of cord entanglement on perinatal outcome of monoamniotic twins: a systematic review of the literature. Ultrasound Obstet Gynecol 2013; 41: 131-135
  • 60 Dodd JM, Deussen AR, Grivell RM. et al. Elective birth at 37 weeks’ gestation for women with an uncomplicated twin pregnancy. Cochrane Database Syst Rev 2014; DOI: 10.1002/14651858.CD003582.pub2:CD003582.
  • 61 Saccone G, Berghella V. Planned delivery at 37 weeks in twins: a systematic review and meta-analysis of randomized controlled trials. J Matern Fetal Neonatal Med 2016; 29: 685-689
  • 62 Cheong-See F, Schuit E, Arroyo-Manzano D. et al. Prospective risk of stillbirth and neonatal complications in twin pregnancies: systematic review and meta-analysis. BMJ 2016; 354: i4353
  • 63 Danon D, Sekar R, Hack KE. et al. Increased stillbirth in uncomplicated monochorionic twin pregnancies: a systematic review and meta-analysis. Obstet Gynecol 2013; 121: 1318-1326
  • 64 Page JM, Pilliod RA, Snowden JM. et al. The risk of stillbirth and infant death by each additional week of expectant management in twin pregnancies. Am J Obstet Gynecol 2015; 212: 630e631-637
  • 65 D'Antonio F, Odibo A, Berghella V. et al. Perinatal mortality, timing of delivery and prenatal management of monoamniotic twin pregnancy: systematic review and meta-analysis. Ultrasound Obstet Gynecol 2019; 53: 166-174
  • 66 Van Mieghem T, De Heus R, Lewi L. et al. Prenatal management of monoamniotic twin pregnancies. Obstet Gynecol 2014; 124: 498-506
  • 67 Kilby M, Bricker LobotRCoOaG. Management of Monochorionic Twin Pregnancy: Green-top Guideline No. 51. BJOG 2017; 124: e1-e45
  • 68 Committee on Practice B-O, Society for Maternal-Fetal M. Practice Bulletin No. 169: Multifetal Gestations: Twin, Triplet, and Higher-Order Multifetal Pregnancies. Obstet Gynecol 2016; 128: e131-e146
  • 69 RANZCOG, Board, Council. Management of monochorionic twin pregnancy. College Statement 42 2011. https://ranzcog.edu.au/RANZCOG_SITE/media/RANZCOG-MEDIA/Women%27s%20Health/Statement%20and%20guidelines/Clinical-Obstetrics/Management-of-Monochorionic-Twins-(C-Obs-42)-review-July-2017.pdf?ext=.pdf
  • 70 Vayssiere C, Benoist G, Blondel B. et al. Twin pregnancies: guidelines for clinical practice from the French College of Gynaecologists and Obstetricians (CNGOF). Eur J Obstet Gynecol Reprod Biol 2011; 156: 12-17
  • 71 Barrett JF, Hannah ME, Hutton EK. et al. A randomized trial of planned cesarean or vaginal delivery for twin pregnancy. N Engl J Med 2013; 369: 1295-1305
  • 72 Hofmeyr GJ, Barrett JF, Crowther CA. Planned caesarean section for women with a twin pregnancy. Cochrane Database Syst Rev 2015; DOI: 10.1002/14651858.CD006553.pub3:CD006553.
