Prediction of birthweight by the use of extrauterine measurements during labor.

Maternal height, pregravid weight, weight gain during pregnancy, fundal height, McDonald's measurement, uterine width, uterine height, abdominal girth, and station of the fetal head were measured in 44 laboring, nulliparous women and were used to construct a regression model for the prediction of infant birthweight during labor. A model constructed from maternal height, weight gain during pregnancy, fundal height, abdominal girth, and station accounted for 69.6% of the variance in birthweight. The use of this regression equation resulted in predictions that were within 100, 250, and 500 gm of the actual birthweights in 34.1%, 79.5%, and 97.7% of the 44 cases, respectively. In all 44 cases, the weights of the infants also were estimated by palpation of the maternal abdomen during labor. These estimates were within 100, 250, and 500 gm of the actual birthweights in 31.8%, 61.4%, and 88.6% of the cases, respectively.