Previous studies have shown that 300 mg. of caffeine a day can increase risk of miscarriage. A new study shows this to be true even at 200 mg. per day.

It was previously considered safe to have caffeine equal to the amount of 1-2 cups of coffee per day while pregnant. A new study, published in the Journal of Obstetrics and Gynecology January 2008 issue, indicates that more than 200 milligrams of caffeine per day can increase the risk of miscarriage substantially.

According to the study, women consuming more than 200 milligrams of caffeine per day had a 25.5% chance of miscarriage. For women that did not consume any caffeine, the risk of miscarriage was 12.5%. Even those women that consumed less than 200 mg. of caffeine showed a slight increase in miscarriage. One cup of coffee has an average of 137 mg. of caffeine.

Previous studies (National Institute of Child Health and Human Development) have shown that consuming less than 300 mg. of caffeine did not affect the rates of miscarriage; however, higher rates did. Another study, according to the March of Dimes, suggested that women drinking four or more cups of coffee per day had a greater chance of having a stillborn baby. The more coffee consumed, the greater the risk.

CNN reports that Dr. Li, the lead researcher of the study, indicates that caffeine may be dangerous because the fetus may not be able to metabolize it, it may influence cell development and may decrease blood flow to the placenta. This restricted blood flow may result in miscarriage.

Some common foods with caffeine:

Coffee

137 mg.

Tea

48 mg.

Caffeinated Soft Drinks

37 mg.

Hot Chocolate

12 mg.

Dark Chocolate

30 mg. in 1.45 oz. bar

Semi-sweet Chocolate Chips

26-28 mg. in 1/4 cup

Milk Chocolate

11 mg. in 155 oz. bar

Some pain relievers, such as migraine medicine or cold medicine include caffeine as well. Check all labels and discuss with your doctor before taking any medication when pregnant.

Additionally, some herbal products, for example guarana, may have caffeine. Since herbal products are not regulated by the FDA (Food and Drug Administration, U.S. Government), they are not required to label products with the amount of caffeine they contain. The March of Dimes recommends that pregnant women avoid all use of herbal products.

Additional Information:

Can Aspirin Prevent Miscarriage

References:

Caffeine in Pregnancy, March of Dimes

Caffeine May Boost Miscarriage Risk, Danielle Dellorto CNN, January 21 2008

Caffeine Raises Risk of Miscarriage, Catherine Paddocki, Medical News Today January 21, 2008

Moderate Caffeine Use Does Not Increase Miscarriage But High Use Doubles Risk, National Institute of Child Health and Human Development, 1999