Drinking one or two cups of coffee a day during pregnancy could increase risk of children growing up overweight or obese, a new study has claimed.

The research, published in the journal BMJ Open, has found that the children of women who drank coffee during pregnancy had a greater chance of becoming overweight during preschool and school ages.

The study does not directly show that caffeine causes an increase in weight, but the researchers at Sahlgrenska Academy in Sweden and the Norwegian Institute of Public Health urged caution when it comes to consuming caffeinated beverages.

The National Food Agency in Sweden has previously recommended drinking not more than 300 milligrams of caffeine or three cups of coffee per day during pregnancy, but the new research suggests that even the recommended doses can pose a risk to pregnant women.

"There may be good cause to increase the restriction of the recommended maximum of three cups of coffee per day. Caffeine is not a medicine that needs to be consumed," said Dr. Verena Sengpiel, associate professor in obstetrics and gynecology at Sahlgrenska Academy, according to Psych Central.

Data for the research was based on the Norwegian Mother and Child Cohort Study (MoBa), which studied 50,943 pregnant women. The children born to the participants of the survey were followed until they were 8 years old.

The study found that the number of five-year-old children who were obese was five percent greater among the group whose mothers had the highest consumption of caffeine compared to the group whose mothers had the lowest consumption.

Researchers also found that the risk of having overweight or obese children was present among women who consumed the recommended maximum amount of caffeine during pregnancy.

"In the Nordic countries, coffee is the primary source, while women in, for example, England receive the greatest amount of caffeine from black tea. If you look at mothers in the younger age group, it comes from energy drinks. We included different sources in the study and found a similar association between caffeine consumption from these different sources and children's growth," Sengpiel said, according to Psych Central.

Sengpiel said that more studies are needed to establish the link between caffeine and obesity and children. In the meantime, the physician suggested that pregnant women either reduce their consumption of caffeine or refrain from it altogether.