Risk of preterm birth in maternal influenza or SARS-CoV-2 infection: a systematic review and meta-analysis.

BACKGROUND

Influenza is a major threat to global health and is an important cause of respiratory diseases. However, there was a controversy on the impacts of influenza infection on adverse pregnancy outcomes and the infant's health. This meta-analysis aimed to investigate the impact of maternal influenza infection on preterm birth.

METHODS

Five databases, including PubMed, Embase, Cochrane Library, Web of Science, and China National Knowledge Infrastructure (CNKI) were searched for eligible studies on December 29, 2022. The Newcastle-Ottawa Scale (NOS) was used to assess the included quality of the included studies. As for the incidence of preterm birth, odds ratios (OR) and 95% confidence intervals (CIs) were pooled, and the results of the current meta-analysis were displayed in forest plots. Subgroup analyses based on similarity in different aspects were conducted for further analysis. A funnel plot was used to assess the publication bias. All of the above data analyses were performed using STATA SE 16.0 software.

RESULTS

A total of 24 studies involving 24,760,890 patients were included in this meta-analysis. Through the analysis, we found that maternal influenza infection significantly increased the risk of preterm birth (OR =1.52, 95% CI: 1.18 to 1.97, I=97.35%, P=0.00). After subgroup analysis based on different types of influenzas, we found that women infected with influenza A and B (OR =2.05, 95% CI: 1.26 to 3.32, I=96.14%, P<0.1), and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) (OR =2.16, 95% CI: 1.75 to 2.66, I=0.00%, P<0.1) in pregnancy were at an increased risk of preterm birth, while those infected with influenza A alone or seasonal influenza were not (P>0.1).

CONCLUSIONS

Women should take active steps to avoid influenza infection during pregnancy, especially influenza A and B and SARS-CoV-2, to reduce the possibility of preterm birth.