BACKGROUND: Evidence on the effect of maternal complications in pregnancy on wheezing in offspring is still insufficient.

METHODS: A pooled analysis was performed on individual participant data from fourteen European birth cohorts to assess the relationship between several maternal pregnancy complications and wheezing symptoms in the offspring. Exposures of interest included hypertension and preeclampsia, diabetes, as well as pre-pregnancy overweight (body mass index between 25 and 29.9) and obesity (body mass index ≥ 30) compared with normal weight (body mass index between 18.5 and 24.9). Outcomes included both ever and recurrent wheezing from birth up to 12-24 months of age. Cohort-specific crude and adjusted risk ratios (RR) were calculated using log-binomial regression models and then pooled using a random effects model.

RESULTS: The study included 85509 subjects. Cohort-specific prevalence of ever wheezing varied from 20.0% to 47.3%, and of recurrent wheezing from 3.0% to 14.3%. Adjusted pooled RR for ever and recurrent wheezing were: 1.02 (95% CI: 0.98-1.06) and 1.20 (95% CI: 0.98-1.47) for hypertensive disorders; 1.09 (95% CI: 1.01-1.18) and 1.23 (95% CI: 1.07-1.43) for preeclampsia; 1.04 (95% CI: 0.97-1.13) and 1.24 (95% CI: 0.86-1.79) for diabetes; 1.08 (95% CI: 1.05-1.11) and 1.19 (95% CI: 1.12-1.26) for overweight; 1.12 (95% CI: 1.08-1.17) and 1.16 (95% CI: 0.97-1.39) for obesity. No heterogeneity was found in RR estimates among the cohorts, except for diabetes and recurrent wheezing (P=0.027).

CONCLUSIONS: Preeclampsia, maternal pre-pregnancy overweight and obesity are associated with an increase risk of wheezing in the offspring.