Observed Prevalence of Congenital Situs Inversus in the United States Before and During the SARS-CoV-2 Pandemic, 2017-2022.

BACKGROUND

Reports from China describe an increase in the frequency of fetal situs inversus in 2023 after the country's "zero-Covid" policy was lifted, suggesting an association with maternal SARS-CoV-2 infection. However, a report of birth defects surveillance data from Scandinavia observed no sustained increase during the SARS-CoV-2 pandemic (2020-2022 vs. 2018-2019). We examined birth defects surveillance data to assess any increase in situs inversus in the U.S. during the SARS-CoV-2 pandemic.

METHODS

We combined data from four population-based birth defects programs in Massachusetts, Minnesota, North Carolina, and Atlanta, Georgia, to compare the prevalence of situs inversus among infants and fetuses delivered before (2017-2019) and during (2021-2022) the SARS-CoV-2 pandemic. We defined situs inversus as mirror-image transposition of the heart and/or other organs, or primary ciliary dyskinesis with situs inversus, excluding isolated dextrocardia. The programs varied in the pregnancy outcomes included (live births ± non-live births); all included both prenatal and postnatal diagnoses.

RESULTS

We identified 294 infants and fetuses with situs inversus (6.8% non-live births). We estimated the combined prevalence per 10,000 live births as 1.72 during the pandemic versus 1.71 before the pandemic (OR = 1.005; 95% CI: 0.778-1.297). The estimated annual prevalence ranged from 1.41 in 2017 to 2.21 in 2019 with no significant trend across the study period (p = 0.39).

CONCLUSIONS

We did not observe an increase in situs inversus during the SARS-CoV-2 pandemic. Because information about SARS-CoV-2 infection among individual pregnancies was not available from all programs, we could not assess a specific association with maternal infection.