CHICAGO — Pregnant women can consume moderate amounts of caffeine without increasing their chance of miscarrying or stunting the growth of their fetuses, researchers say.

A study of 431 expectant mothers found those who consumed up to 300 milligrams of caffeine daily — about three cups of coffee, seven cups of tea or eight cans of cola — had no higher rates of miscarriage or small fetuses than nonconsumers of caffeine.

“This is good news for women. They don’t have to be too anxious about consuming reasonable amounts of caffeine during pregnancy,” said Dr. James L. Mills, the lead researcher.

“For higher consumption, we didn’t see any problems, but we didn’t have enough people to assume they aren’t there.”

Mills is chief of pediatric epidemiology at the National Institute of Child Health and Human Development. The study is published in Wednesday’s Journal of the American Medical Association.

The research addresses the last two major questions about the possible harm of caffeine during pregnancy, the authors said.

The first major question — whether caffeine increases rates of birth defects — has been ruled out by recent studies indicating it doesn’t, the authors said.

Early studies that linked caffeine to birth defects, miscarriages and fetal growth retardation had various faults, including failing to account for the effects of smoking, which can harm fetuses, Mills said.

The new study enrolled women at the beginning of their pregnancies — so that caffeine consumption, fetal growth and miscarriage rates could be tracked — and researchers adjusted for the effects of smoking, he said.