Luteal-phase ovarian stimulation is feasible for producing competent oocytes in women undergoing in vitro fertilization/intracytoplasmic sperm injection treatment, with optimal pregnancy outcomes in frozen-thawed embryo transfer cycles

Abstract

To explore the feasibility of luteal-phase ovarian stimulation using hMG and letrozole in terms of ovarian response and pregnancy outcome using frozen-thawed embryo transfer. A prospective cohort study. Academic tertiary-care medical center. Two hundred forty-two female patients undergoing IVF/intracytoplasmic sperm injection (ICSI) treatment. Ovarian stimulation was initiated with hMG 225 IU and letrozole 2.5 mg daily after spontaneous ovulation. Letrozole administration was stopped when the dominant follicles reached diameters of 12 mm. Ovulation was induced with a GnRH agonist 100 μg when at least three follicles reached diameters of 18 mm or one dominant follicle reached 20 mm. The highest quality embryos were extracted and cryopreserved for later transfer. The primary outcome measured was the number of oocytes retrieved. Secondary outcomes were the clinical pregnancy rate, ongoing pregnancy rate, and implantation rate after frozen embryo transfer (FET) cycles. Of the 242 women enrolled in the study, all participants succeeded in producing oocytes and 227 women had highest-quality embryos to cryopreserve. The average number of oocytes retrieved was 13.1, producing an average of 4.8 highest quality embryos. Moreover, no cases experienced a premature LH surge or moderate/severe ovarian hyperstimulation syndrome during the stimulation cycles. In FETs, the clinical pregnancy rate, ongoing pregnancy rate, and implantation rate were 55.46% (127/229), 48.91% (112/229), and 40.37% (174/431), respectively. Of all the pregnancies in the study, 68 resulted in live births and 44 were ongoing. Luteal-phase ovarian stimulation is feasible for producing competent oocytes/embryos in women undergoing IVF/ICSI treatments, with optimal pregnancy outcomes in FET cycles.