A comparative analysis of fetal mirror-image dextrocardia in China pre- and post-COVID-19 lockdown lifting

To analyze the epidemiological characteristics and incidence of mirror-image dextrocardia in pregnant women and fetuses before and after the lifting of coronavirus disease (COVID-19) control measures in China on December 7, 2022.

We retrospectively collected data on the number of pregnant women who underwent prenatal ultrasound examinations and incidence of mirror-image dextrocardia in fetuses at three hospitals in Xi'an during three time periods: before the COVID-19 pandemic (January to April 2019), during the COVID-19 control measures (January to April 2022), and after the lifting of COVID-19 restrictions (January to April 2023). We then conducted an online epidemiological survey among pregnant women across China and collected the names of pregnant women with fetal mirror dextrocardia, as well as the following clinical information: age, location (province and city), gestational week at which mirror-image dextrocardia was detected, last menstrual period date, date of first pregnancy diagnosis, obstetric history, conception method, estimated due date, ultrasound diagnosis result, and genetic testing result. COVID-19-related information was also recorded.

Between January and April 2019 (pre-pandemic), 9,112 pregnant women underwent prenatal ultrasound examinations at 3 hospitals in Xi'an. Between January and April 2022 (COVID-19 control measures period), 11,071 pregnant women underwent prenatal ultrasound examinations, and 1 case of fetus with mirror-image dextrocardia was identified (incidence rate, 0.9/10,000). Between January and April 2023 (after the lifting of COVID-19 restrictions), 11,516 pregnant women underwent prenatal ultrasound examinations, and 21 fetuses with mirror-image dextrocardia were detected, with an alarming incidence rate of 18.2/10,000. After the lifting of COVID-19 restrictions, the incidence of mirror-image dextrocardia in fetuses in Xi'an showed a significant increase (8-20-fold higher) compared to that observed in both the pre-pandemic and strictly controlled pandemic periods. An online investigation showed that 111 cases of fetal mirror-image dextrocardia were detected in 22 other provinces of China after the lifting of COVID-19 restrictions. All pregnant women with fetal mirror-image dextrocardia had a history of SARS-CoV-2 infection after the lifting of COVID-19 restrictions, which coincided with the early stages of embryo development, approximately 4-6 weeks after their last menstrual period.

Our data showed that the increase in cases of fetal situs solitus with dextrocardia coincided temporally with the outbreak of COVID-19 in China. This temporal overlap may suggest a potential association between the two events.