Prenatal diagnosis P11Fetal scanning between 18 and 22 weeks is passé

Abstract

Our study summarizes about 40000 early transvaginal examinations (14–16 weeks gestation). There were more than 1200 anomalous fetuses which demonstrated more than 1700 anomalies. We analysed the anomalies according to (1) early onset anomalies, (2) transient anomalies which disappeared toward the second trimester (nuchal findings, echogenic bowel, hypospadias., etc.), (3) anomalies which are much more easily detected in early pregnancy (vascular ring, rt. aortic arch, coarction, finger anomalies, kidney anomalies and others), (4) abnormalities which appear or manifest only in late pregnancy (lissencephalos, achondroplasia, etc.).ConclusionsThe percentage of late onset abnormalities is lower than for transient abnormalities. Therefore, performing only one examination by an expert will detect 97% of the detectable abnormalities in early pregnancy. Performing only one examination between 18 and 22 weeks will reveal a lower rate of the detectable anomalies. Most of the late onset anomalies appear later than the 22rd week of gestation. Therefore, the 18–22 week scan is passé and should give way to the 14–16 week TVS scanning in the search for fetal anomalies.