Nora D. Volkow, MD, director of the National Institute on Drug Abuse, and her associates reported in a letter on April 17, 2017 in the Annals of Internal Medicine that past-month prevalence of marijuana use among pregnant teens aged 12-17 years was 14% compared with 6.5% for their non-pregnant peers. This study involved 410,000 females aged 12-44 years between 2002 and 2015.