Key words Arabin pessary - preterm birth - prevention - recommendations - placement - removal
- surveillance
Schlüsselwörter Arabin-Pessar - Frühgeburt - Prävention - Empfehlungen - Platzierung - Entfernung
- Überwachung
Introduction
In 2014, the German Society of Obstetrics and Gynecology (Deutsche Gesellschaft für
Gynäkologie und Geburtshilfe [DGGG]) formed an obstetrical task force (Arbeitsgemeinschaft
Geburtshilfe und Pränatalmedizin [AGG]) to promote the implementation of guidelines.
Recently, an S2-consensus guideline on the prevention and treatment of preterm birth
[1 ], [2 ] was published which included indications for the Arabin pessary. This position paper
adds important clinical recommendations on technical aspects such as pessary insertion
and removal as well as clinical and ultrasound surveillance recommendations for patients
receiving pessary treatment.
The Arabin pessary has been approved for the prevention of preterm birth in Europe
(CE0482/EN ISO 13485:2003 annex III of the council directive 93/42 EEC). In the US
and Canada, the pessary was given an FDA Investigational Device Exemption (IDE) and
Medical Device Investigational Testing Authorization, respectively, to permit its
use in studies [3 ]. Large trials and a prospective meta-analysis are being conducted worldwide. Clinical
use of the cerclage pessary, which may stay in the vagina for > 28 days, is regulated
by the Medical Device Regulation (MDR) which has legal implications within the European
Union [2 ].
The MDR demands that the manufacturer provides instructions including guidelines on
clinical use, labeling and warnings. These instructions must be followed by physicians
who should give concrete reasons in the patientʼs records (e.g., leave the pessary
in place in patients with premature rupture of membranes during transportation). This
paper has considered the most recent version of these instructions (Rev. 2018) and
additionally considered the answers to frequently asked questions (FAQs) provided
for physicians and patients in several languages by the manufacturer of the Arabin
pessary. Both are documented on the website [3 ], [4 ].
The instructions are revised by the medical team and the notifying body (MedCERT)
of the manufacturer on an annual basis based on completed studies and post-surveillance
procedures; the revisions are numbered. Since pessaries with instructions are sometimes
held in stock for a while, the latest versions can also be downloaded from the corresponding
website [3 ].
Clinical Items to Be Considered Before Pessary Application
Clinical Items to Be Considered Before Pessary Application
Size of the pessary
Multiple sizes of pessaries are available. The inner upper diameter of the Arabin
pessary, which surrounds the cervix, is usually 32 mm. Pessaries with an inner upper
diameter of 35 millimeters can be used in a wide cervix with funneling. The outer
lower diameter varies between 65 and 70 mm. The height of the available pessaries
is 17, 21, 25 and 30 mm. This allows physicians to take an individual approach and
adapt the choice to specific situations such as discomfort (shorter sizes), multiple
pregnancy or mild genital prolapse (larger sizes). Arabin and Alfirevic [4 ], [5 ] provide a guide to assist in size selection. Meanwhile, an app on the website [3 ] helps to choose the right sizes for different clinical situations.
In general:
The inner upper diameter should usually be 32 mm when treating average cervical shortening
and, in rare cases, 35 mm (in patients with an unusually edematous wide cervix or
U-shaped funneling) to avoid compression with further secretion of atypical interleukins
and cytokine production [5 ], [6 ].
The outer lower diameter should be 65 mm for nulliparous or women of small constitution
and 70 mm for multiparous or tall women.
The height of the curvature should be 17 mm in rate cases, possibly only during the
first trimester; otherwise the height should be 21 mm for singleton pregnancies and
smaller women, 25 mm for multiple pregnancy and taller women, rarely 30 mm in women
with a mild degree of genital prolapse.
These are patient-related features which can be modified to adapt to individual patients.
Pessaries are delivered with perforations of the silicone ring for the easier release
of vaginal discharge from the upper fornix of the vagina.
Statement
There is no absolute indication for a specific size. Different sizes allow an individual
approach according to the patientʼs characteristics.
Vaginal swabs and pH measurements
The indications for obtaining a vaginal or cervical sample do not differ from those
for other patients at risk of spontaneous preterm birth. This means that in patients
with a high risk for preterm birth, specific multi-resistant bacteria or streptococcus
should be excluded in a timely manner. Romero et al. stated that the vaginal microbiome
is not associated with the microbiome in the intraamniotic cavity or an inflammation
of the amniotic membranes, and not necessarily with preterm birth (PTB) [6 ], [7 ].
