Caffeine 77tation shows that caffeine reduces female fertility, produces smaller than usual
offspring, and may affect brain development.
Research in Yugoslavia indicates that pregnant women who do not smoke
cigarettes but do take more than 71 mg of caffeine daily have smaller infants.
A British study found the opposite; slightly smaller infants came from
cigarette-smoking women who used 1,000 mg or more of caffeine a week, but
the effect was not seen in nonsmokers. Still other studies find no connection
between caffeine and either birthweight or prematurity.
Caffeine affects vital signs in a human fetus even when the dose is so low
as to have no influence on the pregnant woman.
Question has arisen about whether caffeine promotes spontaneous abortion;
a study published in 1994 found 140 mg to 280 mg a day to pose a significant
risk; a rigorous study published in 1999 was unable to find such a hazard
among moderate caffeine users; and a study published in 1993 saw caffeine
as reducing the incidence of spontaneous abortion. Still another study found
that women who drank decaffeinated coffee were even more likely to expe-
rience a spontaneous abortion than women who drank caffeinated coffee. Re-
search in New Zealand indicated that sudden infant death syndrome (SIDS)
was more likely if a woman had ingested more than 400 mg of caffeine daily
during pregnancy, but an examination of SIDS in Scandinavia found no cor-
relation with caffeine use during or after pregnancy.
Instant coffee can damage DNA, but implications for general health or birth
defects are unclear. Testing caffeine on mice produced birth defects in limbs,
and tests on chicken embryos produced heart deformities. Chicken embryos,
however, are so sensitive to various chemicals that such results are not con-
sidered a warning of human danger. Indeed, a substantial body of research
indicates that caffeine causes no human birth defects.
Evidence does exist that caffeine can increase the likelihood of birth defects
caused byalcoholand tobacco. An Egyptian study found that caffeine in-
creases alcohol birth defects in rats.
A statistical study showed that women who use more than 300 mg of caf-
feine daily around the time of conception and who do not smoke are less
likely to have infants with Down syndrome.
Given all the uncertainties, pregnant women are advised to use caffeine
“moderately”—no more than 200 mg to 300 mg daily (150 mg or less is con-
sidered “minimal”).
Caffeine increases milk production in nursing mothers and passes into the
milk but appears unharmful to infants if the women are moderate users. On
occasions when mothers use a lot of caffeine, however, their nursing infants
may be fussier and have more trouble sleeping. A dose lasts longer in infants
than in older persons.
Additional scientific information may be found in:
Anderson, M.E., et al. “Improved 2000-Meter Rowing Performance in Competitive
Oarswomen after Caffeine Ingestion.”International Journal of Sport Nutrition and
Exercise Metabolism10 (2000): 464–75.
Eskenazi, B. “Caffeine—Filtering the Facts.”New England Journal of Medicine341 (1999):
1688–89.