Study Finds Cannabis Use During Pregnancy Increasing in United States

Researchers have found that the number of women in the United States who use cannabis during pregnancy is increasing, according to a study published this week in the medical journal JAMA. Cannabis use during the first trimester of pregnancy was especially prevalent, researchers determined.

To conduct the study, researchers used self-reported data from the National Survey of Drug Use and Health from 2002 through 2017. The percentage of pregnant women who had used cannabis the month prior to completing the survey increased from 3.4 percent in 2002 to 7 percent in 2017. Past-month marijuana usage by women during the first trimester of pregnancy increased from 5.7 percent to 12.1 percent.

The researchers performing the study analyzed data from women 12 to 44 years old who responded to the survey. The respondents included 4,400 pregnant women and 133,900 women who were not pregnant at the time they participated in the survey. The study determined that women were using cannabis during pregnancy for both medical and nonmedical reasons.

Participants in the survey were asked about their current pregnancy status, their marijuana use during the past month, the number of days of marijuana use in the previous month, and daily or near daily use of marijuana, which was defined as more than or equal to 20 days in the past month.

The use of marijuana on a daily or near daily basis increased in total from 0.9 percent to 3.4 percent. Daily or near daily use during the first trimester increased from 1.8 percent to 5.3 percent, from 0.6 percent to 2.5 percent in the second trimester, and from 0.5 percent to 2.5 percent during the last trimester.

Medical and Nonmedical Use Reported

Beginning in 2013, the survey asked women if their cannabis use had been recommended by a health care professional. Between the years of 2013 and 2017, only 0.5 percent of marijuana use over the previous month was considered strictly medical and had been recommended by a health care professional.

“Although many states have approved cannabis for nausea/vomiting (including in pregnancy), the results suggest that clinicians might not recommend it during pregnancy,” the authors of the study wrote.

They also noted that the low percentage of cannabis use that had been recommended by a health care professional may reflect the advice of the American College of Obstetricians and Gynecologists to “discontinue marijuana use” during pregnancy.

The effects of cannabis on a developing fetus have not been fully determined, but the U.S. Centers for Disease Control and Prevention warns that marijuana use during pregnancy could result in developmental problems and low birth weight.

Most birth defects occur during the first trimester of pregnancy, according to the CDC. As a result, any potential effects of cannabis on a fetus could be “more pronounced in women who consume marijuana frequently, especially in first and second trimesters,” according to the authors of the study.

A separate study released this week found that there may be a correlation between cannabis use during pregnancy and preterm births.