Birth Defects

Concerned about the reports of chromosome breakages as a result of the use of marijuana and LSD, the National Institute on Drug Abuse convened special conferences on the subject in 1973 and 1974. They concluded that "it is still doubtful whether cannabis is a danger to human genetics and reproductive processes, under the conditions and in the doses commonly used by marijuana smokers." Supporters of this conclusion point out that if there were a link between marijuana and birth defects, the millions of marijuana users in America and elsewhere would by now have given birth to large numbers of deformed babies.
    The reason for the concern is that several studies have indeed suggested such a link. The best known is an article by Morton A. Stenchever, an obstetrician at the University of Utah, in the American Journal of Obstetrics and Gynecology in 1974. Stenchever claimed that a group of twenty women and twenty-nine men who used marijuana had almost three times as many chromosome breaks as a control group that did not use marijuana. More frighteningly, such chromosome damage did not appear to be related to the frequency or the quantity of marijuana smoked.
    Critics of the study point out that Stenchever did not take into account what other drugs the subjects may have been using; caffeine, aspirin, and Valium are all capable of inflicting chromosome damage. They also point out that even if marijuana does cause chromosome breaks, there is no evidence that such breakages will in turn cause birth defects.
    Here, as in other cases, different studies produce different results. Dr. Warren N Nichols of the Institute for Medical Research in Camden, New Jersey, checked the chromosomes of twenty-four occasional marijuana smokers and found them to be healthy. The subjects were then given measured doses of marijuana for either five or twelve days and their chromosomes checked again; they were still healthy. And the Jamaica study found that long-term marijuana smokers actually had a lower rate of chromosome damage than an equivalent group of nonusers.
    It is still not clear whether marijuana represents a danger to pregnant women. Research with rats suggests that if the dosage in rodents could be mathematically extrapolated to dosages in human beings, a woman would have to smoke over a thousand joints a day before the size of her baby would be affected.