ACCURACY OF INTRAPARTUM ESTIMATES OF FETAL WEIGHT - EFFECT OF OLIGOHYDRAMNIOS

OBJECTIVE: To study the effect of oligohydramnios on the accuracy of i ntrapartum clinical and sonographic estimates of fetal weight (EFWs). STUDY DESIGN: Intrapartum clinical and sonograph ic EFWs and an amniot ic fluid index (AFI) were obtained on 124 term patients. Oligohydramni os was defined as an AFI less than or equal to 5 cm. RESULTS: Clinical and sonographic. EFWs in women with oligohydramnios were significantl y less accurate than estimates derived in patients with normal amnioti c fluid: P=.03 and .02, respectively. The incidence of clinical and so nographic EFWs within +/- 10% of the actual birth weight were 70.1% an d 68.4%, respectively (P = NS). CONCLUSION In term patients, intrapart um sonographic prediction of birth weight offers no advantage over est imated fetal weight obtained by abdominal palpation. The presence of o ligohydramnios significantly reduces the accuracy of intrapartum clini cal as well as sonographic EFWs. Therefore, we suggest that intrapartu m EFWs be obtained prior to artificial rupture of the membranes.