To explore the effect of natural cycle freeze-thaw embryo transfer on pregnancy outcome in assisted reproductive technology.

A total of 199 cases of patients with singleton live birth delivery who underwent in vitro fertilization and freeze-thaw embryo transfer at Bozhou People's Hospital from March 2020 to March 2021 were selected as the research subjects. The mean age of the patients was (30.7±3.4) years (range, 20-41 years). According to the endometrial preparation plan, the patients were divided into either a natural cycle group (93 cases) or a hormone replacement cycle group (106 cases). The natural cycle group used natural cycle freeze-thaw embryo transfer, and the hormone replacement cycle group used hormone replacement cycle freeze-thaw embryo transfer. The clinical data, neonatal outcome, and perinatal outcome were compared between the two groups.

The age, infertility years, basal follicular estrogen, basal luteinizing hormone, anti-Muller test tube hormone, number of eggs obtained, total gonadotropin in the super-stimulation cycle, normal fertilization number of eggs, and number of embryos transferred in the two groups were comparable with no significant difference (P＞0.05 for all). The rate of infants with normal body weight was significantly higher in the natural cycle group (88.17%) than in the hormone replacement cycle group (66.98%; P=0.017). There was no significant differences in birth weight of macrosomia, low body mass infants, preterm infants, or body weight of neonates between the two groups (P＞0.05 for all). And there was no significant differences in the rates of gestational diabetes mellitus, gestational hypertension, hyperamniotic fluid, hypoamniotic fluid, placental adhesion, placental previa, premature rupture of membranes, or postpartum hemorrhage between the natural cycle group and the hormone replacement cycle group (11.83% vs 16.98%, 7.53% vs 9.43%, 3.23% vs 6.60%, 2.15% vs 6.60%, 3.23% vs 4.72%, 9.43% vs 14.15%, 12.90% vs 16.04%, and 21.51% vs 24.53%, respectively, P＞0.05 for all).

The natural cycle freeze-thaw embryo transfer has a good outcome for pregnancy under assisted reproductive hormones.