LONGITUDINAL MEASUREMENT OF AMNIOTIC-FLUID INDEX IN POSTTERM PREGNANCIES AND ITS ASSOCIATION WITH FETAL-OUTCOME

OBJECTIVE: Our purpose was to study the association between dynamic ch anges in serial amniotic fluid index measurements and adverse fetal ou tcome in postterm pregnancies. STUDY DESIGN: Serial amniotic fluid ind ex values were obtained semiweekly in 139 reliably dated, uncomplicate d, singleton pregnancies at > 41 weeks' gestation. Adverse fetal outco me was defined by the presence of moderate or thick meconium, fetal he art rate decelerations, cesarean delivery for fetal distress, neonatal intensive care unit admission, and perinatal mortality. RESULTS: Prom inent changes in the amniotic fluid index (i.e., > 50% increase or dec rease) had no association with adverse fetal outcome irrespective of r ate of change, provided the final value remained > 5.0 cm. A significa nt association with fetal heart rate decelerations and the presence of meconium was detected only in patients whose final amniotic fluid ind ex was less than or equal to 5.0 cm (p = 0.007 and p = 0.003, respecti vely). CONCLUSION: Irrespective of the rate of change in amniotic flui d index, postterm pregnancies are significantly associated with potent ial complications such as fetal heart rate decelerations and meconium staining when the final amniotic fluid index is less than or equal to 5.0 cm.