The Effect of Household Air Pollution Exposure on Gestational Blood Pressure

Among pregnant patients with elevated gestational blood pressure (BP), use of an intervention with a liquefied petroleum gas (LPG) stove does not markedly affect their condition. These findings were published in the journal Hypertension.

The Household Air Pollution Intervention Network (HAPIN) randomized controlled trial (ClinicalTrials.gov Identifier: NCT02944682) was conducted among pregnant women residing in 4 international research centers in Guatemala, India, Peru, or Rwanda. Researchers performed an intention-to-treat, exposure-response analysis to establish whether exposure to household air pollution is associated with increased rates of gestational diabetes. In the study, they measured BP and personal exposure to particulate matter (PM_2.5), black carbon, and carbon monoxide 3 times during gestation.

Approximately 800 biomass-using households with pregnant women at each international research center were enrolled, with half of the households randomly assigned to receive the intervention that included an LPG stove, a free supply of fuel, and behavioral messaging to encourage exclusive LPG utilization. Those in the control households received no intervention, but they were eligible to receive the same stove and fuel, or an alternative compensation, upon study completion. Gestational BP was evaluated at enrollment (baseline, <20 weeks’ gestation), and at 2 follow-up visits at 24 to 28 weeks’ gestation (follow-up 1), as well as at 32 to 36 weeks’ gestation (follow-up 2).

A total of 3195 pregnant women were recruited for the study. Results of the study show that median 24-hour PM_2.5 declines from 84 μg/m³ to 24 μg/m³ following use of the intervention. Levels of carbon monoxide and black carbon decreases in a similar fashion.

Intention-to-treat analysis found an increase in systolic BP (SBP) and diastolic BP (DBP)  observed in both groups during gestation. However, the increase is significantly higher in the intervention arm both for SBP (0.69 mm Hg; 95% CI, 0.03-1.35; P =.04) and for DBP (0.62 mm Hg; 95% CI, 0.05-1.19; P =.03).

According to findings from the exposure-response analyses, higher exposures to household air pollution are associated with moderately higher SBP and DBP, although none of these associations reach statistical significance.

Limitations of the study include that the investigators are unable to include data on certain confounders, such as salt consumption, which is known to be linked to high BP. There is also the possibility that altered lifestyle and behavioral factors introduced by the LPG stove and fuel may have affected the women’s BP, including changes in physical activity from not needing to collect fuel and change in diet.

“Further studies might explore these associations in cohorts of less healthy women with higher risk of gestational BP increases,” the study authors wrote.

Reference

Ye W, Steenland K, Quinn A, et al; HAPIN trial Investigators. Effects of a liquefied petroleum gas stove intervention on gestational blood pressure: intention-to-treat and exposure-response findings from the HAPIN trial. Hypertension. Published on June 16, 2022. doi:10.1161/HYPERTENSIONAHA.122.19362

This article originally appeared on The Cardiology Advisor