Publication:

A study on fetomaternal outcomes in term pregnancies with isolated oligohydramnios

Background Isolated oligohydramnios at term is still a matter of controversy among obstetricians, since there is conflicting evidence as to its effect on maternal and neonatal outcomes. The present study looked at the fetomaternal outcomes in term pregnancies which were complicated by isolated oligohydramnios.

Methods A prospective observational study was conducted among 350 pregnant women with singleton term pregnancies (37–40 weeks) diagnosed with isolated oligohydramnios (amniotic fluid index (AFI)≤8 cm) at a tertiary care hospital in Puducherry, India. Women with maternal and fetal comorbidities, congenital anomalies, pre-labour rupture of membranes or intrauterine fetal demise were excluded. Participants were followed from admission until delivery and 1st week of  neonatal period. The maternal, fetal and neonatal outcomes were analysed using SPSS version 21.0 and the associations between AFI and the obstetric outcomes were evaluated by means of appropriate statistical tests, taking p<0.05 as the criterion for significance.

Results The average age of the mothers was 26.8±4.2 years and the average gestational age at the time of admission was 38.4±1.1 weeks. Caesarean section was carried out in 53.4% of the women, fetal distress being the most common reason (33.1%). A non-reassuring non-stress test (NST) was noted in 23.4% of the pregnancies. 25.4% of the newborns required admission to the neonatal intensive care unit (NICU) and 15.4% had an Apgar score of less than 7 at five minutes. Meconium aspiration syndrome (13.7%) was the most common neonatal complication. Women who had severe oligohydramnios (with an amniotic fluid index of 0 to 5 cm) had a considerably higher rate of caesarean delivery than those with an AFI of 5.1 to 8 cm (73.2% versus 39.9%, p<0.001). Both a lower AFI and non-reassuring NST were significantly linked to caesarean delivery and to adverse neonatal outcomes.

Conclusions Though isolated oligohydramnios at term, there is higher need of obstetric intervention and poor perinatal outcomes that too when oligohydramnios is severe. Fetimaternal outcomes can be improved by early diagnosis by carrying out careful antenatal monitoring and by providing individualised obstetric care.