Researchers discuss whether coffee really affects pregnancy

Researchers from the University of Queensland, Australia have discovered through genetic analysis that coffee consumption may not affect pregnancy after all.

Pregnant women can put their mind at ease with researchers at the University of Queensland (UQ) in Australia finding that enjoying a daily latte or long black while pregnant causes no increased risk to pregnancy.

Dr Gunn-Helen Moen, Dr Daniel Hwang and Caroline Brito Nunes from the Institute for Molecular Bioscience at the UQ used genetics to analyse coffee drinking behaviour.

“Two years ago, we came across an observational study that coupled the adverse effects of coffee and pregnancy together and had concluded that coffee is bad for pregnant women. After closer inspection, we realised this association didn’t separate other risk factors such as smoking, alcohol or poor diet,” says Dr Daniel Hwang.

“We decided to actually investigate whether there was a relationship between coffee consumption and pregnancy risks.”

Dr Gunn-Helen Moen says current World Health Organization guidelines state that pregnant women should drink less than 300 milligrams of caffeine, or two to three cups per day.

“But that’s based on observational studies from women who, let’s say, drink coffee because they don’t sleep well or they’re stressed at their job or have a cigarette with their coffee, that could influence pregnancy outcomes. Maybe having sugar or cream in coffee affects the results too. It doesn’t necessarily reflect that coffee is the thing that causes negative pregnancy outcomes,” says Moen.

“We wanted to find out if coffee alone really does increase the risk of adverse pregnancy outcomes, and the research shows this isn’t the case.”

Hwang says coffee drinking behaviour is partly due to genetics, with a specific set of genetic variants affecting how much coffee we drink.

“We showed that these genetic variants not only affect coffee consumption in the general population but also in pregnant women,” he says.

To qualify their findings, researchers used a method called Mendelian Randomisation, which used eight genetic variants to predict pregnant women’s coffee drinking behaviour and examine whether these variants were also associated with birth outcomes.

“Because we can’t ask women to drink prescribed amounts of coffee during their pregnancy, we used genetic analyses to mimic a randomised control trial,” Hwang says.

Dr Daniel Hwang (left), Dr Gunn-Helen Moen (centre) and Caroline Brito Nunes (right) are researchers at the University of Queensland.

“We first looked at whether these genetic variants were associated with how many cups of coffee women report drinking during week 32 of pregnancy. We then used those genetic variants to see if there was a link between coffee drinking and adverse outcomes to pregnancy,” says Moen.

“We have previously shown that genetic variants for folate levels have a similar effect on birthweight as taking folate supplements, and therefore that using this genetic technique offers the same results as randomised control trials.

“While the Mendelian Randomisation technique has been around for a while, we are one of the first groups of researchers using it for maternal and offspring outcome.”

The genetic analysis found there was no greater risk of miscarriage, stillbirth or premature birth for women who drank coffee.

“When it comes to diet during pregnancy women are often advised to cut things out, but this study shows they can still enjoy coffee without worrying about increasing the risk of these pregnancy outcomes,” Hwang says.

The researchers emphasise the study only looked at certain adverse pregnancy outcomes, and it is possible caffeine consumption could affect other important aspects of foetal development.

“For that reason, we don’t recommend a high intake during pregnancy, but a low or moderate consumption of coffee, within the recommended two or three cups a day. But if women are worried about whether having a cup of coffee will increase their risk of stillbirth and miscarriage, I can say that probably isn’t the case,” Moen says.

This research used genetic data from the Coffee and Caffeine Genetics Consortium, the UK BioBank, the Avon Longitudinal Study of Parents and Children and 23andMe.

This article was first published in the July/August 2022 edition of Global Coffee Report. Read more HERE.

Send this to a friend