[Ventriculomegaly at the gestational age of 20 weeks; research into its incidence and related abnormalities].

Objective: To describe the incidence and the prognostic value of foetal ventriculomegaly identified between 18-23 weeks of gestational age in the northeastern part of the Netherlands during the 2002-2010 period.

Design: Retrospective cohort study.

Method: From the database of the University Medical Centre Groningen in the Netherlands, we selected all cases of singleton pregnancies in which ventriculomegaly was diagnosed at 18-23 weeks of gestation.

Results: In 2002, ventriculomegaly was diagnosed prenatally in 1:7000 foetuses; the incidence increased to 1:1750 in 2010. In 33 (51%) of 65 affected foetuses, an associated severe physical abnormality was detected, in 5 (8%) a subtle sonomarker (subtle ultrasound finding) and in 8 (12%), a chromosomal defect. In 47% of the pregnancies where ventriculomegaly was associated with other defects, the parents opted for termination of pregnancy. In the group with isolated mild ventriculomegaly (10-12 mm), termination was performed in 1 of 19 cases; and in the group with the greater ventricular width of 13-14 mm, this decision was made for 5 of the 8 pregnancies. All continued pregnancies of foetuses with isolated ventriculomegaly resulted in live births. Isolated ventriculomegaly was diagnosed relatively more frequently in male foetuses.

Conclusion: The introduction of ultrasound scans as part of standard prenatal care has resulted in an increased incidence of foetal ventriculomegaly. Important factors for predicting the outcome of the pregnancy are the degree of ventricular dilatation, the foetus' gender and the presence or absence of associated abnormalities. It is therefore important to use a standardised protocol for measuring ventricular width, record the biparietal diameter and foetal gender, perform a systematic physical examination and use karyotyping.