The effect of sildenafil on amniotic fluid volume in cases of borderline oligohydramnios in uncomplicated pregnancies: a randomized clinical trial.

Abstract Introduction:Low amniotic fluid volume and oligohydramnios is important issue during pregnancy and is associated with an increase in fetal and neonatal mortality and morbidity. Finding a solution to it can improve fetal and neonatal outcomes.Objective:The purpose of the present study was to evaluate the effect of sildenafil on oligohydramnios in uncomplicated pregnancies.Methods:A placebo-controlled randomized clinical trial was performed on women with oligohydramnios and gestational age of 30 to 37 weeks and singleton pregnancy. The eligible women were randomly assigned into two groups. In the intervention group, 25 mg oral sildenafil was prescribed every 8 hours in conjunction with intravenous hydration therapy with 2 liters isotonic solution (normal saline) infused within 4 hours and in the control group, placebo and hydration therapy similar to the intervention group was prescribed. Amniotic fluid volume was re-evaluated 24 hours after treatment. If at least a 20% increase in amniotic fluid volume was detected by ultrasound, the woman was discharged; otherwise, the above regimen was repeated again for the next 24 hours.Discharged patients continued to take sildenafil or placebo at the same dose and consumption of 2 liters of oral fluids per day up to 37 weeks or delivery each happened earlier. Fetal monitoring was performed using non stress test (NST) twice a week, biophysical profile, and amniotic fluid volume measurement once a week. Amniotic fluid volume and pregnancy and neonatal outcomes were compared in the two groups.Results:One hundred ninety women finished the study. There was no statistically significant difference between the two groups in terms of maternal age, body mass index (BMI), parity, live birth rate, gestational age before the intervention, amniotic fluid index, and the type of pregnancy; spontaneous or using assisted reproductive technology (ART). In undelivered women, after the intervention, the amniotic fluid index was significantly higher in the case group than the control group. The number of women, whose pregnancies continued after the third week of intervention, were higher in the sildenafil group.At the end of the sixth week after intervention, 40 women (42.1%) in the case group continued their pregnancies versus 5 women (5.3%) in the control group (P = 0.001). Cesarean section rate, neonatal intensive care unit (NICU) admission, abnormal cardiotocography, umbilical cord pH less than 7.2, and Apgar score of less than 7 in 5 minutes, were less in the intervention group than the control group. While the mean gestational age at birth and birth weight was higher in the intervention group than the control group. There was no perinatal death in both groups.Abnormal cardiotocography (CTG) (AOR= 6.3, CI95% 2.4-15.1, P< 0.001), cesarean section rate (AOR= 4.2, CI95% 2.1-8.9, P< 0.001), birth weight of less than 2500 gram (AOR= 3.3, CI95% 1.6-6.9, P= 0.001), gestational age at birth of less than 37 weeks (AOR= 3.2, CI95% 1.5-6.9, P= 0.009 ), Apgar score of less than 7 in 5 minutes (AOR= 2.6, CI95% 1.1-6.4, P=0.037), umbilical cord pH of less than 7.2 (AOR= 2.5, CI95% 1.9-6.9, P=0.064), and NICU admission (AOR= 2.5, CI95% 1.1-5.9, P=0.032) were more in the control group.The most common maternal complication in patients was headache (15.8 vs. 7.4%) and headache (12.6 vs. 5.3%) which was more in the intervention group than the control group, but not statistically significant.Conclusion:In pregnant women with oligohydramnios, sildenafil may be associated with better pregnancy outcomes.