Human research has shown that some babies born to women who used marijuana during pregnancy display altered responses to visual stimuli, increased trembling, and a high-pitched cry, which could indicate problems with neurological development. Evidence is mixed as to whether marijuana use by pregnant women is associated with low birth weight or premature birth, although long-term use may elevate these risks.
Associations have been found between marijuana use during pregnancy and future developmental and hyperactivity disorders in children. In school, marijuana-exposed children are more likely to show gaps in problem-solving skills, memory, and the ability to remain attentive. (More research is needed to disentangle marijuana-specific effects from those of other environmental factors.)
Prenatal marijuana exposure is also associated with an increased likelihood of a person using marijuana as a young adult, even when other factors that influence drug use are considered.