Biparietal/transverse abdominal diameter ratio <= 1: potential marker for open spina bifida at 11-13-week scan

摘要

Objective In the first trimester of pregnancy, a biparietal diameter (BPD) below the 5th percentile is a simple marker that enables the prenatal detection of half of all cases of open spina bifida. We hypothesized that relating the BPD measurement to the transverse abdominal diameter (TAD) might be another simple and effective screening method. In this study we assessed the performance of using the BPD/TAD ratio during the first trimester of pregnancy in screening for open spina bifida.