Amniotic fluid index and prolonged antepartum fetal heart rate decelerations.

Both prolonged fetal heart rate (FHR) decelerations and decreased amounts of amniotic fluid (AF) have been associated with adverse fetal outcome. To determine whether adverse outcome could be predicted by a quantitative assessment of AF in patients with prolonged FHR decelerations, we identified 97 consecutive pregnancies found during antepartum testing to have prolonged FHR decelerations. A four-quadrant AF index was measured concurrently in 92 of these 97 patients. Women with an AF index less than 2 cm had operative intervention for fetal distress in seven of 11 cases (64%), compared with 17 of 81 (21%) who had an index of 2 cm or more (P = .005). We conclude that in patients with a prolonged FHR deceleration during antepartum testing, the need for operative intervention for fetal distress is increased when oligohydramnios is present.