  • 73 Asztalos EV, Hannah ME, Hutton EK. et al. Twin Birth Study: 2-year neurodevelopmental follow-up of the randomized trial of planned cesarean or planned vaginal delivery for twin pregnancy. Am J Obstet Gynecol 2016; 214: 371e371-371, e319
  • 74 Hutton EK, Hannah ME, Ross S. et al. Maternal outcomes at 3 months after planned caesarean section versus planned vaginal birth for twin pregnancies in the Twin Birth Study: a randomised controlled trial. BJOG 2015; 122: 1653-1662
  • 75 Schmitz T, Korb D, Battie C. et al. Neonatal morbidity associated with vaginal delivery of noncephalic second twins. Am J Obstet Gynecol 2018; 218: 449e441-449, e413
  • 76 Schmitz T, Prunet C, Azria E. et al. Association Between Planned Cesarean Delivery and Neonatal Mortality and Morbidity in Twin Pregnancies. Obstet Gynecol 2017; 129: 986-995
  • 77 Goossens S, Ensing S, van der Hoeven M. et al. Comparison of planned caesarean delivery and planned vaginal delivery in women with a twin pregnancy: A nation wide cohort study. Eur J Obstet Gynecol Reprod Biol 2018; 221: 97-104
  • 78 Korb D, Deneux-Tharaux C, Seco A. et al. Risk of Severe Acute Maternal Morbidity According to Planned Mode of Delivery in Twin Pregnancies. Obstet Gynecol 2018; 132: 647-655
  • 79 Dagenais C, Lewis-Mikhael AM, Grabovac M. et al. What is the safest mode of delivery for extremely preterm cephalic/non-cephalic twin pairs? A systematic review and meta-analyses. BMC Pregnancy Childbirth 2017; 17: 397
  • 80 Sentilhes L, Oppenheimer A, Bouhours AC. et al. Neonatal outcome of very preterm twins: policy of planned vaginal or cesarean delivery. Am J Obstet Gynecol 2015; 213: 73e71-73, e77

Correspondence

Prof. Constantin von Kaisenberg
Obstetrics and Gynecology, Hannover Medical School
Carl-Neuberg-Str. 1
30625 Hannover
Germany   
Telefon: ++ 49/1 76/15 32 34 54   
Fax: ++ 49/51 15 32 61 45   

Publikationsverlauf

Eingereicht: 29. Mai 2020

Angenommen: 09. August 2020

Artikel online veröffentlicht:
05. Oktober 2020

© 2020. Thieme. All rights reserved.

Georg Thieme Verlag KG
Rüdigerstraße 14, 70469 Stuttgart, Germany

  • References

  • 1 Khalil A, Rodgers M, Baschat A. et al. ISUOG Practice Guidelines: role of ultrasound in twin pregnancy. Ultrasound Obstet Gynecol 2016; 47: 247-263
  • 2 NICE. National Institute for Health and Care Excellence Clinical Guideline 129: Multiple Pregnancy – The Management of Twin and Triplet Pregnancies in the Antenatal Period. London: 2011 In, Multiple Pregnancy: The Management of Twin and Triplet Pregnancies in the Antenatal Period
  • 3 NICE. National Institute for Health and Care Excellence Guideline 137: Twin and Triplet Pregnancy. London: 2019
  • 4 Dias T, Mahsud-Dornan S, Thilaganathan B. et al. First-trimester ultrasound dating of twin pregnancy: are singleton charts reliable?. BJOG 2010; 117: 979-984
  • 5 Salomon LJ, Cavicchioni O, Bernard JP. et al. Growth discrepancy in twins in the first trimester of pregnancy. Ultrasound Obstet Gynecol 2005; 26: 512-516
  • 6 Maruotti GM, Saccone G, Morlando M. et al. First-trimester ultrasound determination of chorionicity in twin gestations using the lambda sign: a systematic review and meta-analysis. Eur J Obstet Gynecol Reprod Biol 2016; 202: 66-70
  • 7 Dias T, Ladd S, Mahsud-Dornan S. et al. Systematic labeling of twin pregnancies on ultrasound. Ultrasound Obstet Gynecol 2011; 38: 130-133
  • 8 D'Antonio F, Khalil A, Thilaganathan B. et al. Second-trimester discordance and adverse perinatal outcome in twins: the STORK multiple pregnancy cohort. BJOG 2014; 121: 422-429
  • 9 Sueters M, Middeldorp JM, Lopriore E. et al. Timely diagnosis of twin-to-twin transfusion syndrome in monochorionic twin pregnancies by biweekly sonography combined with patient instruction to report onset of symptoms. Ultrasound Obstet Gynecol 2006; 28: 659-664