Consequently, systematic administration of antibiotics is not indicated and may be
harmful. Vaginal discharge is a common side effect of pessaries and should not be
treated with antibiotics. Vaginal pH measurements have never been evaluated in terms
of their sensitivity and specificity for detecting PTB and cannot be recommended before
or during pessary treatment.
Statement
Vaginal swabs or pH measurements are not necessary before pessary insertion and their
use should be restricted to specific indications, e.g. intraamniotic sludge. Antibiotic
therapy based solely on vaginal discharge is contraindicated.
Speculum examination
Patients with sonographic cervical shortening below the 25th, 10th, or 3rd centile
according to the ultrasound curves of Salomon et al. [7 ] may have an indication for pessary treatment [8 ].
Before insertion, a speculum examination is indicated in patients with a history of conization or trachelectomy,
a history of cervical lesions, a suspicion of uterus duplex with the possibility of
two cervices and in cases where it is difficult to interpret the findings of transvaginal
sonography (TVS). A pessary can be placed in any patient with sufficient cervical
tissue to hold the pessary, including patients who are status post cervical surgery.
During pessary treatment , a speculum examination is indicated in cases with discomfort and suspicion of dislocation,
vaginal bleeding as well as suspicion of premature preterm rupture of membranes (PPROM).
Statement
Speculum examination before insertion is indicated in mothers who are status post
cervical surgery or lesions and during pessary placement or treatment in patients
with discomfort, suspicion of dislocation, vaginal bleeding or PPROM.
Training
Similar to other treatment modalities, the success rates of pessary treatment increase
with the experience of the treating physician and/or department [8 ], [9 ].
The European Guidelines on Preterm Birth recommend proper and continuous training
in pessary placement [9 ], [10 ].
Pessary placement in technically difficult situations requires experience. Difficulties
may arise due to:
maternal size, anatomy, parity and culture
pre-existing cervical shortening/thickness, opening of the internal/external cervical
os
sensitivity to vaginal procedures including vaginismus, experience of discomfort or
pain
specific anatomic or obstetric situations (e.g. bicornuate uterus, placenta previa,
etc.)
the degree of genital prolapse or additional urinary incontinence
incidental or sudden occurrence of preterm contractions or bleeding during treatment
the degree and kind of discharge, differential diagnosis: PPROM/urinary incontinence
the degree of cervical edema before removal due to contractions/pressure
Statement
Adequate provider training is a prerequisite for pessary placement and treatment.
Cervical pessaries should only be applied by healthcare professionals who have been
trained in the pathophysiology and clinical symptoms of PTB syndrome, who are trained
in transvaginal ultrasound (TVS) and/or have participated in a training course.
Communication and Practical Items to Be Considered During Insertion of the Pessary
Communication and Practical Items to Be Considered During Insertion of the Pessary
Insertion
Communication is an essential part of treatment. The indication, evidence and most
common side effects such as vaginal discharge should be discussed with the patient.
Patients at risk of genital prolapse should know that the pessary might descend with
the cervix during pushing. In addition, patients should receive instructions on how
to proceed in case they are admitted to a hospital where doctors are not familiar
with the therapy. The size and charge number should be documented in the patientʼs
chart. Once the patient has been informed in detail and re-assured and the documentation
has been completed, the pessary can be inserted (with the patient usually in a semi-recumbent
position).
The pessary should be folded with the smaller diameter pointing upwards so that the
device can be directed towards the top of the posterior fornix. During insertion the
pessary stays folded until the upper vaginal fornix is reached; it is then gently
placed as high as possible with the smaller diameter completely around the cervix.
The anterior rim may be gently pushed towards the sacrum so that the cervix is rotated,
with the entire cervix engaged in the pessary. An easier and less painful insertion
can be achieved by covering the pessary with gel. After placement, the pessary should
not be “felt” by the patient. It is recommended that the patient stands up and reports
whether she feels discomfort or a reduction of pressure. In case of pain or discomfort,
the size and position of the pessary should be considered. After insertion of the
pessary, a sonographic evaluation may be performed to confirm proper placement.
All steps are demonstrated in an online video provided by Professor Alfirevic, Liverpool
UK: https://youtu.be/5x2g6Eg2f0o
Alternatively, [Fig. 1 ] depicts the QR code to be directly forwarded to this link.
Fig. 1 QR code for the video providing information on pessary insertion (https://www.youtube.com/watch?v=5x2g6Eg2f0o&feature=youtu.be ).
