Evolution of fetal ventricular dilatation in relation to severity at first presentation

Background: To assess the outcome of 360 cases of fetal ventriculomegaly in a tertiary referral center.

Methods: Cases of fetal ventriculomegaly between June 1993 and December 2011 were identified from the departmental fetal database. The fetal medicine reports and obstetric notes were reviewed to ascertain the antenatal progression of the ventriculomegaly as well as the outcome of the pregnancy. Ventriculomegaly was defined by a lateral ventricular wall atrial measurement of greater than 10 mm. Cases were subdivided into mild (>10 to <12 mm), moderate (≥12 to <15 mm), and severe (≥15 mm). Termination of pregnancy was offered in cases where there were associated anomalies, aneuploidy, or the ventriculomegaly progressed.

Results: Of the 360 cases, 189 were mild, 79 were moderate, and 92 were severe. Sixty-four percent of cases had associated anomalies. Forty-six percent of cases in the mild group and 26% in the moderate group resolved. Only one case in the severe group improved. The mean rate of progression in the mild group was 1.07 (SD 1.03) mm/week, whereas in the moderate group progression was at a mean rate of 1.41 (SD 0.77) mm/week. Progression of severe ventriculomegaly was significantly higher at a mean rate of 3.26 (SD 2.92) mm/week (p = 0.007).

Conclusions: The majority of fetuses with mild ventriculomegaly normalized, whereas the majority of moderate cases remained stable. The rate of progression of ventriculomegaly increased with severity. Fetuses with ventriculomegaly should be offered serial scans to allow the progression of ventriculomegaly to be ascertained with the option of late termination of pregnancy.