  • 10 de Villiers SF, Slaghekke F, Middeldorp JM. et al. Placental characteristics in monochorionic twins with spontaneous versus post-laser twin anemia-polycythemia sequence. Placenta 2013; 34: 456-459
  • 11 Prats P, Rodriguez I, Comas C. et al. Systematic review of screening for trisomy 21 in twin pregnancies in first trimester combining nuchal translucency and biochemical markers: a meta-analysis. Prenat Diagn 2014; 34: 1077-1083
  • 12 Kagan KO, Sonek J, Wagner P. et al. Principles of first trimester screening in the age of non-invasive prenatal diagnosis: screening for other major defects and pregnancy complications. Arch Gynecol Obstet 2017; 296: 635-643
  • 13 Dagklis T, Plasencia W, Maiz N. et al. Choroid plexus cyst, intracardiac echogenic focus, hyperechogenic bowel and hydronephrosis in screening for trisomy 21 at 11 + 0 to 13 + 6 weeks. Ultrasound Obstet Gynecol 2008; 31: 132-135
  • 14 Chaveeva P, Wright A, Syngelaki A. et al. First-trimester screening for trisomies in pregnancies with vanishing twin. Ultrasound Obstet Gynecol 2020; 55: 326-331
  • 15 Gil MM, Accurti V, Santacruz B. et al. Analysis of cell-free DNA in maternal blood in screening for aneuploidies: updated meta-analysis. Ultrasound Obstet Gynecol 2017; 50: 302-314
  • 16 Salomon LJ, Alfirevic Z, Bilardo CM. et al. ISUOG practice guidelines: performance of first-trimester fetal ultrasound scan. Ultrasound Obstet Gynecol 2013; 41: 102-113
  • 17 von Kaisenberg C, Chaoui R, Häusler M. et al. Qualitätsanforderungen an die Ultraschalluntersuchung in der Frühschwangerschaft (DEGUM-Stufe I) zwischen 4+0 und 13+6 Schwangerschaftswochen. Ultraschall in Med 2016; 37: 297-302
  • 18 Agarwal K, Alfirevic Z. Pregnancy loss after chorionic villus sampling and genetic amniocentesis in twin pregnancies: a systematic review. Ultrasound Obstet Gynecol 2012; 40: 128-134
  • 19 Gallot D, Velemir L, Delabaere A. et al. [Which invasive diagnostic procedure should we use for twin pregnancies: chorionic villous sampling or amniocentesis?]. J Gynecol Obstet Biol Reprod (Paris) 2009; 38: S39-S44
  • 20 Hansen M, Kurinczuk JJ, Milne E. et al. Assisted reproductive technology and birth defects: a systematic review and meta-analysis. Hum Reprod Update 2013; 19: 330-353
  • 21 Ghi T, Sotiriadis A, Calda P. et al. ISUOG Practice Guidelines: invasive procedures for prenatal diagnosis. Ultrasound Obstet Gynecol 2016; 48: 256-268
  • 22 Evans MI, Goldberg JD, Horenstein J. et al. Selective termination for structural, chromosomal, and mendelian anomalies: international experience. Am J Obstet Gynecol 1999; 181: 893-897
  • 23 Kagan KO, Gazzoni A, Sepulveda-Gonzalez G. et al. Discordance in nuchal translucency thickness in the prediction of severe twin-to-twin transfusion syndrome. Ultrasound Obstet Gynecol 2007; 29: 527-532
  • 24 Mackie FL, Hall MJ, Morris RK. et al. Early prognostic factors of outcomes in monochorionic twin pregnancy: systematic review and meta-analysis. Am J Obstet Gynecol 2018; 219: 436-446
  • 25 Merz E, Eichhorn KH, von Kaisenberg C. et al. Aktualisierte Qualitätsanforderungen an die weiterführende differenzierte Ultraschalluntersuchung in der pränatalen Diagnostik (= DEGUM-Stufe II) im Zeitraum von 18 + 0 bis 21 + 6 Schwangerschaftswochen. Ultraschall in Med 2012; 33: 593-596
  • 26 Carvalho JS. Gynecology ISoUiOa, Gynecology. et al. ISUOG Practice Guidelines (updated): sonographic screening examination of the fetal heart. Ultrasound Obstet Gynecol 2013; 41: 348-359
  • 27 Chaoui R, Heling K, Mielke G. et al. Qualitätsanforderungen der DEGUM zur Durchführung der fetalen Echokardiografie. Ultraschall in Med 2008; 29: 197-200
