Consuming caffeine during pregnancy may increase the risk for obesity in childhood, researchers report.

A Norwegian study, in BMJ Open, involved 50,943 mother-infant pairs. The mothers reported their caffeine intake at 22 weeks of pregnancy, and the researchers followed their children over the next eight years.

After adjusting for other variables, the scientists found that compared with the children of women who consumed less than 50 milligrams of caffeine a day, those whose mothers had 50 to 199 milligrams were only slightly more likely to be overweight at ages 3 through 8 years. (A cup of brewed coffee contains about 100 to 150 milligrams of caffeine.)

But those whose mothers had 200 to 299 milligrams a day were 12 to 17 percent more likely to be overweight through age 5, and those whose mothers consumed more than 300 milligrams a day — two to three cups — were 29 to 44 percent more likely to be overweight or obese through age 8.

The study is observational and draws no conclusions about causality, but the senior author, Dr. Verena Sengpiel, of the Sahlgrenska University Hospital in Gothenburg, Sweden, said that “Women should stick to the current recommendations, and then try to reduce as much as possible. Caffeine isn’t a substance you need.”

The American College of Obstetrics and Gynecology recommends no more than 200 milligrams of caffeine a day during pregnancy.