Role and effectiveness of progestins in pituitary suppression during ovarian stimulation for assisted reproductive technology: a systematic review and a meta-analysis

INTRODUCTION: Despite the many unknowns about its exact mechanism, progesterone and progestins are being successfully used to prevent luteinizing hormone (LH) surge during ovarian stimulation for assisted reproductive technology (ART). We will review progestin primed ovarian stimulation (PPOS) protocols in comparison with gonadotropin releasing hormone (GnRH) analogues and each other.EVIDENCE ACQUISITION: MEDLINE via PubMed; Cochrane Central Register of Controlled Trials (CENTRAL); Scopus; Web of Science were screened with keywords related to assisted reproductive technology, ovarian stimulation progesterone, GnRH analogue and progesterone in several combinations. Search period was from the date of inception of each database until 20 May 2022. EVIDENCE SYNTHESIS: Live birth or ongoing pregnancy rate per embryo transfer (ET) was similar in PPOS and GnRH antagonist cycles (RR=1.16, 95% CI: 0.93-1.44). Clinical pregnancy rate per ET was likewise similar (RR=1.12, 95% CI: 0.92-1.37). Miscarriage rate per pregnancy was similar with PPOS and GnRH antagonists in autologous cycles (RR=1.01, 95% CI: 0.65-1.55). Pooled analyses showed similar live birth rate between progestins and short GnRH agonist protocols (RR=1.01, 95% CI: 0.49-2.09), however, clinical pregnancy rates per ET were significantly higher with progestins (RR=1.31, 95% CI: 1.06-1.62). Miscarriage rate per pregnancy was similar with progestins (RR=0.82, 95% CI: 0.55-1.21).CONCLUSIONS: Progestins seem to be an efficient option for pituitary suppression during ovarian suppression, providing similar outcomes for stimulation and pregnancy. They can be especially beneficial for women for whom fresh ET is not considered.