Study finds prenatal marijuana use can affect infant size, behavior

(University at Buffalo, May 10) Marijuana use – especially combined with tobacco use – during pregnancy is connected to low infant birth weight and behavior problems, according to researchers from the University of Buffalo.

Researchers looked at about 250 mothers and infants; 173 of the infants in the study were exposed to tobacco and/or marijuana before birth. They found that infants exposed to both substances were smaller in size and more likely to be born earlier than infants who were not exposed.

“We also found that lower birth weight and size predicted a baby’s behavior in later infancy,” the study’s lead researcher Dr. Rina Das Eiden said. “Babies who were smaller were reported by their mothers to be more irritable, more easily frustrated and had greater difficulty calming themselves when frustrated. Thus, there was an indirect association between co-exposure to tobacco and marijuana and infant behavior via poor growth at delivery.” Read more.