Oral sildenafil citrate: a potential approach for improvement of endometrial thickness and treatment of unexplained infertility in women

Objective: The study aimed to determine the impact of using sildenafil citrate as an adjuvant with clomiphene citrate (CC) in the treatment of women with unexplained infertility.
Patients and methods: 130 women with unexplained infertility were enrolled in a prospective randomized study. After dividing into two groups, all patients received CC 50 mg-BD from the 2nd to the 7th day of the cycle. Oral sildenafil citrate 20 mg was given BD to the study group from the end of menstruation till ovulation. A transvaginal ultrasound was carried out for all patients to assess ovulation, number of follicles, and endometrial thickness (ET). The beta-hCG blood test was used to determine pregnancy two weeks after ovulation followed by an ultrasound to confirm viability. Adverse effects were recorded and miscarriage, ectopic, and multi-fetal pregnancy were followed up for twelve weeks.
Results: Median ET in the study group was 8 mm compared to 7 mm in the control group (p<0.01). The number of pregnancies increased in the study group but with no significant difference. The median ET was greater in the study group with an infertility duration of less than 2 years. Headache was the most significant adverse effect in the study group (9.2% vs. 1.5%, p=0.052).
Conclusions: Adding sildenafil citrate to CC is a good choice for overcoming the antiestrogenic action of CC and improving ET in women with unexplained infertility, especially in those with less than 2 years of infertility.