Objective This study aims to determine the incidence, aetiology, diagnostic criteria and early outcomes of prenatally diagnosed fetal ventriculomegaly (VM).

Methods Diagnostic criteria for the fetal VM was atrial diameter of lateral ventricle measuring ≥ 10 mm, independent from gestational age. Results of our patients from ultrasonography (USG), karyotyping, congenital infections, and associated abnormalities were noted. Progress during pregnancy, postnatal USG results and outcomes after birth were recorded.

Results In our study, 40 cases of fetal VM were recorded. Female to male fetus ratio was (19/21) 0,90. Median gestational age at detection of VM was 22 weeks (ranging between 16–34 weeks). Sixteen of the 40 VM cases were bilateral (40%), 24 of the 40 VM cases were unilateral (60%). Twenty-one VM cases were isolated (52.5%), there were associated structural abnormalities in 19 of the 40 VM cases (47.5%). One case was complicated by toxoplasmosis (1/40) (2.5%). Nineteen of the 40 VM cases had amniocentesis (47,5%) and 2 of them showed abnormalities (10.5%). Twenty four of the 40 VM cases were improved and returned to normal during pregnancy (60%). Eight pregnancies were terminated (8/40) 20%). Three babies passed away during neoanatal and postneonatal period. Six babies classified in our mild "isolated" VM class were found to have some structural abnormalities after birth.

Conclusions Our report revelaed that associated abnormality incidence and termination rate among mild VM cases were high. Although most of mild VM cases are thought to be benign, associated abnormalities should be carefully evaluated and determined pre- and postnatally.