I am excited to write a letter to share our findings.Coronavirus disease (COVID-19) is an acute respiratory infectious disease caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), which belongs to the family of severe acute respiratory syndrome coronaviruses [1]. On December 7, 2022, the Chinese government lifted the restrictions on controlling the COVID-19 pandemic, which resulted in an explosive increase in the SARS-CoV-2 infection rate among the Chinese population. The self-reported infection rate, as determined from an online survey, reached its peak (15.5%) between December 19 and 21, 2022, with an estimated 82.4% of individuals in China being infected as of February 7, 2023 [2]. Mirror-image dextrocardia is rare, with varying incidence among studies and countries. According to the literature, the incidence ranges from 1/8,000 to 2,0000[3]. In our recent routine prenatal screening of fetuses, we found 4 cases of fetal mirror dextrocardia within just one month. And The last menstrual period of these pregnant women was in November 2022. Is there an association between COVID-19 infection and fetuses with mirror-image dextrocardia? Therefore, we conducted an epidemiological investigation to analyze the 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.
We find that between January and April 2019 (pre-pandemic), 9,112 pregnant women underwent prenatal ultrasound examinations at 3 hospitals in Xi'an, and 2 fetuses with mirror-image dextrocardia were detected (incidence rate 2.2/10,000). Between January and April 2022 (COVID-19 control measures period), 11,071 pregnant women underwent prenatal ultrasound examinations, and 1 case of fetuses with mirror-image dextrocardia were 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 of mirror-image dextrocardia were detected, with an alarming incidence rate of 18.2/10,000(Table 1). 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. And our investigation found that the 111 pregnant women were infected with SARS-CoV-2 approximately 5 weeks after their last menstrual period(Figure 1).The key time for embryonic heart development is 4-8 weeks after conception. This highly suggests that COVID-19 infection is closely related to the formation of fetal mirror dextrocardia in early pregnancy. Due to our limited work, we believe that this discovery is only the tip of the iceberg and it is necessary to conduct large-scale epidemiological investigations and in-depth research on the pathogenesis.