Moderate Caffeine Consumption During Pregnancy Does Not Increase Miscarriage Risk
Caffeine is a stimulant that crosses the placenta, meaning it easily passes from mother to child. Based largely on data from animal studies showing harmful effects of caffeine on fetuses, the FDA has advised since 1981 that pregnant women "avoid caffeine-containing foods and drugs, if possible, or consume them only sparingly."
But as Brenda Eskinazi, PhD, points out in an editorial accompanying Klebanoff's study, most pregnant women do not heed this advice. "In part because of our own dependence on our morning cup of coffee, and because of our inability to find strong associations with effects on health in humans, we have accepted that more than 75% of pregnant women consume caffeinated beverages," writes Eskinazi, of the University of California School of Public Health, Berkeley. She says health care providers should continue to counsel women who are pregnant or breast-feeding to limit their caffeine intake. Eskinazi also points out that in addition to the risk of miscarriage, caffeine has been linked in animal and human studies to changes in fetal heart rate and breathing patterns, decreased brain weight and alterations in brain development, learning and memory.
"We only looked at risk of spontaneous abortions [miscarriages] in this study and we didn't see any increased risk until women were consuming very large amounts of caffeine," Klebanoff says. "So it seems to me that the best advice is that moderation in all things is always a good idea, but there are probably more important things for pregnant women to worry about than whether they are having a cup of coffee or two a day or a cup of tea or two a day."
- Drinking moderate amounts of caffeine does not appear to increase the risk of miscarriage in pregnant women.
- The rate of miscarriage does start to increase in women who drink more than five cups of coffee per day.
- The majority of women continue to drink caffeine during pregnancy, although they should still be advised to limit consumption.