A bit of coffee is okay during pregnancy

"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," Daniel Hwang says. (Credit: Getty Images)

Enjoying a bit of coffee causes no increased risk to pregnancy, researchers report.

The researchers used genetics to analyze coffee drinking behavior, and their findings show limited coffee consumption during pregnancy didn’t increase the risk of miscarriage, stillbirth, or premature birth.

“Current World Health Organization guidelines say pregnant women should drink less than 300mg of caffeine, or two to three cups per day,” says Gunn-Helen Moen of the Institute for Molecular Bioscience at the University of Queensland. “But that’s based on observational studies where it’s difficult to separate coffee drinking from other risk factors like smoking, alcohol, or poor diet.

“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.”

Coffee drinking behavior is partly due to genetics, with a specific set of genetic variants affecting how much coffee we drink, says Daniel Hwang of the Institute for Molecular Bioscience.

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

For the study in the International Journal of Epidemiology, the researchers used a method called Mendelian randomization which uses eight genetic variants that predict pregnant women’s coffee drinking behavior and examined 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 randomized control trial,” Hwang says.

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

“For that reason, we don’t recommend a high intake during pregnancy, but a low or moderate consumption of coffee,” Moen says.

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

Source: University of Queensland