Effectiveness of minimal stimulation versus conventional GnRH antagonist protocols in controlled ovarian hyperstimulation: a retrospective analysis of 10769 IVF/ICSI cycles

BACKGROUND: The aim of this study was to find the efficacy of minimal stimulation protocol over antagonist protocol in infertile couples. METHODS: A total of 10769 patients who visited between January 2018 and January 2022 were included in this retrospective study. To reduce potential bias and baseline heterogeneity between the two groups, Propensity Score Matching was employed, so the data after propensity matching was N.=978. Group 1 - minimal stimulation group (N.=347) - received clomiphene citrate 100 mg along with gonadotropin (≤150 IU), either recombinant follicle-stimulating hormone (r-FSH) or human menopausal gonadotropin (hMG). Group 2, the conventional dose antagonist group (N.=631), received a conventional dosage of r-FSH (≥225 IU) as per institutional practice. RESULTS: The minimal stimulation group had a considerably higher live birth rate (58.20%) than the antagonist group (51.20%), with a P value of 0.035, demonstrating a statistically significant benefit for the minimal stimulation procedure. For live birth rate, endometrial thickness (odds ratio [OR] = 1.22, 95% confidence interval [CI]: 1.09-1.36, P<0.001), number of embryos transferred (OR=1.95, 95% CI: 1.37-2.78, P<0.001), and sperm count (OR=1.01, 95% CI: 1.00-1.05, P=0.044) were significant predictors. In the subgroup anti-Müllerian hormone (AMH; 1.5-2.5 ng/mL), the antagonist protocol yielded a significantly higher number of oocytes retrieved and mature oocytes; however, the minimal protocol demonstrated superior blastulation rates, good blastocyst quality, and a notably higher live birth rate. CONCLUSIONS: Compared to the standard treatment, the minimal stimulation group's live birth rate was much higher, indicating that some patient populations might benefit from fewer drugs and less stimulation.