Comparison of two gonadotropin-releasing hormone agonist suppression protocols for in vitro fertilization in young patients with low body mass index

Objective: To evaluate two different gonadotropin-releasing (pituitary downregulating) hormones used in in vitro fertilization (IVF) on the live birth rate in young patients with low body mass index (BMI) undergoing their first IVF cycle. Methods: In a retrospective study in a single public medical center, 555 long gonadotropin-releasing hormone agonist (GnRH-a) protocols were compared with 431 prolonged GnRH-a protocols between 2016 and 2018. All analyses were performed using the SPSS version 22.0. The primary measured outcome was live birth rate. Results: Compared with the long protocol, the prolonged protocol required more doses of gonadotropin and a longer duration of ovarian stimulation. Lower levels of serum luteinizing hormone and serum estrogen were detected on the day of chorionic gonadotropin administration, and a lower fertilization rate was found in the prolonged protocol. Although more oocytes were retrieved and more frozen embryos were recorded in the prolonged protocol, the live birth rate per fresh cycle was comparable between the two protocols (P = 0.057). The incidence of ovarian hyperstimulation syndrome was higher in the prolonged protocol group. In the subgroup of women with antral follicle count (AFC) of 12 or less, there was no difference in the live birth rate between the two protocols (P = 0.688). However, for women with AFC > greater than 12, the prolonged protocol was still a positive predictor of live birth rate. The odds ratio was 1.73 (95% confidence interval 1.04–2.89). Conclusion: The prolonged protocol might not increase the live birth rate in women with low BMI who are undergoing their first IVF cycle. However, for women with AFC greater than 12, a prolonged protocol could be a good choice to improve the live birth rate.