  • 28 Machin G. Non-identical monozygotic twins, intermediate twin types, zygosity testing, and the non-random nature of monozygotic twinning: a review. Am J Med Genet C Semin Med Genet 2009; 151C: 110-127
  • 29 Lewi L, Blickstein I, Van Schoubroeck D. et al. Diagnosis and management of heterokaryotypic monochorionic twins. Am J Med Genet A 2006; 140: 272-275
  • 30 Lewi L, Gratacos E, Ortibus E. et al. Pregnancy and infant outcome of 80 consecutive cord coagulations in complicated monochorionic multiple pregnancies. Am J Obstet Gynecol 2006; 194: 782-789
  • 31 Conde-Agudelo A, Romero R, Hassan SS. et al. Transvaginal sonographic cervical length for the prediction of spontaneous preterm birth in twin pregnancies: a systematic review and metaanalysis. Am J Obstet Gynecol 2010; 203: 128e121–112
  • 32 Khalil A, Beune I, Hecher K. et al. Consensus definition and essential reporting parameters of selective fetal growth restriction in twin pregnancy: a Delphi procedure. Ultrasound Obstet Gynecol 2019; 53: 47-54
  • 33 Leombroni M, Liberati M, Fanfani F. et al. Diagnostic accuracy of ultrasound in predicting birth-weight discordance in twin pregnancy: systematic review and meta-analysis. Ultrasound Obstet Gynecol 2017; 50: 442-450
  • 34 D’Antonio F, Odibo AO, Prefumo F. et al. Weight discordance and perinatal mortality in twin pregnancy: systematic review and meta-analysis. Ultrasound Obstet Gynecol 2018; 52: 11-23
  • 35 Sueters M, Oepkes D. Diagnosis of twin-to-twin transfusion syndrome, selective fetal growth restriction, twin anaemia-polycythaemia sequence, and twin reversed arterial perfusion sequence. Best Pract Res Clin Obstet Gynaecol 2014; 28: 215-226
  • 36 Lewi L, Gucciardo L, Huber A. et al. Clinical outcome and placental characteristics of monochorionic diamniotic twin pairs with early- and late-onset discordant growth. Am J Obstet Gynecol 2008; 199: 511e511-e517
  • 37 Khalil A, D'Antonio F, Dias T. et al. Ultrasound estimation of birth weight in twin pregnancy: comparison of biometry algorithms in the STORK multiple pregnancy cohort. Ultrasound Obstet Gynecol 2014; 44: 210-220
  • 38 Gratacos E, Lewi L, Munoz B. et al. A classification system for selective intrauterine growth restriction in monochorionic pregnancies according to umbilical artery Doppler flow in the smaller twin. Ultrasound Obstet Gynecol 2007; 30: 28-34
  • 39 Chalouhi GE, Marangoni MA, Quibel T. et al. Active management of selective intrauterine growth restriction with abnormal Doppler in monochorionic diamniotic twin pregnancies diagnosed in the second trimester of pregnancy. Prenat Diagn 2013; 33: 109-115
  • 40 Senat MV, Loizeau S, Couderc S. et al. The value of middle cerebral artery peak systolic velocity in the diagnosis of fetal anemia after intrauterine death of one monochorionic twin. Am J Obstet Gynecol 2003; 189: 1320-1324
  • 41 Hillman SC, Morris RK, Kilby MD. Co-twin prognosis after single fetal death: a systematic review and meta-analysis. Obstet Gynecol 2011; 118: 928-940
  • 42 Ong SS, Zamora J, Khan KS. et al. Prognosis for the co-twin following single-twin death: a systematic review. BJOG 2006; 113: 992-998
  • 43 van Klink JM, van Steenis A, Steggerda SJ. et al. Single fetal demise in monochorionic pregnancies: incidence and patterns of cerebral injury. Ultrasound Obstet Gynecol 2015; 45: 294-300
  • 44 Quintero RA, Morales WJ, Allen MH. et al. Staging of twin-twin transfusion syndrome. J Perinatol 1999; 19: 550-555
  • 45 Roberts D, Neilson JP, Kilby MD. et al. Interventions for the treatment of twin-twin transfusion syndrome. Cochrane Database Syst Rev 2014; DOI: 10.1002/14651858.CD002073.pub3:CD002073.
