Effect of SARS-CoV-2 infection on pregnant outcomes after embryo transfer: a multicenter retrospective study

With the nationwide relaxation of controls for the COVID-19 epidemic from December 2022 in China, fertility and in vitro fertilization (IVF) centers reported increasing numbers of infected patients in a short time. However, there is a lack of information regarding the effects of SARS-CoV-2 infection on pregnancy outcomes after IVF–embryo transfer (ET)/intracytoplasmic sperm injection (ICSI)–ET/frozen–thawed embryo transfer (FET), especially the live birth rate. This multicenter retrospective study was conducted at three public IVF centers in Jiangsu province of China. Women aged 20–42 years who were undergoing IVF–ET/ICSI–ET/FET treatment were consecutively registered from November 23, 2022 to January 7, 2023, with follow-up until October, 2023. Patients during the same period in the previous year were included in the control group. Each woman contributed only one transplantation cycle. Multivariate regression analysis was used to evaluate clinical outcomes primarily between different policy period other than individual infected or not. Covariates included demographic characteristics (age, body mass index (BMI), infertility cause, anti-müllerian hormone (AMH), and Antral Follicle Counting(AFC)) as well as cycle characteristics (treatment protocol, endometrial thickness, number of embryos transferred, and embryonic morphology). In this study, we included 779 women in the FET group and 168 women in the IVF–ET/ICSI–ET group, analyze the clinical outcomes of each group separately before and after the relaxation of controls for the COVID-19 epidemic. Pregnancy outcomes, including the clinical pregnancy rate, miscarriage rate, ongoing pregnancy rate, multiple pregnancy rate, and live birth rate, did not change significantly in different policy period. However, the rate of gestational diabetes mellitus (GDM) in FET cycles rather than IVF–ET/ICSI–ET cycles after the relaxation of controls was higher than that 1 year earlier (17.8% vs. 6.8%). The findings of this study suggest that the relaxation of controls for the COVID-19 epidemic does not have a clear negative effect on the pregnancy outcomes after ET, despite current clinical concerns. Nevertheless, the morbidity of gestational diabetes in FET cycles after the relaxation of controls warrants greater attention.