Obesity and asthma during pregnancy: a systematic review and meta-analysis.

Objective: To assess the effect of obesity on the prevalence of asthma, obstetric outcomes and delivery outcomes in pregnant women with asthma.

Methods: A comprehensive systematic review and meta-analysis were conducted up to 31 March 2024, using four public search engines. Following the Preferred Reporting Items for Systematic Reviews and Meta-Analysis guidelines, both quantitative and qualitative data were collected and analysed.

Results: We included 11 studies from 2006 to 2022 involving 77 611 386 pregnant patients (3.1% had asthma). Obesity increased the odds of asthma (n=2; OR 2.42, 95% CI 1.14-5.15) and increased that of uncontrolled asthma (n=6; OR 1.29, 95% CI 1.11-1.50) in pregnant women. In an adjusted pooled analysis, pregnant women with asthma were more likely to develop hypertensive disorders of pregnancy (HDP) (n=3; adjusted OR (aOR) 1.21, 95% CI 1.10-1.34), gestational diabetes mellitus (GDM) (n=3; aOR 1.14, 95% CI 1.04-1.26), fetal growth restriction (FGR) (n=2; aOR 1.18, 95% CI 1.15-1.21), preterm birth (PTB) (n=2; aOR 1.26, 95% CI 1.25-1.27), caesarean delivery (CD) (n=3; aOR 1.22, 95% CI 1.11-1.33) and severe maternal morbidity (n=1; aOR 1.50, 95% CI 1.45-1.55). Three comparator studies that examined the effect of obesity on obstetric outcomes cited obesity as a risk factor for HDP (n=1; aOR 1.7, 95% CI 1.3-2.3), GDM (n=1; aOR 4.2, 95% CI 2.8-6.3) and CD (n=1; aOR 1.6, 95% CI 1.3-2.0) in pregnant women with asthma.

Conclusions: Pregnancy with asthma may increase the risk of HDP, GDM, FGR, PTB and CD, and obesity has the potential to further increase the risk of HDP, GDM and CD in pregnant women with asthma.