Household air pollution and stillbirths in India: analysis of the DLHS-II National Survey.

BACKGROUND

Several studies have linked biomass cooking fuel with adverse pregnancy outcomes such as preterm births, low birth weight and post-neonatal infant mortality, but very few have studied the associations with cooking fuel independent of other factors associated with stillbirths.

METHOD

We analyzed the data from 188,917 ever-married women aged 15-49 included in India's 2003-2004 District Level Household Survey-II to investigate the association between household use of cooking fuels (liquid petroleum gas/electricity, kerosene, biomass) and risk of stillbirth. Prevalence ratios (PRs) were obtained using Poisson regression with robust standard errors after controlling for several potentially confounding factors (socio-demographic and maternal health characteristics).

RESULTS

Risk factors significantly associated with occurrence of stillbirth in the Poisson regression with robust standard errors model were: literacy status of the mother and father, lighting fuel and cooking fuel used, gravida status, history of previous abortion, whether the woman had an antenatal check up, age at last pregnancy >35 years, labor complications, bleeding complications, fetal and other complications, prematurity and home delivery. After controlling the effect of these factors, women who cook with firewood (PR 1.24; 95% CI: 1.08-1.41, p=0.003) or kerosene (PR 1.36; 95% CI: 1.10-1.67, p=0.004) were more likely to have experienced a stillbirth than those who cook with LPG/electricity. Kerosene lamp use was also associated with stillbirths compared to electric lighting (PR 1.15; 95% CI: 1.06-1.25, p=0.001). The population attributable risk of firewood as cooking fuel for stillbirths in India was 11% and 1% for kerosene cooking.

CONCLUSION

Biomass and kerosene cooking fuels are associated with stillbirth occurrence in this population sample. Assuming these associations are causal, about 12% of stillbirths in India could be prevented by providing access to cleaner cooking fuel.