The doctor and her colleagues investigated the effects of grass on 221 couples that underwent in vitro fertilisation (IVF) or gamete intrafallopian transfer (GIFT) treatment for infertility. The study showed that 10% of men and women smoked marijuana in the year before the fertility procedure, and 3% of women and 0.5% of men reported smoking it the day before the procedure.
It was studied that if a woman had used marijuana over a longer period in her lifetime it would reduce the number of eggs that could be retrieved and the number of embryos that could be transferred. Women who smoked marijuana during the year before the procedure had 25% fewer eggs and about one fewer embryo transferred, when compared with women who didn't smoke during that year, the researchers noted. Similarly, it was found that smoking marijuana by the man during the year before the procedure was associated with approximately one fewer embryo transferred. And any lifetime use of marijuana by both partners was associated with a 19% decrease in eggs retrieved, when compared with couples that never smoked marijuana.
The group also found that if the man or the woman had ever used marijuana, their infant had a significantly lower birth weight, as compared with couples that had never used marijuana. This effect seemed to increase with higher or more recent marijuana use. Marijuana has been implicated with low birth weight, although the results are inconsistent, she stated. However, she also said that this are the initial reports and that their findings need to be verified by larger studies.
