BACKGROUND: Male marijuana use has increased steadily over the last decade, but its effect on risk of spontaneous abortion to our knowledge has not been studied.
METHODS: We analyzed data from Pregnancy Study Online (PRESTO), a North American prospective cohort study of pregnancy planners (2013-2019). During the preconception period, male and female participants completed baseline questionnaires on demographics, medical history, and behavioral factors, including marijuana use. Female participants identified pregnancy losses on bimonthly follow-up questionnaires and questionnaires completed in early and late pregnancy. We categorized frequency of male marijuana use in the 2 months before baseline as: none, <1 time/week, or ≥1 time/week. We estimated the association between preconception male marijuana use and spontaneous abortion, adjusting for male and female confounders.
RESULTS: Among 1,535 couples who conceived during follow-up, 9% of men reported preconceptional marijuana use <1 time/week and 8% ≥1 time/week. Nineteen percent of pregnancies ended in spontaneous abortion. Compared with no use, adjusted hazard ratios (HR) for male marijuana use were 1.1 (95% CI: 0.64-1.7) for <1 time/week and 2.0 (95% CI: 1.2-3.1) for ≥1 time/week. The association for ≥1 time/week persisted after restricting to couples where the female partner did not use marijuana (HR=2.0, 95% CI: 1.1-3.3), and was stronger for losses at <8 weeks' gestation (HR=2.5, 95% CI: 1.4-4.3) and among males aged ≥35 years (HR=4.1, 95% CI: 1.54-11).
CONCLUSIONS: Couples with male partners who used marijuana ≥1 time/week during preconception had greater risk of spontaneous abortion than couples with males who did not use marijuana.
