Accuracy of ultrasonic age determination and weight prediction in the fetus with preterm premature rupture of membranes

ABSTRACT

Ultrasonic gestational age determination and fetal weight prediction were performed in 20 patients with preterm premature rupture of the membranes [PPROM], and 10 normal gravides with intact membranes, between the 28th and less than 37 weeks of gestation, to assess of the effect of PPROM on the accuracy of ultrasonic age estimation and fetal weight prediction.All gravides had known menstrual age, and delivered within 24 hours of ultrasonic examination, and the actual birth weight was determined. Using single parameter for gestational age assessment [bipartietal diameters, abdominal circumference or femur length], the bipartietal diameters was the least reliable, as there was significant difference in the mean error between the control and studied groups [p<0.05]. Multiple parameters formulas for gestational age estimation [HC, FL;HC, FL, AC; and HC, FL, BPD, AC], did not appear to add further accuracy to single parameters methods. Using three questions for prediction of fetal weight [BPD, AC, MAD, BPD, FL; and HC, AC, FL], we have found no significant difference in the mean error percent between the control and studied groups. Neither amniotic fluid volume, duration of membrane presence or absence of labor pains affected the accuracy of ultrasonic estimation of gestational age or prediction of fetal weight. It is concluded that PPROM appears to have no deleterious effect on the accuracy of ultrasonic estimation of gestational age and prediction of fetal weight, except when the BPD is used as a single parameter for age estimation