WebMD Medical News
Louise Chang, MD
Jan. 25, 2006 -- Good news for pregnant women who can’t bear the thought of
giving up their daily coffee.
One of the most rigorous studies ever to examine the issue found no link
between moderate caffeine consumption late in pregnancy and either preterm
delivery or low birth weight.
The Danish study compared pregnancy outcomes among women who mainly drank
decaffeinated instant coffee during the second half of their pregnancy and
those who drank at least three cups of caffeinated instant coffee a day.
No significant differences were seen in gestation times or birth weights
among babies born to the two groups.
“I think we can say that moderate caffeine intake does not impact birth
weight or pregnancy length,” lead researcher Bodil Hammer Bech, MD, PhD, tells
However, the study did not address the safety of caffeine consumption during
the early months of pregnancy or the impact of consuming very large amounts of
An earlier study from the same Danish research group suggested a link
between very high coffee consumption and stillbirth.
“It would be reasonable to advise pregnant women to drink no more than three
cups of coffee a day due to the fact that high (caffeine) intake may increase
the risk of fetal death,” Bech says.
The Danish investigation looked at 1,200 healthy pregnant women who reported
drinking at least three cups of caffeinated coffee a day, and who were less
than 20 weeks pregnant when they entered the study.
The women were divided into two groups, with one group drinking mostly
caffeinated instant coffee and the other group drinking instant decaffeinated
The women didn't know what kind of coffee they were given by the
Also, they were not advised to avoid intake of other caffeinated items --
such as tea, chocolate, cola, or other coffee. However, caffeine intake from
these and other food and beverage sources was monitored closely.
The researchers adjusted for other risk factors for poor pregnancy outcome,
including the mother’s age, weight, and smoking status.
The average daily intake of caffeine for women who drank mostly
decaffeinated coffee was 117 milligrams a day -- roughly the amount of caffeine
found in three 12-ounce soft drinks.
Women in the caffeinated-coffee group ended up consuming about 317
milligrams of caffeine a day -- the equivalent of four cups of instant
caffeinated coffee, or two and a half cups of brewed coffee.
The average birth weight of babies born to the women in the lower caffeine
group was 7.75 pounds, compared to 7.8 pounds for babies born to women who
consumed more caffeine.
In the caffeinated group, 4.2% of infants were born prematurely and 4.5%
were small for their gestational age, vs. a premature and underweight birth
rate of 5.2% and 4.7%, respectively, in the decaffeinated group.
None of those differences reached statistical significance, meaning the
differences could have been due to chance.
The Danish group's findings appear in the Jan. 26 issue of BMJ
While the researchers found no evidence that caffeine influences outcomes
late in pregnancy, concerns about its impact early in pregnancy and even before
Drinking five or more cups of coffee a day was found to double a pregnant
woman’s risk of having a miscarriage in a Swedish study reported in 2000. There
have also been suggestions that caffeine can lower fertility.
The March of Dimes, a group that works to prevent birth defects, recommends
that pregnant women drink no more than two 8-ounce cups of coffee a day, and
that they watch their intake of caffeinated tea, colas, and chocolate.
March of Dimes Deputy Medical Director Diane Ashton, MD, MPH, says pregnant
women should limit their caffeine consumption as much as possible.
“If you can avoid caffeine altogether, that is probably ideal,” she tells
“One or two cups of coffee a day probably won’t pose a problem for most
women," Ashton says. "But a woman who has had recurrent pregnancy
losses or who is having problems becoming pregnant might want to consider a
SOURCES: Bech, B. BMJ Online First, Jan. 26, 2007; online edition.
Bodil Hammer Bech, MD, PhD, Institute of Public Health, department of
epidemiology, University of Aarhus, Aarhus, Denmark. Diane Ashton, MD, MPH,
deputy medical director, March of Dimes. The New York Times: “Study
Links Use of Caffeine to Higher Risk of Miscarriage.” WebMD Medical News: “Too
Much Coffee Risky During Pregnancy.” March of Dimes web site.
The Health News section does not provide medical advice, diagnosis or treatment. See additional information.