Abstract
Fetal ventriculomegaly (FVM) is a commonly- detected anomaly in the second and third
trimester ultrasound scanning. Counseling in this situation is difficult, especially
when the chromosomal abnormalities have been excluded. An outcome data would be helpful
in counseling pregnant ladies with regards to future prognosis. A retrospective analysis
of records of patients presenting to our Genetic clinic with diagnosis of FVM (lateral
ventricular diameter ≥10 mm) or hydrocephalus was carried out from 1st January 2010
till 31st December 2014. Postnatal outcome information was obtained by telephonic
interviews with the parents. Of 109 cases identified in medical records, 33 were excluded
as they did not fit the inclusion criteria (either history of previous pregnancy or
child with hydrocephalus and ongoing pregnancy was unaffected, or with lateral ventricular
dilatation <10 mm at atrium). Seventy six cases fulfilled the criteria for enrolment.
Majority of the cases were detected between 18 and 26 weeks of gestation (62 %, range
14–35 weeks). The cases were divided into three groups: Group I—isolated mild VM (ventricular
dilatation 10–15 mm)—30 cases (39.5 %). Group II—isolated severe VM (ventricular dilatation
>15.0 mm)—13 cases (17.1 %). Group III—pregnancies with VM associated with other fetal
malformation or hydramnios on ultrasound or chromosomal abnormality—33 cases (43.4
%). Group III included both mild to moderate VM of <15 mm (17 cases, 53 % of this
group) and severe VM (16 cases, 47 % of this group). In Group III, both intracranial
and extracranial anomalies were observed. Central nervous system (CNS) abnormalities
included neural tube defects (seven cases), agenesis of corpus callosum (eight cases),
posterior fossa anomalies (six cases), and subdural hemorrhage in one case. Polyhydramnios
was the most frequent extracranial abnormality observed (seven cases). Absent nasal
bone was observed in two cases. Two cases of diagphragmatic hernia and one each with
associated uterine anomalies, and arthrogryposis along with hydrops were also seen.
Chromosomal studies (either FISH or karyotype or both) were performed, antenatally
or postnatally in 44 (57.9 %) of 76 cases. Abnormalities were detected in five cases
(11.3 %), all with aneuploidies (four cases of trisomy 21, one of Klinefelter syndrome).
Outcome survey was successful in 71 of 76 families. Overall, best outcome was observed
in Group I with isolated mild FVM. In 27 of 30 cases where a follow-up was available,
two pregnancies were terminated, one ended up in intrauterine death. Of remaining
24 children, 23 are doing very well postnatally; one child has moderate developmental
delay and failure to thrive. Overall, good outcome was obtained in 23/25 (92 %). Outcome
was worst in Group III where only three children are surviving of 13 pregnancies which
were continued. No child with age >6 months is doing well. In Group II, only two of
13 cases are alive, of whom, one is normal and another has increased head circumference
but no delay at five months. Outcome of other cases were: termination in eight, stillbirth
in one and lost to follow-up in two. Antenatal detection of FVM warrants more detailed
evaluation, because the prognosis depends upon the size, progression, as well as the
presence or absence of associated anomalies. Chromosomal studies are indicated. Generally,
isolated VM with left ventricular diameter <13–15 mm, having excluded chromosomal
disease with no prior history of VM, is associated with a good prognosis (92 % as
evidenced in the present study).
Keywords
Fetal ventriculomegaly - Hydrocephalus - Pregnancy - India
