Adverse pregnancy outcomes and lung function later in life: The CARDIA lung study

Pregnancy events are linked to future maternal health, although relationships between adverse pregnancy outcomes (APOs) and maternal respiratory health are unknown.

This is a secondary analysis of CARDIA, a multicenter cohort study. We included all women who had delivered a live infant. APOs were defined as a history of ever having a small-for-gestational-age infant, preterm birth, gestational diabetes mellitus, or hypertensive disorder of pregnancy. Women were categorized as having no, one or >1 pregnancy with any APOs. Outcomes included year 30 lung function, annual change in lung function from year 20-30 and presence of radiographic emphysema at year 25. Adjusted linear regression was used to evaluate associations between APO category and percent predicted forced expiratory volume in 1 s (FEV₁) (ppFEV₁), forced vital capacity (FVC) (ppFVC) and annual rate of decline in FEV₁ and FVC from year 20-30.

Among 657 women, those with >1 pregnancy with APOs had a significantly lower year 30 ppFEV₁ and greater annual decline in FEV₁, compared to those without APOs (β co-efficient -2.45 %; 95 % CI, -4.87 to -0.03, and -6.67 ml/year; 95 % CI, -12.90 to -0.44, respectively). However, after adjustment for parity, findings were no longer statistically significant, raising the question of whether multiparity or recurrent pregnancies with APOs may be driving associations with lower FEV₁.

A history of APOs may represent a novel, early indicator of worse lifetime maternal respiratory health, although larger studies accounting for multiparity and other important confounders are needed to confirm this finding.