Statement
Informed patient consent and pessary education is essential prior to placement. The
pessary should be gently inserted with the smaller diameter facing upwards. Instruction
pamphlets from the pessary package should be given to the patient, and the size and
charge number be documented.
Clinical Items to Consider During Pessary Treatment and Removal
Clinical Items to Consider During Pessary Treatment and Removal
Clinical examination
In asymptomatic patients with a low risk for PTB (sonographic length over the 3rd
percentile), clinical examinations during the period of pessary treatment are used
to confirm placement. At the first visit after placement, it should be confirmed that
the cervix is still surrounded by the upper ring of the pessary. In follow-up visits,
a vaginal digital examination may suffice to determine the position of the pessary.
In patients with mild genital prolapse, the pessary and cervix may be smoothly redirected
towards the upper vaginal vault – even by the patient herself if she feels the device
after standing or pushing.
Ultrasound surveillance
During pessary treatment, TVS may be used to reconfirm the cervical length or to detect
funneling. The cervical length can increase or decrease during treatment. Similarly,
funneling may increase or decrease. It is recommended that the transducer is placed
“on the top of the pessary” and the upper cervical lip ([Fig. 2 ]) to avoid unnecessary manipulation and a change in the uterocervical angle with
further false-positive evaluation of the cervical length. This technique eliminates
the shadow of the pessary. Placing the transducer “in the pessary” as stated by Goya
et al. [10 ] is associated with a de-sacralization of the pessary and a change in the uterocervical
angle and consequently carries the risk of measuring the cervical length as too short.
Fig. 2 Placement of the transducer “on the top of the pessary” and the upper cervical lip.
Statement
In patients with a pessary, TVS can be used to measure the cervical length and width
of funneling during treatment. Placement of the transducer on top of the pessary avoids
de-sacralization, unnecessary manipulation and a false-positive result of TVS.
Removal
This chapter discusses pessary removal < 34 weeks, between 34 and 37 and after the
completion of 37 weeks.
Indications for preterm removal of a pessary < 34 weeks:
Patients with regular contractions which cannot be prevented by IV tocolytics
Severe vaginal bleeding
Proven premature rupture of membranes (PPROM)
Suspicion of chorioamnionitis (Triple I)
In cases with mild contractions and intact membranes, tocolytic treatment should be
started with the pessary in place to provide the necessary time for effective treatment
with corticosteroids.
If contractions persist, the pessary should be removed.
PPROM should be diagnosed with the aid of biochemical tests (cave: false-positive
results) and ultrasound. If PPROM is proven, there are a few exceptions when the pessary
should be left in place for a short time. This includes maternal transport to a perinatal
center or cases at the limit of fetal viability when any manipulation increases the
risk of more contractions. These patients should be carefully supervised by specialists.
Since an early diagnosis of Triple I, as defined in the most recent version of the
guideline, is difficult to establish, leaving the pessary in place should be the exception
after obtaining informed consent from the patient and documenting this procedure in
the patientʼs records.
> 34 weeks/<37 weeks
When a patient is admitted with regular painful contractions after 34 weeks of gestation,
the pessary should be removed.
≥ 37 weeks
The pessary should be removed at 37 weeks in all patients unless a cesarean delivery
is scheduled. In cases of cesarean delivery, removal may be postponed until the day
of the operation and should be performed following spinal anesthesia, before skin
incision. The device must be removed in symptomatic patients and patients with PROM.
Technical aspects
In practice, the pessary can be removed by inserting a finger between the cervix and
the upper or lower inner ring. Before removal, it is important to ensure that the
cervix is pushed back through the inner ring of the dome. Patients with mild cervical
edema should be informed that removal may be painful. In rare cases when the pessary
is stuck due to contractions, severe cervical edema or progressive genital prolapse,
it may be prudent to cut the pessary with episiotomy scissors instead of removing
the pessary under anesthesia or by force.
Following removal from the cervix, the device can be squeezed (similar to insertion)
and carefully removed.
Once the pessary is removed it should not be re-used since it is certified for single
use only.
Statement
The pessary should be removed in cases with proven PPROM. A pessary should routinely
be removed when no risk of PTB remains at 37 weeks of gestation. If the device is
stuck, it should be cut rather than removed by force, as this reduces the risk of
lesions to soft cervical tissue.
Any severe events associated with pessary use should be reported to the manufacturer.
To date, most claims were due to ignorance regarding the instructions or false handling.
If possible, the size and charge numbers should also be reported.
