Improved Fetal Growth Associated With Maternal Rest in Fetuses Diagnosed With an Estimated Fetal Weight and an Abdominal Circumference Growth Velocity Less Than the 10th Percentile

Introduction Previous studies have demonstrated that fetuses with an estimated fetal weight (EFW) less than the 10th percentile with concomitant abdominal circumference (AC) growth velocity < 10th percentile are at increased risk for adverse perinatal outcomes. Material and Methods This was a retrospective case series of 104 fetuses who had a prior study in which the EFW was > 10th percentile and were identified with a subsequent EFW < 10th percentile with concomitant AC growth velocity between two examinations of < 10th percentile. The AC, head circumference (HC), and femur length (FL) growth velocity was computed as follows: [(AC, HC, FL EFW < 10th − AC, HC, FL EFW Previous Examination )/(weeks gestation EFW < 10th − weeks gestation EFW Previous Examination )]. Growth velocity 10th and 90th percentile reference values for the AC, HC, and FL, were derived from equations published from Intergrowth‐21st Project of longitudinal fetal growth protocol. Once abnormal growth was identified (EFW plus AC growth velocity < 10th percentile), the patients were asked to begin a course of complete maternal rest for 2 weeks, lying in the left lateral recumbent position. Following 2 weeks of maternal rest, the EFW percentile and the growth velocity of the AC, HC, and FL were reassessed as follows: Period 1: pre‐diagnosis of an EFW > 10th percentile versus EFW < 10th percentile; Period II: diagnosis of an EFW < 10th percentile versus 2 weeks following maternal rest. The velocity values were plotted on graphs and z ‐scores were computed. A p ‐value of < 0.05 was considered significant. Results For Period I, 100% ( N = 104) had an EFW and AC growth velocity < 10th percentile, 29% (30/104) a HC growth velocity < 10th percentile. Fifty‐four percent (56/104) a FL growth velocity < 10th percentile. Period II, which evaluated growth after 2 weeks of maternal rest, demonstrated the following significant findings ( p < 0.05): (1) increased EFW > 10th percentile (0% vs. 81%, 84/104); (2) increased AC growth velocity > 10th percentile (0% vs. 94%, 98/104); (3) increased HC growth velocity > 10th percentile (71%, 74/104 vs. 81%, 84/104), and FL growth velocity > 10th percentile (46%, 48/104 vs. 83%, 86/104). Conclusion Following maternal rest in fetuses with an EFW < 10th percentile and an AC growth velocity < 10th percentile, there was a significant increase in the EFW percentile as well as the AC, HC, and FL growth velocities.