A longitudinal study of fetal growth variability

The aim of this study was to assess the variability in individual fetal gro wth rhythms in comparison to averaged standard curves obtained from cross-s ectional data. Biparietal diameter (BDP), abdominal transverse diameter (AT D) and femur length (FL) were measured by ultrasonography in 24 normal subj ects, and the variance in growth rates determined for four time intervals: 12-26, 26-34, 34-37 and 37-39 weeks gestation. BPD, ATD and FL growths were always linear until 26 weeks with low variances in growth rates. Growth ra tes decreased thereafter whereas related variances increased significantly with a great diversity in individual growth trajectories. This study questi ons the relevance of mathematically smoothed curves which lead to an errone ous impression of growth trajectory uniformity when ultrasonography does no t seem to be able to predict accurately newborn biometrical characteristics by the end of gestation. Copyright (C) 2000 S. Karger AG, Basel.