This review is intended to provide practicing clinicians with an understanding of existing literature and recommendations for managing women who use marijuana during pregnancy because this will be an increasingly encountered clinical scenario. Marijuana is the most common illicit drug used in pregnancy, with a prevalence of use ranging from 3% to 30% in various populations. Marijuana freely crosses the placenta and is found in breast milk. It may have adverse effects on both perinatal outcomes and fetal neurodevelopment. Specifically, marijuana may be associated with fetal growth restriction, stillbirth, and preterm birth. There is an emerging body of evidence indicating that marijuana may cause problems with neurological development, resulting in hyperactivity, poor cognitive function, and changes in dopaminergic receptors. In addition, contemporary marijuana products have higher quantities of Delta-9-tetrahydrocannabinol (THC) than in the 1980s when much of the marijuana research was completed. The effects on the pregnancy and fetus may therefore be different than those previously seen. Further research is needed to provide evidence-based counseling of women regarding the anticipated outcomes of marijuana use in pregnancy. In the meantime, women should be advised not to use marijuana in pregnancy or while lactating. We recommend screen all women verbally for marijuana use at intake to obstetrical care and consider rescreening later in pregnancy. The review suggests a need for healthcare provider training on potential consequences of perinatal marijuana use and communication skills for counseling patients about perinatal marijuana. An increasing number of states are passing or considering medical marijuana laws. The goal of this document is to address the public health system's responsibility to educate physicians and public about the impact of marijuana on pregnancy and to establish guidelines that discourage the use of medical marijuana by pregnant women or women considering pregnancy.Read More