Frequency of Ultrasonographically Detectable Fetal Anomalies in Known Oligohydramnios Pregnancies

Background: The amniotic fluid protects and cushions the developing baby. Reduced amniotic fluid, or oligohydramnios, is linked to a higher rate of birth defects. Objective: To find out the frequency of ultrasonographically detectable fetal anomalies in pregnancies complicated by oligohydramnios. Study Design: Cross sectional study. Settings: Department of Diagnostic Radiology, University of Child Health Sciences (UCHS), Children Hospital, Lahore Pakistan. Duration: 6th October 2020 to 5th April 2021. Methods: A total of 173 women 19 to 40 years old having oligohydramnios during their second or third trimester of pregnancy were included. Patients with multiple gestation and intrauterine fetal death were excluded. They were scanned in detail with ultrasound machine having a convex 3.5 MHz probe for the severity of Amniotic Fluid Index (AFI) and for congenital fetal anomalies. Patients’ demographics and clinical characteristics were recorded. Results: Age range in this study was from 19 to 40 years with mean age of 27.8±5.1 years. Majority of the patients 144(83.23%) were between 25 to 35 years of age. Among pregnancies complicated by oligohydramnios, 39(22.54%) were reported to have ultrasonographically identifiable foetal abnormalities. Among the females, 58 (33.52%) had a vaginal delivery, while 115(66.47%) underwent a cesarean delivery. Still births observed in 7(4.04%), fetal renal tract anomalies 17(9.82%), fetal distress 13(7.51%), musculoskeletal anomalies 11(6.35%), cardiac anomalies 5(2.89%), central nervous system anomalies 6(3.46%), gastrointestinal anomalies 13(7.51%) hydronephrosis 6(3.46%), hydrocephalus 4(2.31%), meningocele 3(1.73%), diaphragmatic anomalies 5(2.89%) and hernias was noted in 8(4.62%) females. Lastly, multiple congenital anomalies were identified in 17(9.82%) cases. Conclusion: This study concluded that frequency of ultrasonographically detectable fetal anomalies in pregnancies complicated by oligohydramnios is quite high.