Acceleration and plateau: two patterns and outcomes of isolated severe fetal cerebral ventricular dilation.

OBJECTIVES

We sought to characterize patterns of in utero dilation in isolated severe fetal ventriculomegaly (ISVM) and investigate their value in predicting obstetrical and postnatal outcomes.

METHODS

This is a retrospective cohort study. ISVM was defined as a sonographic cerebral ventricle atrial with width ≥15 mm in the absence of additional cerebral or other anatomic anomalies. The aim of this study was to characterize two ISVM groups using a receiver operator curve to evaluate the rate of ventricular progression versus need for ventriculoperitoneal (VP) shunt postnatally. Outcomes were compared between the groups using Pearson's chi-squared test, Student t-test, and descriptive statistics.

RESULTS

Based on the ROC analysis, ventricular growth of ≥3 mm/week versus <3 mm/week distinguished fetuses likely to require a postnatal VP shunt. Fetuses were characterized as accelerators if ventricle growth was ≥3 mm/week at any point and plateaus if <3 mm/week. Accelerators showed a greater average rate of ventricle progression than plateaus (4.1 vs. 1.0 mm/week, respectively, p = .031) and were more likely to be delivered at earlier gestational ages (34.7 vs. 37.1 weeks respectively, p = .02). Ninety percent of accelerators demonstrated a need for shunt placement compared with 18.8% of plateaus (p < .001). Significantly more plateaus (87.5%) underwent a trial of labor while accelerators were more likely to have planned cesareans (70%, p = .009).

CONCLUSIONS

This study characterizes ISVM into two distinct populations based upon the rate of ventricle expansion, differentiated by the need for postnatal shunting. Once a ventricular growth pattern is determined, these distinctions should prove useful in prenatal management and delivery planning.