Comparison of clinical estimation of fetal weight at the beginning and end of labor.

OBJECTIVE: To compare the accuracy of clinically estimated fetal weight (EFW) obtained at the beginning and end of labor. METHODS: The clinical EFWs obtained by obstetricians at the beginning (initial EFW) and end (repeat EFW) of labor were compared to determine the accuracy of the estimates in 138 women with term pregnancies. RESULTS: The initial clinical EFW was changed by obstetricians in 65% of patients over the course of their labor. There was a 66% chance that the repeat EFW was more accurate than the initial EFW (P=0.003). This increased to 78% when the difference between the initial and repeat EFW was more than 300 g (P=0.04). Duration and speed of labor, and change in fetal station were not correlated with a lower, higher, or more accurate EFW. CONCLUSION: The improved accuracy of a clinical EFW obtained at the end of labor is important for management decisions, such as whether to attempt operative vaginal delivery.