Ovarian stimulation methods at a single-assisted reproductive technology institution: a retrospective study of successful outcomes

Aim: to examine an efficacy of various stimulation methods in a group of successful pregnancies.Materials and Methods. In a single center retrospective study 47 pregnancy cases were examined after performing embryo transfers at our institution from the years 2017 to 2021. Patients were divided into four groups: i) clomiphene hyperstimulation (CH), ii) stimulation with gonadotropin-releasing hormone (GnRH) agonist, iii) with GnRH antagonist, and iv) progestin-primed ovarian stimulation (PPOS). Age, anti-Mullerian hormone, presence of chronic disease, number of in-vitro fertilizations prior to conception, dosage of follicle stimulating hormone (FSH), presence of premature luteinizing hormone surge, number of egg retrievals, fertilization rate, and live birth rate were assessed.Results. The number of pregnancies obtained by CH, agonist, antagonist, and PPOS methods comprised 25, 12, 2, and 8 cases, respectively. No significant difference in parameters between CH group and non-CH groups, excepting FSH was observed. The FSH was used in CH group and non-CH group at dose of 1108 ± 468 IU and 1756 ± 394 IU, respectively (p < 0.0001).Conclusion. CH is not commonly used due to potential luteal phase defects, but it is thought to be cost-effective, requiring lower FSH doses, requiring no ovulation suppression antagonists, and exerting no effect on frozen embryos or fetuses. Hence, CH could be a suitable protocol for egg retrieval in Japan.