Prenatal air pollution raises babies’ breathing risks

Pregnant women exposed to indoor air pollution and tobacco smoke may be putting their babies at greater risk of poor growth and breathing difficulties at birth. This is according to research done by paediatricians at the University of Cape Town (UCT).

Published in BMJ Open Respiratory Research, the study analysed data from 1 143 live births in the Drakenstein Child Health Study, one of Africa’s largest birth cohorts, to investigate how indoor air pollution and environmental tobacco smoke affect newborn health.

Researchers found that 17% of babies were born prematurely, 15% had a low birth weight and 7% experienced respiratory distress at birth.

The study showed that babies exposed to high levels of particulate matter (PM₁₀) during pregnancy were nearly twice as likely to experience respiratory distress, while exposure to elevated carbon monoxide levels trended towards a more than double the odds of breathing problems at birth.

“Our findings show that the air a mother breathes can have important consequences for her baby’s health from the moment they are born.”

Researchers also found that active maternal smoking was associated with reduced weight-for-age scores in newborn babies. The findings come from a peri-urban South African setting where household air pollution remains common despite widespread access to electricity. Almost half of all households recorded particulate matter and benzene (volatile organic compound) levels above acceptable ambient standards.

Titled “Antenatal environmental exposure to indoor air pollution and environmental tobacco smoke: Association with birth outcomes in an African birth cohort”, the study also revealed widespread tobacco smoke exposure during pregnancy. Nearly one-third (32%) of mothers were active smokers, while a further 45% were classified as passive smokers using urine cotinine testing.

Importance of reducing environmental exposures

Lead researcher, Professor Aneesa Vanker from UCT’s Department of Paediatrics and Child Health, said the findings reinforce the importance of reducing environmental exposures during pregnancy.

“Pregnancy is a critical window of development, and our findings show that the air a mother breathes can have important consequences for her baby’s health from the moment they are born,” she said.

According to Professor Vanker, air pollution during pregnancy is particularly concerning because pollutants can cross the placenta and potentially affect foetal development before birth.

Vanker and her colleagues, Dr Kirsty Brittain, Dr Whitney Barnett and Professor Heather Zar, measured multiple household pollutants directly inside participants’ homes, including particulate matter, carbon monoxide, nitrogen dioxide, sulphur dioxide and volatile organic compounds, rather than relying solely on self-reported exposure.

“Our findings support policies aimed at expanding access to clean energy and strengthening education campaigns about the dangers of smoking.”

The findings, said Vanker, underscore the need for stronger public health interventions. “Our research shows that reducing indoor air pollution and tobacco smoke exposure during pregnancy could improve birth outcomes and potentially protect children’s respiratory health over the long term,” she said.

The study also highlights persistent inequalities in environmental exposures. Although 93% of households had access to electricity, many families continued to rely on fossil fuels for cooking and heating.

“Our findings support policies aimed at expanding access to clean energy and strengthening education campaigns about the dangers of smoking and household air pollution during pregnancy,” said Vanker, adding that they also call for greater investment in antenatal interventions that help expectant mothers reduce exposure to harmful pollutants.

“Preventing these exposures before and during pregnancy offers an opportunity to improve health outcomes at the very beginning of life with life-long consequences,” Vanker concluded.