Nutrient May Protect the Fetal Brain From Prenatal Marijuana Use

Megan Brooks

August 01, 2019

Choline, an essential micronutrient, appears to guard against fetal brain damage caused by prenatal marijuana exposure, new research suggests.

Investigators found in utero exposure to marijuana negatively affects the fetal brain as early as 10 weeks' gestation, a critical time for fetal brain development. However, eating choline-rich foods or taking choline as a supplement may protect the child from potential harm.

"In 2017, the American Medical Association (AMA) recommended evidence-based amounts of choline for all pregnant women," study investigator Robert Freedman, MD, University of Colorado Denver School of Medicine in Aurora, told Medscape Medical News.

"Our new report indicates that choline levels should be over 7 micromolar in early pregnancy, which most women can achieve by taking a supplement of 1 gram of choline or 7 grams of phosphatidylcholine daily. Both are available without prescription. We also recommend that women not use marijuana while pregnant," he added.

The study was published online yesterday in Psychological Medicine.

Rising Marijuana Use in Women

Despite warnings of marijuana's potential harms during pregnancy, its use in young women is rising. Many women use marijuana before they know they are pregnant and some continue to use it as a natural remedy for morning sickness, depression, and anxiety. 

The investigators evaluated the interaction of maternal choline levels and prenatal marijuana's effects on the offspring. Choline is an essential nutrient that is particularly important during pregnancy, as it affects fetal brain development and can help prevent birth defects.

Of the 201 women who enrolled in the trial, 162 had their newborns evaluated. Of the 162 women, 98 (60%) did not use marijuana, 26 (16%) reported using it only at the time of conception, 13 (8%) continued during the first weeks of gestation but had discontinued by week 10, and 25 (15%) continued use from conception to 10 weeks' gestation, and then with variable frequency until term.

One-month-old infants whose mothers continued to use marijuana beyond 10 weeks had decreased central nervous system inhibition (evoked potentials to repeated sounds, P < .05). At 3 months of age, children whose mothers continued marijuana use beyond 10 weeks' gestation had poorer self-regulation (P < .05).

Notably, say investigators, these adverse effects in infants were not present if mothers had higher gestational choline in the early second trimester. Higher maternal choline levels also correlated with improved duration of attention, cuddliness, and bonding with parents.

"Ideally, expectant parents will heed warnings about the adverse effects of prenatal marijuana use on their child, but, regardless of the parents' decision, clinicians have a dual obligation to respect their autonomy and to provide the best possible healthcare for the mother and fetus. Care would appear from this study to include enhancing the mother's choline level to protect the fetus's brain development," the investigators write.

Novel but Not Surprising

Commenting on the findings for Medscape Medical News, Taylor C. Wallace, PhD, adjunct professor in the Department of Nutrition and Food Studies at George Mason University in Fairfax, Virginia, said the results are "novel but not surprising."

"There is increasing evidence that the placenta is sensitive to choline supply throughout pregnancy. Optimal development and functioning of the placenta result in both maternal and fetal health," explained Wallace, who was not involved with the study.

"Choline has also been shown to increase infant plasma cortisol and ease babies' response to stress activity (eg, smoking marijuana)," Wallace noted. "Higher choline intakes seem to decrease markers of inflammation and help facilitate transport of nutrients across the placenta to the fetus. Higher maternal choline intake during pregnancy has been suggested to decrease the risk of neurological birth defects and schizophrenia."

The "kicker," said Wallace, is that the current study measured serum choline level, "which is not a good indicator of choline status. There actually is not a good measure of choline status at the moment."

He also cautioned that the study is observational and "cannot be used to ascertain cause and effect, although it is a really great study design and execution. There is a chance that mothers who smoke marijuana during pregnancy have other bad habits that could influence infant health and development."

Echoing Freedman, Wallace said, "no pregnant woman should be smoking marijuana or taking cannabidiol (CBD) products, as there is no data to suggest it is safe and most of the data hints to adverse effects."

The study was supported by the Institute for Children's Mental Disorders, The Anschutz Foundation, National Institutes of Health, and the National Institute of Child Health and Human Development. The authors have disclosed no relevant financial relationships. Wallace is founder and CEO of the Think Healthy Group, Inc.

Psychol Med. Published online July 31, 2019. Abstract

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