Characteristics of the included studies.

Background
Previous studies have yielded conflicting results regarding the link between maternal perinatal depression and asthma in children. To provide a clearer understanding of this relationship, a comprehensive meta-analysis was carried out to evaluate the association mentioned above.
Methods
A comprehensive review of observational studies was conducted by searching electronic databases including Medline, Embase, and Web of Science. The data were combined using a randomized-effects model taking into account potential variations. Subgroup analyses were performed to evaluate the possible impact of study characteristics on outcomes.
Results
Ten cohort studies, which included 833,230 mother-child pairs, were examined in the analysis. Maternal depressive symptoms during the perinatal period were associated with an increased risk of asthma in offspring (risk ratio [RR]: 1.24, 95% confidence interval [CI]: 1.19 to 1.30, p < 0.001; I2 = 0%). Further sensitivity analyses restricted to multivariate studies (RR: 1.24, 95% CI: 1.19 to 1.30, p < 0.001; I2 = 0%) or studies where asthma was diagnosed in children aged three years or older (RR: 1.24, 95% CI: 1.19 to 1.30, p < 0.001; I2 = 0%) revealed consistent outcomes. Subgroup analyses according to study design, methods for the diagnosis of maternal depression, timing for the evaluation of maternal depression, methods for the validation of asthma in offspring, adjustment of maternal smoking during pregnancy and of maternal asthma, or study quality score showed similar results (p for subgroup difference all > 0.05).
Conclusions
Maternal perinatal depression appears to be significantly linked to a higher occurrence of childhood asthma in children.