Fetal weights and measurements as determined by postmortem examination and their correlation with ultrasound...

Two hundred fifty fetuses from healthy singleton pregnancies terminated other than on health grounds at 21 to 26 weeks gestation were examined by ultrasound in utero and by autopsy. No significant maturational difference between male and female fetuses was noted, although larger biparietal distances (0.2 cm) and smaller femur lengths (0.2 cm) were seen in female fetuses at 23 weeks gestation, and heavier body weights were also noted (80 g). No maturational difference was noted between white and nonwhite populations. Maternal age was not a significant variable. Organ weights and fetal anthropometric measurements are provided. Biparietal diameter as determined by ultrasound examination of the fetus in utero is an excellent predictor of gestational age and correlated well with actual caliper measurements on the fetus (coefficient of variation [CV] < 5%). Femur length determined by ultrasound examination of the fetus in utero is significantly low compared with actual length (CV = 23%) and is not a reliable indicator of fetal development. A large CV (17%) was also seen for calculated fetal weight.