Identification of second trimester screen positive pregnancies at increased risk for congenital heart defects

To examine whether second trimester biomarkers could be used to identify screen positive pregnancies at increased risk for congenital heart defects (CHDs) and measure the effect of using different biomarker cut points on the detection of CHDs and on the performance of predictive models.

Included were 19,402 pregnancies without chromosomal defects, which were screen positive for Down syndrome or other birth defects based on maternal serum measurements of alpha-fetoprotein (AFP), human chorionic gonadotrophin (hCG), and unconjugated estriol (uE3). Logistic regression models were built that compared biomarkers for CHD cases compared to controls.

CHD cases were more likely to be screen positive for trisomy-18, to have a nuchal fold (NF) >or= 5 mm, and/or to have an hCG multiple of the median (MoM) >or= 95th percentile in models that considered screen positive grouping. In models that did not consider screen positive grouping, cases were more likely to have a NF >or= 5 mm, an AFP MoM or= 75th percentile.

Along with NF, second trimester maternal serum biomarkers may be useful indicators for fetal and newborn evaluation for CHDs in screen positive pregnancies without identified chromosomal defects.