Biparietal diameter (BPD) growth rate between the first and second trimester as a predictor of poor obstetric and neonatal outcome among the Indian population

Background: The Objective of this study was to evaluate the association of BPD at 11-14 weeks and pregnancy outcome and to determine the role of incremental BPD growth from 11-14 weeks and 17-20 weeks in pregnancy outcome. Methods: Women (n=910) with singleton pregnancies were included in this prospective observational study after an early anomaly scan (11 to 14 weeks). Outcomes noted were the incidence of adverse events and the neonatal birth weight. Results: Irrespective of their original BPD at 11 to 14 weeks, fetuses had acquired optimum BPD growth rate on a follow up scan at 17-20 weeks, i.e., a majority of them fell in the 10th to 90th percentile group (P value < 0.001). Fetuses with BPD below the 10th percentile were small for gestational age (SGA) at birth despite an optimal growth rate. Also, a significant majority of the fetuses with BPD in the 10th to 90th percentile were Appropriate for Gestational Age (AGA) at birth. Conclusion: The BPD at 11 to 14 weeks scan predicts the incidence of SGA and AGA babies, independent of BPD growth rates between first and second trimester. The BPD growth rates were neither significantly different nor predictive of the birth weight or adverse pregnancy outcomes.