Borderline oligohydramnios in singleton pregnancies with intact fetal membranes in the third trimester: obstetric management and perinatal outcome

Aim To examine the attitude of the obstetricians and the perinatal outcome of pregnancies complicated by borderline oligohydramnios in the third trimester. Borderline oligohydramnios was defined as an AFI between 5 and 10. Methods 24 singleton pregnancies with borderline oligohydramnios without history of ruptured amniotic membranes or congenital fetal malformations were included. The patients were hospitalised for various reasons in the antenatal ward. Initial ultrasound assessment of the pregnancy happened shortly after admission. The fetal-placental circulation as assessed with umbilical artery Doppler was normal. No patients had invasive karyotype testing. The patients were divided in two groups depending on whether the borderline oligohydramnios was isolated (37, 5%) or associated with other pregnancy complications or risk factors (62, 5%). Results Increased obstetric interventions (induction of labour, Caesarean section) occurred in our study. Particularly in the cases of borderline oligohydramnios associated with other complications or risk factors the rate of Caesarean section approached 87%. 44% was the Caesarean section rate in the cases of isolated borderline oligohydramnios. The perinatal outcome was good especially after 34 weeks. There were no perinatal deaths or major perinatal morbidity. Two neonates born before the 34th week of gestation were admitted to neonatal intensive care unit. Conclusion Meticulous surveillance of the pregnancy and increased intervention follows the finding of borderline oligohydramnios. The perinatal outcomes appear satisfactory. Are such perinatal outcomes feasible without a cascade of obstetric intervention?