, according to a recent clinical report published in the journal Pediatrics.
“The fact that marijuana is legal in many states may give the impression the drug is harmless during pregnancy, especially with stories swirling on social media about using it for nausea with morning sickness,” Sheryl A. Ryan, MD, FAAP, Chair of the American Academy of Pediatrics (AAP) Committee on Substance Use and Prevention, stated in a press release. “But in fact, this is still a big question. We do not have good safety data on prenatal exposure to marijuana. Based on the limited data that do exist, as pediatricians, we believe there is cause to be concerned about how the drug will impact the long-term development of children.”
The rate of marijuana use is increasing among pregnant women 18 years to 44 years old is increasing, the committee said, with 3.84% of women in 2014 within that age range using marijuana within the past month compared with 2.37% in 2002. Among women who were between 18 years and 25 years old, the rate of marijuana use within the past month was 7.47% in 2014.
The committee also noted research has shown cannabidiol exposure in the short term may impact placental permeability to “pharmacologic agents and recreational substances, potentially placing the fetus at risk from these agents or drugs.” A more well-known substance in marijuana, delta-9-tetrahydrocannabinol (THC) crosses the placental barrier and can appear in fetal blood. Studies have reported any level of marijuana use among pregnant women put the mothers at risk of anemia, while their newborns had an increased risk of low-birth weight and neonatal intensive care unit (NICU) use. Further research has shown impaired mental development, executive function deficits, increased impulsivity and hyperactivity, behavioral problems, depressive symptoms, and greater rates of substance abuse among children exposed to marijuana.
“Many of these effects may not show up right away, but they can impact how well a child can maneuver in the world,” Dr. Ryan stated in the release. “Children’s and teens’ cognitive ability to manage their time and school work might be harmed down the line from marijuana use during their mother’s pregnancy.”
In a related study, Kerri A. Bertrand, MPH, from the department of pediatrics at the University of California in San Diego, Calif., and her colleagues studied cannabinoid concentrations in breastmilk donated to a human milk biorepository. The investigators analyzed 54 samples donated by 50 women who used marijuana while breastfeeding between 2014 and 2017 and determined whether substances such as delta-9-THC, 11-hydroxy-delta-9-tetrahydrocannabinol (11-OH-THC), cannabidiol, and cannabinol were present in breastmilk by performing liquid chromatography mass spectrometry electrospray ionization on the samples.
They found 34 of 54 samples (64%) had detectable delta-9-THC approximately 6 days after marijuana use (median concentration, 9.47 ng/mL; range, 1.01-323 ng/mL), while 5 of 54 samples (9%) had measurable concentrations of 11-OH-THC (range, 1.33-12.80 ng/mL) and 5 of 54 samples (9%) contained measurable cannabidiol (range, 1.32-8.56 ng/mL). Predictors of log delta-9-THC concentrations included number of hours since last use (-0.03; 95% confidence interval, -0.04 to -0.01; P equals .005), the number of times per day marijuana was used (0.51; 95% CI, 0.03-0.99; P equals .039), and the amount of time between sample donation and analysis (0.08; 95% CI, 0.00-0.15; P equals .038), researchers said.
“Because marijuana is the most commonly used recreational drug among breastfeeding women, information regarding risks to breastfeeding infants is urgently needed,” Dr. Bertrand and colleagues wrote in their study.
The authors of the AAP clinical report acknowledge no relevant conflicts of interest. The study by Bertrand and colleagues was supported by the University of California San Diego Center for Better Beginnings, a grant from the National Institutes of Health, and the Gerber Foundation.
SOURCE: Bertrand KA et al. Pediatrics. 2018 Aug 27;doi:10.1542/peds.2018-1076.
The study by Bertrand and colleagues should be commended for being among the first to analyze cannabinoids in breast milk, but there are still very important questions to be answered about marijuana use among women who breast-feed, Sheryl A. Ryan, MD, FAAP, wrote in a related editorial.
Questions remain about why one-third of participants in the study had no detectable cannabinoids in their breast milk, and a frame of reference is needed for the levels that did appear in the study, Dr. Ryan said. Data are also needed on how the cannabinoids “accumulate in the infant, how the infant metabolizes these substances, how quickly they are excreted, whether they accumulate, and thus how long these metabolites remain in the infant,” she said.
Dr. Ryan also questioned what to tell mothers who use marijuana but want to breastfeed their newborns, and noted guidelines from the AAP and the American College of Obstetricians currently recommend avoiding marijuana use entirely while breastfeeding.
“With their study, Bertrand et al. have provided additional and valuable support for those current recommendations. But the picture is incomplete without our understanding of what is happening at the level of those infants exposed to cannabinoid–containing breast milk,” Dr. Ryan said. “Hopefully, the calls for research to answer these important questions will not go unheeded.”
Dr. Ryan is from the Division of Adolescent Medicine and Department of Pediatrics at Penn State Health Children’s Hospital in Hershey, Penn. These comments summarize her editorial in response to Bertrand and colleagues. She reports no relevant conflicts of interest (Ryan SA. Pediatrics. 2018;142:e20181921).