December 19, 2016 -- A new study by researchers at Columbia University's Mailman School of Public Health found that the prevalence of past-month marijuana use among reproductive-aged women rose from 2.4 percent in 2002 to 3.9 percent in 2014, an increase of 62 percent. Past-month marijuana use was highest among those ages 18 to 25 years, reaching 7.5 percent in 2014, and significantly higher among those ages 26 to 44 years (2 percent). Findings are published in the Journal of the American Medical Association.
The researchers used data from the annual National Survey on Drug Use and Health for the years 2002 through 2014.
"Our results offer an important first step towards understanding trends in marijuana use among women of reproductive age," said Dr. Qiana Brown, postdoctoral research fellow in the Department of Epidemiology, and the study's first author.
Of the 200,510 women studied, 29.5 percent were ages 18 through 25 years and 70.5 percent were ages 26 through 44 years; 5 percent were pregnant. Increases over time did not differ by age. Past-year use was higher overall, reaching 12 percent in 2014, with similar trends over time. In nonpregnant women, prevalences of past-month use and past-year use were higher overall, with similar trends over time. Increases over time in past-month marijuana use did not differ by pregnancy status.
Between 2001 and 2013, marijuana use among U.S. adults more than doubled, many states legalized marijuana use, and attitudes toward marijuana became more permissive. Aggregated data for 2007 to 2012 showed that 4 percent of pregnant women and 8 percent of nonpregnant reproductive-aged women reported past-month marijuana use.
Earlier studies suggest that prenatal marijuana exposure may be associated with poor offspring outcomes including low birth weight and impaired neurodevelopment. The American College of Obstetricians and Gynecologists recommends that pregnant women and women contemplating pregnancy be screened for and discouraged from using marijuana and other substances.
"Although the prevalence of past-month use among pregnant women is not high, the increases over time and potential adverse consequences of prenatal marijuana exposure suggest further monitoring and research are warranted," said co-author Deborah Hasin, PhD, professor of Epidemiology at the Mailman School of Public Health and in the Department of Psychiatry at Columbia University Medical Center. "To ensure optimal maternal and child health, practitioners should screen and counsel pregnant women and women contemplating pregnancy about prenatal marijuana use," noted Dr. Brown.
Co-authors are Aaron Sarvet, Silvia Martins, and Melanie Wall, Mailman School of Public Health; and Dvora Shmulewitz, Columbia University Medical Center.
The research was supported by grants from the National Institute on Drug Abuse, grants T32DA031099, R01DA037866, R01DA034244. The authors report no financial conflicts of interest.
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