Viral infections during pregnancy raise several clinical challenges, including birth
defects in the offspring. Thus, this systematic review and meta-analysis aims to prove
and highlight the risk of birth defects after first-trimester maternal influenza infection.
Our systematic search was performed on 21 November 2022. Studies that reported maternal
influenza infection in the first trimester and non-chromosomal congenital abnormalities
were considered eligible. We used odds ratios (OR) with 95% confidence intervals (CIs)
to measure the effect size. Pooled ORs were calculated with a random effects model.
Heterogeneity was measured with I² and Cochran's Q tests. We found that first-trimester
maternal influenza was associated with increased odds of developing any type of birth
defects (OR: 1.5, CI: 1.30-1.70). Moreover, newborns were more than twice as likely
to be diagnosed with neural tube defects (OR: 2.48, CI: 1.95-3.14) or cleft lip and
palate (OR: 2.48, CI: 1.87-3.28). We also found increased odds of developing congenital
heart defects (OR: 1.63, CI: 1.27-2.09). In conclusion, influenza increases the odds
of non-chromosomal birth defects in the first trimester. The aim of the present study
was to estimate the risk of CAs in the offspring of mothers affected by first-trimester
influenza infection.
