Progestin-primed ovarian stimulation (PPOS) is a new ovarian stimulation regimen for in vitro fertilization (IVF), with the advantages of an oral administration route and more control over preovulatory luteinizing hormone (LH) levels. Assessing the safety of this novel regimen is an important premise for its routine practice.We conducted a large retrospective cohort study for infants born between August 2014 and April 2017 from IVF and embryo transfer cycles after either PPOS and the conventional gonadotropin-releasing hormone-agonist (GnRH-a) short protocol at our center. Around 1589 live-born infants were finally enrolled, corresponding to 1258 frozen-thawed (FET) cycles, which led to 855 live-born infants from PPOS (659 FET cycles) and 734 live-born infants from the short protocol (599 FET cycles).Birth characteristics regarding gestational age, birth weight and length, infant sex, and early neonatal death were comparable between the 2 groups. The incidence of live-birth defects in the PPOS group (1.52%) was similar to that in the short protocol group (1.63%) and was not statistically significant. For birth defects, the risk significantly increased for multiple births, and the adjusted odds ratio was 3.14 (95% confidence interval [CI]: 1.25-7.88). No associations were found between congenital birth defects and maternal age, body mass index (BMI), the duration of infertility, method of insemination, infant sex, embryo stage at transfer, the number of embryos transferred or ovarian stimulation regimen.Our study shows that the neonatal outcomes and risk of congenital malformations were similar between the PPOS and conventional GnRH-a short protocol. However, multiple pregnancy led to a higher likelihood of birth defects.