Evidence that normal fetal growth can be noncontinuous.

Abstract

Fetal growth is presumed by current models to be continuous. We hypothesized that normal fetal growth is not continuous and that it demonstrates a pulsatile pattern. Fetal morphometric parameters were examined in 9 healthy women at an average interval of 2.7 days between 25 and 36 weeks gestation using an Acuson XP3 unit (Mountain View, CA) employing a 3.5 MHz curvilinear transducer. Parameters examined included biparietal diameter (BPD), abdominal circumference (AC), femur length (FL), and humeral length (HL). Mothers had normal prepregnancy weight, were nonsmokers, had normal glucose tolerance screening, and were without medical complications. Mean maternal age was 28.7 ± 5.8 years (S.D.) and mean maternal weight gain was 16.8 ± 3.3 kg. All neonates were born at term (range 39–42 weeks), without anomalies and a mean percentile birth weight at the 53rd centile (range 20–95th). Wald-Wolfowitz runs test was used to test for nonrandom patterns in the residuals from the fitted regression curve. When modeled ...