Use of low-dose human chorionic gonadotropin (hCG) for final follicular maturation in ovulatory women treated by intrauterine insemination

Objective: To evaluate follicle growth and maturation supported by daily late follicular phase low-dose human chorionic gonadotropins (hCG) administration following pre-stimulation with clomiphene citrate(CC) and human menopausal gonadotropin (hMG) in comparison with a sequential CC and hMG regime only.
Materials and methods: A prospective controlled randomized trial. Sixty infertile women who were considered suitable for intrauterine insemination (IUI) were recruited. All of the patients received 100mg dose of CC for 5 days (Day 3-7 of their cycle) with hMG from day 8. Then the patients were assigned to two groups. Thirty patients received low-dose hCG (250 IU/day, group A) when a leading follicle greater than 14mm in diameter was detected in serial transvaginal ultrasound. Thirty patients (group B) continued only hMG. In both groups, hCG (10/000 IU IM) was given when the leading follicle diameter reached 18-20mm.
Results: The mean age, BMI, duration and cause of infertility were similar in both groups. Group A had significantly more follicles above 14mm (p = 0.035) and significantly fewer follicles below 14mm by the end of the stimulation compared with group B (p = 0.045). A significantly higher in serum estradiol (E2, pg/ml) on the day of hCG administration was observed in group A (368.5±40 vs. 194.2±10 in group B, p = 0.015). There was no difference in the endometrial thickness between the groups (10.3 ± 2.3, group A vs. 10.5 ± 2.8, group B). There were significantly more chemical and clinical pregnancies in group A (26% vs. 10%, p = 0.02). No pregnancy miscarried and there were two twin pregnancies in group A and one in group B. Two of the pregnancies in group B developed moderate forms of ovarian hyperstimulation syndrome (OHSS) and none in group A.
Conclusions: The use of micro-dose HCG after gonadotropin therapy in the late follicular phase is better at achieving pregnancies than a conventional regimen.

Keywords
Ovarian stimulation, low-dose human chorionic gonadotropin (hCG), intrauterine insemination (IUI)