Key result
Extreme heat exposure is linked to increased adverse pregnancy outcomes and PM2.5 to lower gestational weight gain.
Why the study?
Do environmental exposures like PM2.5 and extreme heat influence gestational weight gain, postpartum weight retention, and adverse pregnancy outcomes in pregnant women with overweight or obesity?
Observational (n=303)
Do environmental exposures like PM2.5 and extreme heat influence gestational weight gain, postpartum weight retention, and adverse pregnancy outcomes in pregnant women with overweight or obesity?
Effect estimate: β = -0.19 (PM2.5 on GWG); β = 0.22 (heat on APOs)
p-value: p=0.01 (PM2.5 on GWG); 0.04 (heat on APOs)
Extreme heat exposure during pregnancy increases the risk of adverse pregnancy outcomes, highlighting the need to address environmental stressors in maternal cardiometabolic risk management.
Background: Pregnancy-related complications increase risk for long-term cardiovascular (CV) disease. Environmental exposures such as fine particulate matter (PM 2.5 ) and extreme heat may exacerbate these risks through oxidative stress and inflammation, yet their relationships with perinatal health remain poorly understood. We examined how environmental and psychosocial factors jointly influenced gestational weight gain (GWG), postpartum weight retention (PPWR), and adverse pregnancy outcomes (APOs), including gestational diabetes, preeclampsia, and preterm birth, among a California cohort. Methods: Data were drawn from 303 participants in the GROWell trial, a mobile lifestyle intervention for pregnant and postpartum women with overweight or obesity. Structural equation models (SEMs) tested hypothesized pathways between environmental exposures (latent factors for PM 2.5 and extreme heat over 7-, 30-, and 90-day periods), behavioral and psychosocial variables (diet, physical activity, anxiety), sociodemographics, and maternal outcomes (GWG, PPWR, APOs). Results: Model fit was excellent for both GWG (CFI = 0.88, RMSEA = 0.047) and PPWR (CFI = 0.87, RMSEA = 0.049). Higher PM 2.5 exposure predicted lower GWG (β = –0.19, p = 0.01), while greater physical activity (β = –0.11, p = 0.048) and older age (β = –0.16, p = 0.005) also predicted less gain. Extreme heat was not directly related to GWG but increased odds of APOs (β = 0.22, p = 0.04). In the PPWR model, neither PM 2.5 nor heat predicted weight retention. Anxiety symptoms showed a borderline association with lower PPWR (β = –0.13, p = 0.05). Non-White participants experienced higher PM 2.5 exposure (β = –0.18, p = 0.03), reflecting environmental inequities. Conclusions: Extreme heat increased risk for APOs, whereas higher PM 2.5 exposure was inversely related to GWG. Neither environmental exposure directly predicted PPWR, suggesting complex, time-specific pathways may link environmental stressors to maternal CV risk. Results highlight the need for interventions that address both lifestyle and structural drivers of CV risk across the perinatal continuum. Mobile lifestyle applications could be adapted to provide alerts to users when they are in high heat and high pollution environments to improve maternal outcomes.
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Phipps et al. (2026) conducted an observational in Overweight or obesity in pregnancy (n=303). Climate-related exposures (PM2.5 and extreme heat) vs. Lower exposure levels was evaluated on Gestational weight gain (GWG), postpartum weight retention (PPWR), and adverse pregnancy outcomes (APOs) (β = -0.19 (PM2.5 on GWG); β = 0.22 (heat on APOs), p=0.01 (PM2.5 on GWG); 0.04 (heat on APOs)). Extreme heat exposure increased the odds of adverse pregnancy outcomes (β = 0.22, p=0.04), whereas higher PM2.5 exposure was inversely related to gestational weight gain (β = -0.19, p=0.01).
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