  • 46 Senat MV, Deprest J, Boulvain M. et al. Endoscopic laser surgery versus serial amnioreduction for severe twin-to-twin transfusion syndrome. N Engl J Med 2004; 351: 136-144
  • 47 Diehl W, Diemert A, Grasso D. et al. Fetoscopic laser coagulation in 1020 pregnancies with twin-twin transfusion syndrome demonstrates improvement in double-twin survival rate. Ultrasound Obstet Gynecol 2017; 50: 728-735
  • 48 Khalil A, Cooper E, Townsend R. et al. Evolution of Stage 1 Twin-to-Twin Transfusion Syndrome (TTTS): Systematic Review and Meta-Analysis. Twin Res Hum Genet 2016; 19: 207-216
  • 49 Hecher K, Gardiner HM, Diemert A. et al. Long-term outcomes for monochorionic twins after laser therapy in twin-to-twin transfusion syndrome. Lancet Child Adolesc Health 2018; 2: 525-535
  • 50 Khalil A, Gordijn S, Ganzevoort W. et al. Consensus diagnostic criteria and monitoring of twin anemia polycythemia sequence: a Delphi procedure. Ultrasound Obstet Gynecol 2019; DOI: 10.1002/uog.21882.
  • 51 Tavares de Sousa M, Fonseca A, Hecher K. Role of fetal intertwin difference in middle cerebral artery peak systolic velocity in predicting neonatal twin anemia-polycythemia sequence. Ultrasound Obstet Gynecol 2019; 53: 794-797
  • 52 Slaghekke F, van Klink JM, Koopman HM. et al. Neurodevelopmental outcome in twin anemia-polycythemia sequence after laser surgery for twin-twin transfusion syndrome. Ultrasound Obstet Gynecol 2014; 44: 316-321
  • 53 Tollenaar LSA, Lopriore E, Slaghekke F. et al. High risk of long-term neurodevelopmental impairment in donor twins with spontaneous twin anemia-polycythemia sequence. Ultrasound Obstet Gynecol 2020; 55: 39-46
  • 54 Slaghekke F, Kist WJ, Oepkes D. et al. Twin anemia-polycythemia sequence: diagnostic criteria, classification, perinatal management and outcome. Fetal Diagn Ther 2010; 27: 181-190
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Fig. 1 First-trimester ultrasound images of: a dichorionic diamniotic twin pregnancy, in which the twins are separated by a thick layer of fused chorionic membranes, and b a monochorionic diamniotic twin pregnancy in which the twins are separated only by two thin amniotic membranes. Source: Arbeitsgemeinschaft der Wissenschaftlichen Medizinischen Fachgesellschaften e.V (AWMF). Leitlinie zur Überwachung und Betreuung von Zwillingsschwangerschaften. Online: https://www.awmf.org/leitlinien/detail/ll/015-087.html; Stand: 05.10.2020. [rerif]
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Fig. 2 Algorithm of ultrasound monitoring (completed weeks of pregnancy) for uncomplicated dichorial twin pregnancies. Source: Arbeitsgemeinschaft der Wissenschaftlichen Medizinischen Fachgesellschaften e.V (AWMF). Leitlinie zur Überwachung und Betreuung von Zwillingsschwangerschaften. Online: https://www.awmf.org/leitlinien/detail/ll/015-087.html; Stand: 05.10.2020. [rerif]
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Fig. 3 Algorithm of ultrasound monitoring (completed weeks of pregnancy) for uncomplicated monochorionic twin pregnancies. DVP: deepest vertical pocket; PI: pulsatility index; MCA-PSV: peak systolic velocity (Vmax of middle cerebral artery); A. umb: umbilical artery; MCA: middle cerebral artery; EFW: estimated fetal weight. Source: Arbeitsgemeinschaft der Wissenschaftlichen Medizinischen Fachgesellschaften e.V (AWMF). Leitlinie zur Überwachung und Betreuung von Zwillingsschwangerschaften. Online: https://www.awmf.org/leitlinien/detail/ll/015-087.html; Stand: 05.10.2020. [rerif]
