Dr Gunn-Helen Moen and PhD student Shannon D’Urso from UQ’s Institute for Molecular Bioscience (IMB) led an in-depth genetic analysis of data from tens of thousands of families in Norway.

“Scandinavians are some of the biggest coffee consumers in the world, drinking at least 4 cups a day, with little stigma about drinking coffee during pregnancy,” Dr Moen said.

“Our study used genetic data from mothers, fathers and babies as well as questionnaires about the parents’ coffee consumption before and during pregnancy.

“The participants also answered questions about their child’s development until the age of 8, including their social, motor, and language skills.”

“Our analysis found no link between coffee consumption during pregnancy and children’s neurodevelopmental difficulties.”

The researchers said physiological changes during pregnancy prevent caffeine breaking down easily and it can cross the placenta and reach the foetus, where there are no enzymes to metabolise it.

Caffeine accumulation was thought to impact the developing foetal brain, but Dr Moen said previous observational studies couldn’t account for other environmental factors such as alcohol, cigarette smoke or poor diet.

“We used a method called Mendelian randomisation which uses genetic variants that predict coffee drinking behaviour and can separate out the effect of different factors during pregnancy,” she said.

“It mimics a randomised controlled trial without subjecting pregnant mothers and their babies to any ill effects.

“The benefit of this method is the effects of caffeine, alcohol, cigarettes and diet can be separated in the data, so we can look solely at the impact of caffeine on the pregnancy.”

The researchers use genetic analysis to understand complex traits and diseases especially in early life, with a previous study by Dr Moen showing that drinking coffee in pregnancy did not affect birth weight, risk of miscarriage or stillbirth.

They emphasise the importance of following advice from healthcare providers to limit caffeine consumption during pregnancy, as caffeine may influence other pregnancy outcomes.

The researchers are now looking to apply similar analyses to understand more about genetic and environmental causes of neurodiversity, and the effect of it from other factors on brain development during pregnancy.

The research team included international collaborators in Norway including Professor Alexandra Havdahl from PsychGen Center for Genetic Epidemiology and Mental Health, Norwegian Institute of Public Health, Oslo and England as well as IMB’s Caroline Brito Nunes, Dr Daniel Hwang and Professor David Evans. The research was conducted using data from the Norwegian Mother, Father and Child Cohort Study (MoBa).

The research was published in Psychological Medicine.