CLINICAL MEASURES OF GESTATIONAL-AGE IN NORMAL PREGNANCIES

Abstract

Obstetric findings in 89 healthy women were evaluated prospectively by 1 obstetrician unaware of menstrual history. With weekly examinations, fetal heart tones were audible by fetoscope at 17.1 .+-. 1.1 wk gestation (mean .+-. SD) and the fundus reached the umbilicus at 16.6 .+-. 0.9 wk. At 20-31 wk, fundal height in centimeters equaled weeks gestation (confidence interval: .+-.3 wk). The accuracy of predicting delivery date from combined finding (SD: 11.4 days) approached that from reliable menstrual history (SD: 10.2 days). Gestational age at delivery minus the pediatric Dubowitz estimate was 0.4 .+-. 1.7 wk. Gestational age may be overestimated by up to 6 wk by assuming that the fundus reaches the umbilicus or that fetal heart tones appear at 20 wk. Carefully derived obstetric estimates potentially may be more reliable than pediatric estimates.