The risk of air pollution exposure during pregnancy


Pregnant women living in areas that are air pollution hotspots are at increased risk of giving birth to children with a cleft lip and palate (CLP).

In a recent study, the South African Medical Research Council (SAMRP) examined cases of patients with CLP from 2006 to 2020. Drawing from two databases, a total of 2 515 cases were studied in relation to air pollution assessed at the mother’s residence. The research identifies an association between the increasing trend in cleft lip births and a mother’s exposure during early pregnancy to particulate matter (PM) air pollution,  particularly PM2.5

“PM2.5 is one of the most harmful pollutants to human health. It is the particle which goes very deep into someone’s lungs and crosses over into the bloodstream,” says Dr Caradee Wright, Chief Specialist Scientist in the Environment and Health Research Unit at the SAMRC, and lead study author. 

The South African National Ambient Air Quality Standards for PM2.5 is 20 micrograms per cubic metre (20µg/m3), which exceeds the World Health Organisation (WHO) air quality guidelines of five micrograms per cubic metre  (5µg/m3). This means that South Africa’s levels are four times higher than the recommended threshold.

“We should be better at managing all of those sources of particulate matter whether it’s diesel exhausts, coal-fired power stations,mining, or domestic fuel burning. Load shedding is also causing everyone to resort to all sorts of alternative energy sources, and this is just going to potentially exacerbate our air pollution problem”, says Wright.  

Air pollution and CLP hotspots

CLP birth hotspot clusters were found in district municipalities in the provinces of Gauteng, Limpopo, North-West, Mpumalanga, and Free State. Wright points out that these hotspots are mostly in informal settlements, lower income and working class communities, where air quality levels are usually worse. This is because residents rely on wood and coal for cooking and for heating, exposing them to particulate matter. 

Other possible causes of a cleft lip and palate include genetics, what the mother eats and drinks, whether a mother smokes, or uses a certain type of medication during pregnancy. 

Air pollution linked to stillbirths

South Africa’s stillbirth rate of 23 per 1000 birth is regarded as unacceptably high by obstetric experts. There’s no national study looking into the relationship between stillbirths and maternal air pollution exposure, but there is global evidence indicating there’s an adverse effect. 

An analysis of PM2.5-related stillbirths in 137 countries revealed that 40% of stillbirths in Africa, Asia and Latin America were caused by exposure to PM2.5

It is still unclear how it causes foetal deaths, but researchers say fine particles may directly cross the placental barrier, hindering oxygen transmission to the foetus, and leading to ‘irreversible embryonic damage’. 

No consequences for not reducing air pollution levels 

“People don’t complain about air pollution because they can’t see it. What they can see is the beautiful winter sunsets in Johannesburg with all the colours reflecting. This is actually the sunlight bouncing off of all the pollution in the air,” says Rico Euripidou, research manager at GroundWork, an environmental research organisation. 

He says nothing is being done to control air pollution and comply with air quality standards, calling the policies of the Department of Environmental Affairs ‘paper tigers, gathering dust on a shelf.’

Albie Modise, Chief Director of Communications from the Department of Forestry, Fisheries And The Environment told Health-e ‘in areas where National Ambient Air Quality Standards are not complied with, provinces and municipalities are not faced with any consequences.’ “They are required to strengthen their interventions and mitigation strategies to reduce air pollution in the case of non-compliance.”

In light of the SAMRC findings, the department said that they will continue to implement measures to reduce pollution to acceptable levels that are protective of human health and wellbeing, as well as the environment.

“Air pollution is not an environmental issue. It is a health issue. We need the Department of Health to come to the table when it comes to addressing the impact of air pollution on people’s health”, says Euripidou.-Health-e News


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