Outcome of Prenatally-Detected Fetal Ventriculomegaly

Fetal ventriculomegaly (FVM) is a commonlydetected 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 IIIpregnancies 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 followup 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