As compared to women who avoid caffeine, those who drink two or more cups of coffee have a higher risk of having a miscarriage. Caffeine is known to have various side effects. It is believed that women who are pregnant or are actively trying to become pregnant should stop drinking coffee for three months or hopefully throughout pregnancy. Caffeine is harmful because it stresses the fetus' immature metabolism. It can also decrease blood flow in the placenta, which could harm the fetus. To examine the correlation between caffeine and the risk of miscarriage in pregnant women, researchers in the US studied 1,063 pregnant women who were members of the Kaiser Permanente health plan in San Francisco, for a period of 2 years. The women in this group never changed their caffeine consumption during pregnancy. In the results, it was found that was women who consumed the equivalent of two or more cups of regular coffee or five 12-ounce cans of caffeinated soda - were twice as likely to miscarry as pregnant women who avoided caffeine. This risk appeared to be related to the caffeine, rather than other chemicals in coffee, because they also saw an increased risk when the caffeine was consumed in soda, tea, and hot chocolate. Therefore, it can be said that high doses of caffeine during pregnancy significantly increase the risk of miscarriage. And pregnant women should avoid caffeine consumption as far as possible.
American Journal of Obstetrics and Gynecology ,
January 2008