Association of secondhand smoke and depressive symptoms in nonsmoking pregnant Women: A systematic review and meta-analysis

Background: Globally about 30% of adult women and 40% of children are exposed to secondhand smoke (SHS) from active smokers. SHS exposure of pregnant women has been associated with postpartum depression. Unexposed women in pregnancy had lower rates of postpartum depression than women exposed to SHS. This systematic review aimed to determine the association of depressive symptoms and exposure to SHS in nonsmoking pregnant women. Method: The case-controlled, cross-sectional, and cohort studies with a comparison group were included. Studies including women who had smoking history during pregnancy were excluded. The comprehensive electronic databases, CINAHL, EMBASE, and Medline were searched. Result: Of the 2777 records screened, seven studies were included in the review for data extraction. The bias of studies was assessed using the RoBANS. We synthesized two studies that showed depressive symptoms at any time during pregnancy and postpartum significantly increased (ORs = 1.77 [95% CI = 1.12 - 2.79]; p = 0.01; I-2 = 28%, 4103 women, two studies), and significantly increased the odds of antenatal suicidal ideation in SHS exposed women (ORs = 1.75 [95% CI = 1.14 - 2.70]; p = 0.01; I-2 = 51%, 2670 women, two studies). Lack of studies from counties with the highest smoking rates was a limitation. Conclusions: SHS exposure during pregnancy showed a significant increase in the odds of depressive symptoms. Furthermore, research is required to clarify to association between SHS and depression.