Cannabis use among women of reproductive age in the United States: 2002-2017.

Background: In this study of cannabis use in large nationally representative samples of United States (US) women aged 12-44 years, we evaluate variation by pregnancy month and by trimester. We also evaluate cannabis dependence, which might explain why some women continue using cannabis during pregnancy.

Methods: Large nationally representative samples drawn for the US National Surveys on Drug Use and Health included 12-44-year-old women asked about pregnancy month, cannabis use, and cannabis dependence (n = 381,199). For this research, we produced month-specific estimates across four-time intervals (2002-2005, 2006-2009, 2010-2013, 2014-2017).

Results: Overall from 2002 to 2017, estimates for non-pregnant women and for pregnant women in Trimester 1 indicate 7%-8% had used cannabis at least once in the 30 days prior to assessment. For pregnancy Month 1, the corresponding estimate is 11%, double Month 3 estimate of 5%. This degree of month-to-month variation is not seen for pregnant women in Trimesters 2 and 3, for whom estimates are 3% and 2%, respectively. Among women using cannabis during pregnancy, an estimated 19% have cannabis dependence, versus an expected value of 13% among non-pregnant women (p < .05).

Conclusion: Evidence of a possibly ameliorative pregnancy-associated reduction of cannabis use prevalence was seen by Month 3 during pregnancy. Cannabis dependence may help account for cannabis use early during pregnancy. Identification and outreach to reproductive age women with cannabis dependence might decrease prenatal cannabis exposure.