Ectrodactyly

In 1980, the US Food and Drug Administration cautioned pregnant women to limit their intake of coffee. This advice was based on animal studies showing teratogenic effects in several species when very high doses of caffeine were consumed. Since that time, substantial epidemiologic research has been completed. This review, written by researchers from the International Agency for Research on Cancer and the University of Pelotas, Brazil, describes the human studies on possible reproductive hazards of coffee drinking.

In 1981, three cases of ectrodactyly (a serious limb malformation) were reported in infants born to women who had consumed large amounts of coffee during pregnancy. Since ectrodactyly was also observed in animal studies of the teratogenicity of caffeine, these cases aroused great interest. However, the epidemiologic evidence does not support this anecdotal finding.

Three high-quality epidemiologic studies have failed to find an association between coffee drinking and congenital defects. Two other, less rigorous studies did show some evidence of an effect, but "their data should probably be reexamined at this time." No specific association with ectrodactyly was seen in any of these studies.

The reviewers conclude that the overall epidemiologic evidence does not implicate coffee as a human teratogen, at least at low or moderate levels of consumption. It should be recognized, however, that little is known about the effects of high levels of coffee intake (eg, eight or more cups per day), and that a threshold effect is possible.

Ten epidemiologic studies have examined the possible effect of coffee consumption on birth weight. All found an inverse relationship, which was statistically significant in seven studies.

These findings are difficult to interpret, because many demographic, medical, social, and behavioral characteristics (particularly cigarette smoking) are correlated with both birth weight and coffee consumption. Overall, the data suggest that coffee drinking during pregnancy has a small adverse effect on birth weight, which is most likely to be relevant for women who are already at risk of having a low-birth-weight infant for other reasons.

An association between coffee consumption and spontaneous abortion was found in three studies but not in three others. Several of these studies had important methodologic limitations, and the current evidence does not seem sufficient to support a link between coffee drinking and spontaneous abortions.

Three of four studies on fertility have reported delayed time to conception among women who drank moderately large amounts of coffee while attempting to become pregnant. [Editor's note: a fifth study, which found delayed conception only in coffee/tea drinkers who also smoked cigarettes, is described in this issue of NRN.] These studies "raise an interesting hypothesis, but an association is yet to be proved."

The reviewers conclude that a warning for pregnant women to limit coffee drinking is "probably justified," on the basis of the birth weight data. They suggest a maximum intake of two cups of percolated coffee per day during pregnancy. They also advise that "it is probably reasonable to suggest to women who have difficulty becoming pregnant that they limit their coffee intake."

Steven A Narod, Silvia de Sanjose, and Cesar Victora, Coffee During Pregnancy: A Reproductive Hazard? American J Obstetrics & Gynecology 164(4):1109-1114 (Apr 1991) [Reprints: Silvia de Sanjose, MD, PhD, International Agency for Research on Cancer, 150 Cours Albert Thomas, Lyon, France 69372]

COPYRIGHT 1991 Frost & Sullivan
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