High doses of daily caffeine during pregnancy - whether from coffee, tea, caffeinated soda or hot chocolate - cause an increased risk of miscarriage, according a new study by the Kaiser Permanente Division of Research. Writing in the current online issue of American Journal of Obstetrics and Gynecology, the researchers note that while previous research showed a link between caffeine consumption and miscarriage, this is the first study to thoroughly control for morning sickness, which typically causes many women to avoid caffeine.
Lead researcher De-Kun Li, MD, Ph.D., said that women who consumed 200 mg or more of caffeine per day (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. 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.
The reasons that caffeine can harm a fetus have been suspected for some time. Caffeine crosses through the placenta to the fetus, but 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.
So what's a fatigued mom-to-be supposed to do for her daily energy jolt? "If you definitely need caffeine to get you going, try keeping it to one cup or less a day. Avoiding it may be even better. Consider switching to decaffeinated coffee and other decaffeinated beverages during your pregnancy," said Tracy Flanagan, MD, Director of Women's Health, Kaiser Permanente Northern California. "Learn to perk up instead with natural energy boosts like a brisk walk, yoga stretches, [or] snacking on dried fruits and nuts."
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Source: Kaiser Permanente Division of Research
