Role of Sildenafil in ovulation induction – A comparative study of outcomes with Sildenafil in ovulation induction cycles with Clomiphene Citrate

Background: Sildenafil causes vasodilatation by relaxing the smooth muscles of blood vessels. This enhances endometrial development, the health of which is indispensable for implantation and embryonic and fetal development. Aim: To assess the role of Sildenafil when used in ovulation induction cycles with Clomiphene Citrate (CC) with reference to Endometrial Thickness (ET), follicular development, Pregnancy rates and Side Effects. Materials and methods: In this prospective comparative study on 80 infertile women, we randomly divided them into two groups. In group A with 40 patients, ovulation induction with CC was given and in group B with 40 patients oral Sildenafil Citrate 25mg – BD, was added from Day 8 up to hCG trigger, in the CC induced cycle. A transvaginal ultrasound was done on Day 13 to assess follicular growth and ET. A urine β-hCG on Day 30 was done to detect pregnancy. Patients were followed up for 8 weeks to monitor miscarriages, ectopics and multi foetal gestation. Results: Mean ET at the time of hCG trigger was 9.64 in the Sildenafil group compared to 8.47 in group A without Sildenafil (p value 0.01). 65% of the patients in group B conceived with 3 cycles of ovulation induction compared to 42.5% who conceived in group A (p value 0.04). The mean of total number of follicles greater than 18 mm at hCG trigger was 1.62 and 1.91 in group A and B respectively (p – 0.09). Side Effects were significantly higher in group B with sildenafil compared to group A with CC alone (p – 0.006). Conclusions: As our study shows that use of Sildenafil improves ET and rates of conception, we recommend the routine use of Sildenafil in ovulation induction protocols.