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Fig. 4 Classification of selective fetal growth restriction in monochorionic twin pregnancies. In Type I, the umbilical artery waveform shows a positive end-diastolic flow, while in Type II there is persistent absent or reverse end-diastolic flow (AREDF). In Type III there is a cyclical/intermittent AREDF pattern alternating with positive flow. Source: Arbeitsgemeinschaft der Wissenschaftlichen Medizinischen Fachgesellschaften e.V (AWMF). Leitlinie zur Überwachung und Betreuung von Zwillingsschwangerschaften. Online: https://www.awmf.org/leitlinien/detail/ll/015-087.html; Stand: 05.10.2020. [rerif]
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Fig. 5 Sonographic image of TTTS with a polyhydramnion of the recipient and b oligohydramnios of the donor. Source: Arbeitsgemeinschaft der Wissenschaftlichen Medizinischen Fachgesellschaften e.V (AWMF). Leitlinie zur Überwachung und Betreuung von Zwillingsschwangerschaften. Online: https://www.awmf.org/leitlinien/detail/ll/015-087.html; Stand: 05.10.2020. [rerif]
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Fig. 6a Sagittal visualization of a TRAP fetus, b visualization of retrograde blood flow in the TRAP fetus. Source: Arbeitsgemeinschaft der Wissenschaftlichen Medizinischen Fachgesellschaften e.V (AWMF). Leitlinie zur Überwachung und Betreuung von Zwillingsschwangerschaften. Online: https://www.awmf.org/leitlinien/detail/ll/015-087.html; Stand: 05.10.2020. [rerif]
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Fig. 7 Diagnostic algorithm for monochorionic-diamniotic twins with discordant findings. Source: Arbeitsgemeinschaft der Wissenschaftlichen Medizinischen Fachgesellschaften e.V (AWMF). Leitlinie zur Überwachung und Betreuung von Zwillingsschwangerschaften. Online: https://www.awmf.org/leitlinien/detail/ll/015-087.html; Stand: 05.10.2020. [rerif]
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Fig. 8 Three-dimensional ultrasound image of a cephalopagus at 10 weeks of gestation. Source: Arbeitsgemeinschaft der Wissenschaftlichen Medizinischen Fachgesellschaften e.V (AWMF). Leitlinie zur Überwachung und Betreuung von Zwillingsschwangerschaften. Online: https://www.awmf.org/leitlinien/detail/ll/015-087.html; Stand: 05.10.2020. [rerif]
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Abb. 1 Ultraschallbilder im ersten Trimester von a einer dichorial-diamnialen Zwillingsschwangerschaft, bei welcher die Zwillinge durch eine dicke Schicht fusionierter Chorionmembranen getrennt sind und b einer monochorial-diamnialen Zwillingsschwangerschaft, bei welcher die Zwillinge nur durch 2 dünne Amnionmembranen getrennt sind. Quelle: Arbeitsgemeinschaft der Wissenschaftlichen Medizinischen Fachgesellschaften e.V (AWMF). Leitlinie zur Überwachung und Betreuung von Zwillingsschwangerschaften. Im Internet: https://www.awmf.org/leitlinien/detail/ll/015-087.html; Stand: 05.10.2020. [rerif]
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Abb. 2 Algorithmus des Ultraschallmonitorings (vollendete Schwangerschaftswochen) für unkomplizierte dichoriale Zwillingsschwangerschaften. Quelle: Arbeitsgemeinschaft der Wissenschaftlichen Medizinischen Fachgesellschaften e.V (AWMF). Leitlinie zur Überwachung und Betreuung von Zwillingsschwangerschaften. Im Internet: https://www.awmf.org/leitlinien/detail/ll/015-087.html; Stand: 05.10.2020. [rerif]
