Objective To evaluate the clinical significance and prognosis of tetus with lateral ventriculomegaly.Methods We retrospectively analyzed 92 singleton pregnant women who were antenatally diagnosed with fetal ventriculomegaly by ultrasound in genetic conselling clinics,Department of Gynaecology and Obstetrics,Nanfang Hospital,Southern Medical University between August 2007 and August 2010.All participants were divided into three groups according to the width of the lateral ventricles:group A (10.0-12.0 mm,n=50),group B (12.1-14.9 mm,n=38) and severe ventriculomegaly group (≥15.0 mm,n=4).All fetuses were followed up.Chi-square test(or Fisher's exact test),Bonfferoni method,Mann Whitney or Kruskal-Wallis test were used for statistics.Results In group A,B and severe ventriculomegaly group,18% (9/50),65.8%(25/38)and 3/4 of fetuses were complicated with structural malformation,respectively (x2 =22.934,P =0.000),and statistical significance were found only between group A and B (x2 =20.798,P=0.000).The incidences of fetal chromosomal aberration were 4.0% (2/50),7.9% (3/38)and 0/4 in the three groups,respectively (x2=0.878,P = 0.645).Eventually,all four cases with severe cerebral ventriculomegaly were terminated.Among cases of mild ventriculomegaly,63 women continued the pregnancy (48 in group A and 15 in group B).The intrauterine improvement of group B was poorerthan that of group A (Z=-3.317,P =0.001).Respectively,three,ten and two cases of ventriculomegaly deteriorated,stabilized and regressed in group B,and the corresponding figures were 3,15 and 30 in group A.In group A,the prognosis of fetus with non-isolated ventriculomegaly was poorer than that of fetus with isolated ventriculomegaly (Z=-2.631,P=0.009).For neonates 14 days after birth (n=62),the rates of normal neonatal behavioral neurological assessment (NBNA) scoring were respectively 93.8% (45/48) and 71.4% (10/14) for groups A and B with statistical difference (Fisher's exact test,P =0.040).Bayley scales of infant development (BSID) used to evaluate infants at 12-month-old revealed that the psychomotor developmental index (PDI) between group A and group B had statistical difference (8,26 and 1 case of good,moderate and poor development in group A; one,seven and three cases in group B; Z=-2.203,P=0.043).However,the mental developmental index (MDI) between group A and B had no statistical difference.Twenty babies among the survived ones received magnetic resonance imaging (MRI) examination.The results showed that lateral ventricle width regressed in nine babies (45.0%) and progressed in one baby (5.0%).Ten cases (50.0%) did not change.The change of ventriculomegaly after birth was related to BSID evaluation.Better prognosis of fetuses were found in those with regressed ventriculomegaly (P=0.033).Conclusions Fetuses with mild ventriculomegaly (10.0 12.0 mm) have a favorable outcome.Further investigations,such as fetal development,chromosomal examination,intrauterine infection screening and MRI if necessary,are suggested for fetus with ventriculomegaly.Moreover,intensive intrauterine and postnatal follow-up is recommended. Key words: Lateral ventricles ; Dilatation, pathologic ; Ultrasonography, prenatal; Prognosis