Study: Marijuana use in pregnancy linked to adverse outcomes

New research indicates that pregnant women's use of marijuana, either alone or in combination with tobacco, can adversely affect birth outcomes as well as behavioral issues in infancy.

The study, published in the March/April issue of the journal Child Development, analyzed a group of 250 infants, 173 of whom had been exposed to marijuana and/or tobacco during pregnancy. Infants who had been exposed to both substances, especially during the third trimester of pregnancy, tended to be smaller at birth and to be born earlier. Those infants exposed to both substances were more likely to be smaller in length and weight than those exposed only to tobacco in the third trimester.

The mothers in this study who showed symptoms of anger and aggression were more likely to use marijuana and tobacco throughout their pregnancy. They were more likely to give birth to infants who were irritable and easily frustrated, the researchers reported.

“Our results suggest that interventions with women who smoke cigarettes or use marijuana while pregnant should also focus on reducing stress and helping them cope with negative emotions,” said Rina Das Eiden, PhD, senior research scientist at the University at Buffalo Research Institute on Addictions.