Counsel against marijuana use in pregnancy, breastfeeding
Sheryl A.Ryan, M.D., FSAHM, FAAP, Mary E.O’Connor, M.D., M.P.H., FAAP and Seth D.Ammerman, M.D., FSAHM, DABAM, FAAP
AAP Clinical Report
Marijuana is one of the most widely used substances among pregnant women in the U.S.,
and pediatricians need to be able to counsel young women about its effects.
A new AAP clinical report recommends that pediatricians advise adolescents and women
of childbearing age to abstain from marijuana use while pregnant or breastfeeding
due to potential adverse consequences to the fetus, infant or child.
The report Marijuana Use During Pregnancy and Breastfeeding: Implications for Neonatal and Childhood
Outcomes, from the Committee on Substance Use and Prevention and Section on Breastfeeding,
is available at https://doi.org/10.1542/peds.2018-1889 and will be published in the September issue of Pediatrics.
Social media tout the use of marijuana for severe nausea associated with pregnancy,
and its legalization in some areas may give the false impression that it is safe.
At press time, nonmedical marijuana use was legal in nine states and the District
of Columbia for adults 21 years and older. Medical marijuana was legal in 30 states
and the district.
Consequently, more women are using or contemplating using marijuana while pregnant
and breastfeeding. Recent data show the prevalence of “past month” marijuana use among
pregnant women 18-44 years of age increased from 2.4% in 2002 to 3.9% in 2014, with
7.5% of pregnant 18- to 25-year-olds reporting use.There are no national data on use by pregnant teenagers.
The clinical report discusses how cannabinoids can cross the placenta and affect fetal
development, as well as concerns about pregnancy outcomes and long-term consequences
for the infant or child exposed to marijuana in utero. The understanding of the endocannabinoid
system and its role in the development of neural circuitry early in fetal life also
provides theoretical justification for the potential of marijuana substances, particularly
tetrahydrocannabinol (THC), to affect neurodevelopment.
Due to ethical and legal constraints, there are no randomized trials of marijuana
use during pregnancy and breastfeeding. Consequently, all data are from observational
studies. The report summarizes these data, including a recent meta-analysis to determine
the effect of marijuana exposure during pregnancy while controlling for tobacco use
and other confounders, such as other drug use.
The authors of the meta-analysis stated that the increasing frequency of marijuana
use during pregnancy may play a role in risk for adverse neonatal outcomes. They cautioned,
however, that women who use marijuana more frequently also are more likely to use
higher amounts of tobacco and other drugs, which could not be accounted for completely
in their review.
Two longitudinal studies have followed cohorts of infants prenatally exposed to marijuana
through adolescence and early adulthood; these studies were limited in their ability
to control for environmental and sociodemographic variables.
Despite the limitations, the observational studies indicate reason for concern, particularly
in fetal growth, early neonatal behaviors and long-term neurodevelopmental and behavioral
consequences of prenatal exposure to marijuana. Further, these studies were conducted
when marijuana had a much lower potency than what is available today. Thus, the adverse
consequences of prenatal exposure today may be much greater than what has been reported
Impact on breastfeeding
There are little data on the effect of marijuana use while breastfeeding.
Breastfeeding has numerous health benefits for the mother and the infant, particularly
the preterm infant. Limited data show that THC does transfer into human milk, but
there is no evidence for the safety or harm of marijuana use during lactation.
Additional concerns are that infants exposed through breastfeeding also may have been
exposed during pregnancy and through inhalation of marijuana smoked in their presence.
Recommendations for pediatricians
Inform adolescents and women of reproductive age about the lack of definitive research.
Counsel about concerns regarding potential adverse effects of THC exposure, including
passive smoke, on pregnant women and fetal, infant and child development. Include
marijuana when discussing the need to abstain from tobacco, alcohol and other drugs
Counsel pregnant women who are using marijuana or other cannabinoid-containing products
to treat a medical condition, nausea and vomiting during pregnancy — or who are identified
during screening as using marijuana — about the lack of safety data and the possible
adverse effects of THC on the developing fetus.
Explain that even where marijuana is legal, pregnant women can be subject to child
welfare investigations if they have a positive marijuana screen result.
Note that data are insufficient to assess the effects on infants who are exposed to
maternal marijuana while breastfeeding. Inform women of the potential risk of exposure
during lactation and encourage them to abstain from using any marijuana products while
Encourage women who never have used marijuana to remain abstinent while pregnant and
Work with state/local health departments if legalization of marijuana has occurred
or is being considered to help with constructive, nonpunitive policy and education
Dr. Ryan is chair of the AAP Committee on Substance Use and Prevention (COSUP), Dr.
O’Connor is a member of the AAP Section on Breastfeeding Executive Committee, and
Dr. Ammerman is a former member of COSUP. They are co-authors of the clinical report.