Clinical and sonographic fetal weight estimates in active labor with ruptured membranes

To determine and compare the accuracy of clinical and sonographic estimates of fetal weight (EFW) in active labor with ruptured membranes.

Clinical and sonographic EFWs were obtained on 107 term patients in active labor, with cervical dilatation of 4 cm or more and ruptured membranes. Accuracy of birth weight was determined by calculating percentage error, absolute percentage error and ratio of estimates within 10% of actual birth weight for all stages of labor. Statistical analysis was by paired t test, Wilcoxon sign test, chi 2 test and Mann-Whitney U test; P < .05 was considered significant.

Absolute percentage errors were lower by the sonographic method at all stages. Except for the second stage of labor, the rates of birth weight +/- 10% were higher with the sonographic method than with the clinical method (83.17% vs. 60.75% and 84.9% vs. 63.44%, respectively). Estimations performed in the first stage were more accurate than in the second stage with both methods (absolute error of 7.82 +/- 5.5 vs. 12.38 +/- 4.9 for clinical and 5.44 +/- 5.99 vs. 9.08 +/- 3.19 for sonographic).

During active labor with ruptured membranes, sonographic EFWs are more accurate than clinical estimations. The accuracy of both methods is reduced during the second stage of labor.