Early detection of embryonic malformations by transvaginal and color Doppler sonography

A total of 834 women with uneventful pregnancies were followed prospectively until the 15th week of gestation by TVS to screen for early embryonic malformations. Twenty-eight embryonic anomalies were detected in this series (3.3%). The median gestational age at diagnosis was 11 (range, 8 to 15) weeks. Two neural tube defects were missed by early TVS screening. Two suspected abdominal wall defects were not confirmed by repeat mid-second trimester abdominal sonography representing 6.7% of all fetal malformations evident by 24 weeks of gestation. The sensitivity and specificity of TVS screening for fetal malformations in this series were 93.3 and 99.7%, respectively. In addition, the role of TCDU also was investigated in these 28 abnormal embryos. TCDU proved to be of limited value as it was useful only for evaluating those embryonic malformations with vascular involvement. In such cases, the diagnosis was greatly enhanced with this technique. Two previously undetected single umbilical arteries were also diagnosed by TCDU as well. This series included 11 aneuploid embryos (44%), most of them among the embryos with focal or generalized edema. This study demonstrates that screening for early embryonic malformations is feasible using TVS techniques, but a repeat mid-second trimester abdominal sonogram still is recommended.