For each monthly cycle, women who had used cannabis products–marijuana or hashish–in the weeks before pregnancy, or who had positive urine tests for cannabis use, while trying to conceive were 41% less likely to conceive than non-users. Similarly, a smaller proportion of cannabis users than non-users became pregnant during the study–42% versus 66%. The study found no differences in miscarriage rates between users and non-users who had achieved pregnancy.
The authors noted that although the findings suggest cannabis could affect women’s fertility, they should be tempered with caution as the study observed a relatively small number of cannabis users. However, the authors say their results suggest that women trying to conceive should exercise caution with cannabis use until more definitive evidence is available.
The study was published online in Human Reproduction.