The Effects of Prenatal Exposure to Marijuana on Early Childhood Development: A Systematic Literature Review

Abstract

To assess the effect of prenatal marijuana exposure (PME) on the newborn, infant and early childhood development through review of current literature. A systematic literature review was conducted in the electronic database from 1996 to 2017 for the effects of PME and their fetal and early childhood outcomes. 7% of pregnant women self-reported using marijuana in the last year, while 16% of them reported near-daily use. Marijuana use has been reported to: a) interfere with normal placentation leading to miscarriage, preeclampsia and preterm labor through imbalance in Cannabinoid receptor type 1 (CBR1) stimulation; b) could lead to reduction of fetal growth and head circumference due to increased plasticity and resistance of uterine artery; c) be associated with impaired memory function, decreased verbal scores, increased aggression and hyperactivity, impaired abstract and visual reasoning; and d) could alter sleep patterns. Finally, there is no consensus regarding the effects of marijuana through breastfeeding exposure and no postpartum withdrawal effects in the newborn were reported. Research on the effects of PME on offspring has been limited by several confounding factors including self-reporting bias, concomitant use of other illicit drugs and psychosocial factors. Overall, PME may lead to negative consequences on the developing offspring. Public health messages to health care providers and pregnant women regarding the harmfulness of PME should become a high priority. Further research is needed to reinforce the existing data and examine additional potential negative effects on the developing child.