OC049: The diagnostic value of early malformation scan at 11 to 13 weeks

Abstract

To assess the diagnostic value of early malformation scan at 11 to 13 gestational weeks in a medium risk population. The study group consisted of 6489 singleton low-risk pregnancies examined 1998–2002 with a well known outcome of pregnancy. The median of maternal age was 35 years. Examination included screening for somatic anomalies, fetal echocardiography and the assessment of nuchal translucency for risk assessment of trisomy 21, 13 and 18 following the FMF criteria. The prevalence of major anomalies was 3.5% with a 1.3% frequency of major cardiac anomalies and a 2.1% frequency of chromosomal abnormalities. The detection rate of major anomalies up to 13 + 6 weeks was 77%. Termination of pregnancy following the diagnosis of severe anomalies was performed in 185 cases with 73% of these being done before 15 + 6 weeks. Women older than 34 years in 73% decided not to have invasive procedures. Examination of the fetus at 11 to 13 gestational weeks including early malformation scan, fetal echocardiography and the assessment of the nuchal translucency has the capacity to detect and also exclude a major part of severe abnormalities at an early stage of pregnancy, if properly done.