Daily coffee consumption during pregnancy –- whether from coffee, tea, caffeinated soda or hot chocolate — increases the risk of miscarriage, according a new study by the Kaiser Permanente Division of Research.

The study, which published online in the American Journal of Obstetrics and Gynecology, found that consuming 200 mg of caffeine, equal to two cups of coffee per day, doubles a woman's risk of miscarriage during pregnancy.

“This study strengthens the association between caffeine and miscarriage risk because it removes speculation that the association was due to reduced caffeine intake by healthy pregnant women,” said lead investigator, Dr. De-Kun Li of the Kaiser Permanente Division of Research, in a news release.

The study looked at 1,063 pregnant Kaiser Permanente members in San Francisco from October 1996 through October 1998, and examined the caffeine effect among women who never changed their pattern of caffeine consumption during their pregnancy.

Women who consumed two or more cups of regular coffee or five 12-ounce cans of caffeinated soda had twice the miscarriage risk as women who consumed no caffeine, said Li. Women who consumed less than 200 mg of caffeine daily had more than 40 percent increased risk of miscarriage.

The increased risk of miscarriage appeared to be due to the caffeine itself, rather than other possible chemicals in coffee because caffeine intake from non-coffee sources such as caffeinated soda, tea and hot chocolate showed a similar increased risk of miscarriage.

“The main message for pregnant women from these findings is that they probably should consider stopping caffeine consumption during pregnancy because this research provides clearer and stronger evidence that high doses of caffeine intake during pregnancy can increase the risk of miscarriage,” said Li.

Researchers have long suspected caffeine may harm a fetus. Caffeine crosses through the placenta to the fetus and can be difficult for the fetus to metabolize because of the under-developed metabolic system. Caffeine also may influence cell development and decrease placental blood flow, which may lead to an adverse effect on fetal development, the study offered as background.

Overall, 172 of women in the study (16.18 percent) miscarried. Two-hundred-sixty-four women (25 percent) reported no consumption of any caffeine containing beverages during pregnancy, 635 women (60 percent) reported 0-200 mg of caffeine intake per day, and 164 women (15 percent) had 200 mg or more of daily caffeine consumption.

So what’s a fatigued mom-to-be supposed to do for her daily energy jolt?

Dr. Tracy Flanagan, director of Women's Health, Kaiser Permanente Northern California, recommended women limit themselves to one or less cups of coffee per day during pregnancy. “Learn to perk up instead with natural energy boosts like a brisk walk, yoga stretches, snacking on dried fruits and nuts,” she said in a news release.