Association between situs inversus and maternal SARS-CoV-2 infection at gestational age 4-6 weeks.

Background: A dramatic increase in fetal situs inversus diagnoses by ultrasound in the months following the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) surge of December 2022 in China led us to investigate whether maternal SARS-CoV-2 exposure could be associated with elevated risk of fetal situs inversus.

Methods: In this multi-institutional, hospital-based, matched case-control study, we investigated pregnant women who underwent ultrasonographic fetal biometric assessment at gestational weeks 20-24 at our hospitals. Each pregnant woman carrying a situs inversus fetus was randomly matched with four controls based on the date of confinement. Relevant information, including SARS-CoV-2 infection, and other potential risk factors were collected. Conditional logistic regression was used to test possible associations between fetal situs inversus and SARS-CoV-2 infection at different gestational weeks as well as individual risk factors.

Findings: A total of 52 pregnant women diagnosed with fetal situs inversus between January 1 and October 31, 2023 and 208 matched controls with normal fetuses were enrolled. We found no association between an increased risk of fetal situs inversus with gestational SARS-CoV-2 infection or with other risk factors. However, fetal situs inversus was significantly associated with SARS-CoV-2 infection specifically in gestational weeks 4-6 (adjusted odds ratio [aOR] 6.54 [95% confidence interval 1.76-24.34]), but not with infection at other gestational ages, after adjusting for covariates.

Conclusions: Increased risk of fetal situs inversus is significantly associated with maternal SARS-CoV-2 infection at gestational weeks 4-6, corresponding to the fetal developmental window for visceral lateralization in humans.

Funding: National Key R&D Program of China, etc.