Marijuana use may make conception more difficult for women who smoke than those who don’t, according to a prospective cohort study from the National Institutes of Health (NIH).
The prospective cohort study focused on cannabis use via urinary metabolites and self-reporting during preconception, and whether it was associated with fecundability, live birth, and pregnancy loss. The findings, published in Human Reproduction, linked preconception cannabis use with reduced fecundability despite increased frequency of intercourse.1
The study evaluated 1,228 women aged 18 to 40 years with a history of pregnancy loss. The women were followed up with from 2006 to 2012 for up to 6 cycles while attempting pregnancy, and throughout pregnancy if they conceived. Self-reported preconception cannabis use and urinary tetrahydrocannabinol metabolites were recorded at baseline, after 6 months of follow-up or at the beginning of the conception cycle, and weeks 4 and 8 of pregnancy.
Researchers concluded that women with preconception cannabis use did have reduced fecundability (FOR 0.59; 95% CI 0.38, 0.92). They also found associations, although imprecise, with anovulation (RR 1.92, 95% CI 0.88, 4.18) and live birth (42% (19/45) cannabis users versus 55% (578/1043) nonusers; RR 0.80, 95% CI 0.57, 1.12). They did not find any association with preconception cannabis use and pregnancy loss (RR 0.81, 95% CI 0.46, 1.42).