Comparison of the Efficacy of Letrozole and Clomiphene in Promoting Ovulation in PPOS Inpatients with Poor Ovarian Response

OBJECTIVE To compare the embryo laboratory and pregnancy outcomes between letrozole(LE) and clomiphene(CC) under progestin-primed ovarian stimulation(PPOS) in the patients with poor ovarian response(POR). METHODS A retrospective analysis was implemented among the POR patients who received PPOS and in vitro fertilization or intracytoplasmic sperm injection for pregnancy treatment in the reproductive center, the Second Affiliated Hospital of Wenzhou Medical University in November 2015 to July 2018. With a total of 544 cycles of PPOS, they were divided to group A(CC, 357 cycles) and group B(LE, 187 cycles) according to add CC or LE. The embryo laboratory and pregnancy outcomes were compared and analyzed between the two groups. RESULTS The estrogen level in group B was significantly lower than that in group A(P<0.05), but there was no significant difference in luteinizing hormone level and progesterone level on the trigger day. There were no significant differences in embryonic laboratory indexes such as available eggs number, mature egg number, number of cleavage, high quality embryo number, high quality embryo rate, egg maturity, embryo utilization rate, egg utilization rate and normal fertilization number, et al. The pregnancy outcomes such as clinical pregnancy rate, biochemical pregnancy rate and abortion rate were no significant difference between the groups. CONCLUSION The efficacy of adding LE or CC in the PPOS program of POR patients is equivalent, which can provide new insights for clinicians.