Dual FSH and HCG Triggering Increases Clinical Pregnancy Rate in IUI for Unexplained Infertility: A Randomized Controlled Trial

Objectives: Despite advancements in the assisted reproduction technology (ART), the proportion of unexplained infertility is 30% among infertile couples. This study aimed to explore the pregnancy proportions in women with primary unexplained infertility who were given follicle-stimulating hormone (FSH) along with the human chorionic gonadotropin (hCG) trigger compared with those who were only given the hCG trigger. Materials and Methods: In this randomized controlled trial, the women eligible for intrauterine insemination (IUI) were investigated between April 1, 2022 and April 1, 2023 at Al-Zahra referral academic center. To this end, a total of 130 women were primarily screened and then 50 ones were excluded from the study based on the pre-defined inclusion criteria. Therefore, the final study population consisted of 80 eligible women with primary unexplained infertility, who were randomly assigned to the intervention group (n=40) and control group (n=40). The patients in the intervention group received two ampules (75 IU) of FSH in addition to two ampoules (5000 IU) of hCG, while the patients in the control group only received hCG. Both groups underwent IUI 34-36 hours after the hCG triggering. The biochemical and clinical pregnancy rates were evaluated as primary outcomes. Results: No significant differences were observed between the baseline and clinical characteristics, including endometrial thickness and the number of follicles before intervention (P>0.05). However, the clinical pregnancy rate was higher in the dual FSH and hCG group (40.0%, 16/40) than that in the hCG group (20.0%, 8/40) (P=0.048). The chemical pregnancy rates were 32.5% (13/40) and 37.5% (15/40) for the hCG and dual FSH and hCG groups, respectively. No significant relationships were detected between the biochemical pregnancy and the number of gestational sacs (P>0.05). Conclusions: The dual administration of FSH and hCG for oocytes, compared with the injection of hCG alone, improved the clinical pregnancy. The biochemical pregnancy and live birth rates as well as the number of gestational sacs were not improved significantly.