Can marijuana use during and after pregnancy harm the baby?
Animal research suggests that the body's endocannabinoid system plays a role in the control of brain maturation, particularly in the development of emotional responses. Thus THC exposure very early in life may negatively affect brain development. Research in rats suggests that exposure to even low concentrations of THC late in pregnancy could have profound and long-lasting consequences for both brain and behavior of offspring.75 Human studies have shown that some babies born to women who used marijuana during their pregnancies respond differently to visual stimuli, tremble more, and have a high-pitched cry, which could indicate problems with neurological development.76,77 In school, children prenatally exposed to marijuana are more likely to show gaps in problem-solving skills, memory, and the ability to remain attentive.78,79 More research is needed, however, to disentangle marijuana’s specific effects from other environmental factors, including maternal nutrition, exposure to nurturing/neglect, and use of other substances by mothers.80 Establishing marijuana’s effects on prenatal development is important, because roughly half of U.S. pregnancies are unplanned, with the rate considerably higher for teens and young adults,81 so many women may use marijuana without knowing they are pregnant.
Furthermore, breastfeeding mothers are cautioned that some research suggests that THC is excreted into breast milk in moderate amounts. Researchers do not yet know what this means for the baby's developing brain.
This series of reports simplifies the science of research findings for the educated lay public, legislators, educational groups, and practitioners. The series reports on research findings of national interest.