Born too late? Climate change may be delaying births

The study analysed data from nearly 400,000 births in Western Australia and found that higher exposure to fine particulate air pollution (PM2.5) and biothermal stress (a measure that combines air temperature, radiant temperature, relative humidity, wind speed, and human physiology) was associated with pregnancies lasting beyond 41 weeks.

Lead author Dr Sylvester Dodzi Nyadanu from Curtin's School of Population Health said while climate exposure has long been linked to preterm births, this is the first study to examine its impact on prolonged pregnancies.

"We know that being 'born too soon' -- preterm birth -- has well-documented health risks, but little attention has been given to the risks associated with being 'born too late'," Dr Nyadanu said.

"Our findings show that exposure to air pollution and biothermal stress during pregnancy increases the likelihood of prolonged pregnancies, particularly among mothers over 35 years old, first-time mothers, those living in urban areas, and those with complicated pregnancies.

"Environmental stressors, including climate-related exposures during pregnancy, have been associated with maternal stress response and subsequent disruptions in endocrine and inflammatory activities, which increase towards the end of pregnancy. This can either shorten gestation, leading to preterm birth, or lengthen gestation, resulting in prolonged pregnancy in some cases."

Dr Nyadanu said prolonged pregnancy can have serious health implications for both mother and baby, including the need for medical interventions such as labour induction or caesarean sections, increased risk of stillbirth, birth complications, child mortality, early childhood behavioural and emotional problems, and emotional impacts on families.

"With climate change driving more frequent extreme weather events and worsening air quality, it is essential that we recognise the potential impacts on maternal and child health," Dr Nyadanu said.

"Healthcare providers, policymakers and pregnant women -- particularly those in vulnerable groups -- must consider climate-related exposures when assessing pregnancy risks and planning interventions.

"This study highlights the need for targeted policies and preventative measures to reduce climate-related health risks, including better air quality regulations and public health initiatives aimed at protecting expectant mothers and children from extreme climatic conditions."