December 27, 2000

Two recent studies suggest that caffeine may increase the chances for miscarriage early in pregnancy and that marijuana may act to prevent conception.

In a study published in The New England Journal of Medicine, researchers from the Karolinska Institute in Stockholm found that caffeine in the equivalent of one to three cups of American coffee a day increases the risk of miscarriages in the first 12 weeks of pregnancy by about 30 percent, and that five or more cups doubles the risk. (The equivalencies were adjusted for the typically stronger Swedish coffee.)

The study attempted to account for the effects of morning sickness, which keeps many women off coffee and which generally indicates healthy fetuses, thereby possibly accounting for more unhealthy fetuses among coffee drinkers. Even if somewhat skewed by morning sickness, the study's results were viewed as the strongest yet to suggest that pregnant women should avoid or limit caffeine in their diet.

The director of the study, Dr. Sven Cnattingius, suggested that pregnant women should curtail their consumption to two cups of American coffee per day.

In the other study, conducted by researchers at the State University of New York at Buffalo, and presented at the annual meeting of the American Society for Cell Biology, it was shown that chemicals in marijuana, cannabinoids, which mimic our bodies' own endocannabinoid compounds, may interfere with the sperms' ability to fertilize the woman's egg.

It has been known for years that male marijuana smokers have lower sperm counts, but this research suggests that smoking marijuana may have a greater impact on fertility than earlier believed.

THC--a cannabinoid in marijuana that makes people feel high--and an endocannabinoid called anadamide, both affect the fertilizing potential of human sperm. When the group measured the presence of anadamide in three reproductive fluids that the sperm comes into contact with on its path to fertilize an egg, they found that anadamide was present in all three fluids, suggesting that the endocannabinoid system regulates fertilization--and that smoking marijuana might upset that system.

All the subtle chemical changes that the sperm and egg undergo in order for there to be a successful fertilization are not fully understood, but, according to one of the researchers ``if you have a finely tuned regulatory system in the body and a person smokes marijuana--thereby taking in high concentrations of all these cannabinoid chemicals that bind to these various receptors in the body--this activity can have impacts on the normal function of that system.''

If the endocannabinoid system plays a big role in fertilization, which has yet to be proven, then the intaking of cannabinoids may well cause a percentage of the infertility in men and women for which the reason has yet to be determined.

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