PURPOSE: Frozen embryo transfer (FET) is associated with increased maternal complications, but whether these risks are specific to the hormone replacement cycle (HRC-FET) protocol or shared broadly across FET pregnancies remains unclear. This study compared perinatal outcomes among non-ART, fresh embryo transfer, ovulatory-cycle FET (OC-FET), and HRC-FET pregnancies. METHODS: This was a single-center retrospective cohort study of 5417 singleton deliveries (2017-2025), comprising 4427 non-ART, 158 fresh embryo transfer, 208 OC-FET, and 624 HRC-FET pregnancies. Multivariable logistic regression, adjusted for maternal age, BMI, and parity, was used to calculate adjusted odds ratios (aORs), with non-ART as the reference group. RESULTS: Compared with non-ART, HRC-FET was associated with significantly increased risks of manual removal of the placenta (aOR 14.54), postpartum hemorrhage (aOR 2.33), and uterine atony (aOR 3.23). These risks remained significant after stratifying by mode of delivery. In contrast, fresh embryo transfer and OC-FET showed risk profiles resembling non-ART for most outcomes. CONCLUSION: Increased perinatal risk associated with ART is not uniform but concentrated primarily in HRC-FET. Perinatal management after HRC-FET should account for bleeding-related complications.