Table 4 Impact of indoor air pollution on stillbirth and perinatal mortality

Mavalankar et al. 1991 [29]

India (Ahmedabad). Urban hospital.

Case-control study of stillbirth cases (N = 451), early neonatal death (N = 160), and healthy controls (N = 1465).

Used interviews to assess exposure to cooking smoke during pregnancy and assess odds of stillbirth and early neonatal death based on exposure status.

SB: adjusted OR = 1.5 (95% CI: 1.0–2.1) [NS]

Mishra et al. 2005 [30]

India, population-based data.

Analysed data from the Second National Family Health Survey (1998–99), N = 19189 ever-married women at end of reproductive career.

Used multivariate analysis to assess association of cooking smoke exposure with stillbirth risk, controlling for other factors. Categorised women by response to fuel types used for cooking/heating:

High exposure (wood, dung and crops);

Medium exposure (mix of biomass, cleaner fuels, coal, etc.); and

Low exposure (liquid propane, electricity, kerosene, natural gas).

SB: adjusted OR = 1.44 (95% CI; 1.04–1.97), biomass vs. cleaner fuels.

Recurrent SB: adjusted relative risk (RR) = 2.01 (95% CI: 1.11–3.62), biomass vs. cleaner fuels.

Siddiqui et al. 2005 [31]

Pakistan (Sindh province). Rural, semi-rural, semi-urban setting.

Prospective cohort study of pregnant women (N = 1404) enrolled through a maternal child health surveillance program.

Compared risk of stillbirth among women cooking with biomass (mainly wood) in open fire vs. piped natural gas.

SB: crude OR = 2.28 (95% CI: 1.34–3.90), wood vs. natural gas users.

SB: adjusted OR = 1.90 (95% CI: 1.10–3.20), wood vs. natural gas users