[Normal development of the lateral ventricle of the fetus--study of improved early detection of fetal hydrocephalus].

The widths of foetal lateral ventricles and hemispheres were measured in 197 normal pregnancies in addition to routine ultrasound foetometry between the 12th and 40th weeks of gestation. The 95% confidence intervals of foetal lateral ventricle hemisphere ratios were calculated by means of regression analysis. The mean value for the occipital horn hemisphere ratio was 0.57 in the 12th week of gestation and 0.21 in the 40th week of gestation. The mean value of frontal horn hemisphere ratio was 0.41 in the 12th week of gestation and 0.18 in the 40th week of gestation. Values exceeding the upper limit of 95% confidence interval are indicative of early development of foetal hydrocephalus and should be followed by further foetal investigations.