Toxic cooking fumes cause life-threatening complications in pregnant women with high blood pressure

Indoor household pollution is more commonly seen in low- and middle-income countries because of cooking and heating with solid fuels, such as wood and charcoal, and has been proven to increase the risk of adverse birth outcomes, including placental hypoxia (when the fetus does not get enough oxygen).

The researchers evaluated more than 2,690 cases of eclampsia in Ethiopia, Haiti, India, Malawi, Sierra Leone, Uganda, Zambia and Zimbabwe, and found a significant correlation between deaths due to indoor household pollution and eclampsia rates -- and the correlation was even more prominent when eclampsia occurred at home.

King's College London's Professor Andrew Shennan, one of the lead authors on the paper published in the International Journal of Gynecology & Obstetrics, said the findings demonstrate how air pollution can impact vulnerable populations the most.

"In-house cooking and household pollution may increase the risk of seizures. We believe that less oxygen will get to the mother's brain, and this may trigger a fit in women who already have pre-eclampsia" he said.

"We are lucky to have such a large dataset of women with eclampsia, as it only occurs in 1% of women with pre-eclampsia. This has allowed us to uncover this new finding.

"This could help explain observed inequalities in maternal healthcare in low- and middle-income countries."

In a previous study by King's College London, scientists found that ninety-four percent of maternal deaths occur in low- and middle-income countries, with 22% due to hypertensive (high blood pressure) disorders like eclampsia.

Professor Shennan added: "Knowing why women have these severe outcomes allows us to reduce the risk of eclampsia and work out how to save lives.

"We have large programmes of work in India, Sierra Leone and Zambia where many women have complications related to high blood pressure. Our current research is aimed at identifying the women at risk but now we are looking at ways to reduce risk, including earlier delivery. This data will help us to give advice about avoiding risk at home."

Researchers will next examine whether climate change increases the prevalence of pre-eclampsia or increases the morbidity from serious manifestations such as eclampsia.