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Abb. 3 Algorithmus des Ultraschallmonitorings (vollendete Schwangerschaftswochen) für unkomplizierte monochoriale Zwillingsschwangerschaften. DVP = deepest vertical pocket (tiefster vertikaler Fruchtwasserpool); PI = pulsatility index (Pulsatilitätsindex); MCA-PSV = peak systolic velocity (Vmax der A. cerebri media); A. umb = Arteria umbilicalis; MCA = middle cerebral artery (Arteria cerebri media); EFW = estimated fetal weight (geschätztes Fetalgewicht). Quelle: Arbeitsgemeinschaft der Wissenschaftlichen Medizinischen Fachgesellschaften e.V (AWMF). Leitlinie zur Überwachung und Betreuung von Zwillingsschwangerschaften. Im Internet: https://www.awmf.org/leitlinien/detail/ll/015-087.html; Stand: 05.10.2020. [rerif]
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Abb. 4 Klassifikation der selektiven fetalen Wachstumsrestriktion bei monochorialen Zwillingsschwangerschaften. Bei Typ I weist die Wellenform der Umbilikalarterie einen positiven enddiastolischen Fluss auf, während bei Typ II ein persistierender abwesender oder reverser enddiastolischer Fluss vorliegt (AREDF). Bei Typ III liegt ein zyklisches/intermittierendes AREDF-Muster im Wechsel mit positivem Fluss vor. Quelle: Arbeitsgemeinschaft der Wissenschaftlichen Medizinischen Fachgesellschaften e.V (AWMF). Leitlinie zur Überwachung und Betreuung von Zwillingsschwangerschaften. Im Internet: https://www.awmf.org/leitlinien/detail/ll/015-087.html; Stand: 05.10.2020. [rerif]
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Abb. 5 Sonografische Darstellung eines TTTS mit a Polyhydramnion des Rezipienten und b Oligohydramnion des Donors. Quelle: Arbeitsgemeinschaft der Wissenschaftlichen Medizinischen Fachgesellschaften e.V (AWMF). Leitlinie zur Überwachung und Betreuung von Zwillingsschwangerschaften. Im Internet: https://www.awmf.org/leitlinien/detail/ll/015-087.html; Stand: 05.10.2020. [rerif]
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Abb. 6a Sagittale Darstellung eines TRAP-Fötus, b Darstellung des retrograden Blutflusses im TRAP-Fötus. Quelle: Arbeitsgemeinschaft der Wissenschaftlichen Medizinischen Fachgesellschaften e.V (AWMF). Leitlinie zur Überwachung und Betreuung von Zwillingsschwangerschaften. Im Internet: https://www.awmf.org/leitlinien/detail/ll/015-087.html; Stand: 05.10.2020. [rerif]
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Abb. 7 Diagnostischer Algorithmus bei monochorial-diamnialen Zwillingen mit diskordanten Befunden. Perz. = Perzentile. *[44], **[32], ***[50]. Quelle: Arbeitsgemeinschaft der Wissenschaftlichen Medizinischen Fachgesellschaften e.V (AWMF). Leitlinie zur Überwachung und Betreuung von Zwillingsschwangerschaften. Im Internet: https://www.awmf.org/leitlinien/detail/ll/015-087.html; Stand: 05.10.2020. [rerif]
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Abb. 8 Dreidimensionale Ultraschalldarstellung eines Cephalopagus in der 10. Schwangerschaftswoche. Quelle: Arbeitsgemeinschaft der Wissenschaftlichen Medizinischen Fachgesellschaften e.V (AWMF). Leitlinie zur Überwachung und Betreuung von Zwillingsschwangerschaften. Im Internet: https://www.awmf.org/leitlinien/detail/ll/015-087.html; Stand: 05.10.2020. [rerif]