Couples trying to conceive may be making the job harder if they consume marijuana, according to researchers in London.
An article in this week's Canadian Medical Association Journal, prepared by two researchers at Western University, calls for more research to be done on pot's impact on fertility. Dr. Sara Ilnitsky, a reproductive endocrinology and infertility fellow at the Schulich School of Medicine and Dentistry at Western University, and Stan Van Uum, an endocrinologist at Western, worked together on the article.
"Legalization will likely increase marijuana use among reproductive-aged men and women," Ilnitsky said in a CMAJ podcast. "We wanted to help and inform health care providers of what we do and do not know about marijuana's effect on fertility."
According to Ilnitsky and Van Uum, a 2015 study in Denmark found smoking marijuana more than once a week in the preceding three months was associated with a 29% reduction in sperm count. While Ilnitsky says the effect of marijuana on sperm counts is fairly well known, the effects on women's fertility are less understood. However, Ilnitsky's and Van Uum's article cites a study of 201 women in which ovulation was delayed by an average of 1.7 to 3.5 days among the 29 women in the study who used marijuana.
She cautions that even these studies have their limitations.
"The problem with these studies is that they over-rely on self-reported marijuana use, so we don't have information on THC dose and the frequency ranges they use are very broad," she said.
In the end, Ilnitsky and Van Uum say for most couples, marijuana use does not affect their ability to conceive.
"However, for couples with infertility, the changes in ovulatory function and sperm count associated with smoking marijuana could compound their difficulty with conceiving," the article said.
You can listen to the CMAJ podcast with Dr. Ilnitsky by clicking here.
