Perinatal Outcome with Isolated Oligohydramnios in Term Pregnancies: A Case-control Study from a District Hospital of Southern India

Introduction: Oligohydramnios is an abnormality of amniotic fluid which is one of the common complications during pregnancy and a threat to foetal development. Often it is associated with maternal risk factors like uteroplacental insufficiency, hypertension and preeclampsia which by themselves can affect perinatal outcome. Aim: To determine the perinatal outcome in isolated oligohydramnios with Amniotic Fluid Index (AFI) ≤5cm at term pregnancies. Materials and Methods: This was a hospital-based prospective case-control study done in Department of Obstetrics and Gynaecology at District Hospital Tumakuru, Karnataka, India, from January 2019 to July 2020. The study included two groups i.e, case group included 150 pregnant females with Amniotic Fluid Index (AFI) ≤5 cm and control group included 150 pregnant females with AFI range between 6-24 cm. After interview of all participants, all the information was entered in the proforma. All newborn babies birth weight, APGAR scores (Appearance, Pulse, Grimace, Activity, and Respiration) at 1st and 5th minute was recorded. Categorical outcomes were compared between the groups using Chi-square test. A p-value <0.05 was considered statistically significant. Results: The mean age was 23.16±3.09 years in case group and it was 23.42±2.99 years in control group, the difference of age between study group was statistically not significant (p-value=0.460). Abnormal doppler in 19.33% of cases versus 6% of controls (p-value<0.001). Non reactive Non Stress Test (NST) was seen in 46.67% versus 10.67% in control group (p-value<0.001). The foetal distress as a cause for caesarean section was seen in 64.8% cases group in comparison with 23.9% of control group. Low birth weight was found in 58.67% of cases versus 30% in control groups (p-value<0.001). Low APGAR scores (<7) were seen in 24.67% of case group versus 5.33% in control groups. The difference in the proportion of APGAR score at 5 minutes between study group was statistically significant (p-value<0.001) Neonatal intensive care unit admissions were seen in 42.67% of cases versus 12.67% in controls (p-value<0.001). Perinatal deaths was in 5.33% in cases versus 0.67% in controls (p-value=0.017). Conclusion: Isolated oligohydramnios was a significant risk factor during term pregnancies. Incidence of operative deliveries (instrumental vaginal delivery and caesarean section) is significantly increased in these patients with significant increase in perinatal morbidity and mortality.