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

Abstract

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.