Researchers have reported results of a large, randomized clinical trial that provides the most statistically powerful evidence to date of the advantages for young children if their mothers take supplements of choline, an essential nutrient, during pregnancy.

Children of mothers who took choline supplements while pregnant had fewer social withdrawal problems and increased cognitive test performance through age 4 compared with children whose mothers received placebo pills.

Maternal choline supplementation as a potential preventive measure to reduce the risk of mental illness in offspring has been an important focus of the research career of Robert Freedman, M.D., a member of BBRF’s Scientific Council, winner of the 2015 BBRF Lieber Prize, and 2006 and 1999 BBRF Distinguished Investigator. Dr. Freedman, at the University of Colorado Denver School of Medicine, has conducted pioneering studies helping to explain implications of a major transition in the fetal brain that occurs just before birth.

This transition, which marks the emergence of the maturing brain’s capacity to modulate, or dial down, the activity of excitatory neural communication, is an essential step if the newborn brain is not to be overexcited or hyperactive. Hyperactivity is one of the suspected aspects of brain dysfunction that may contribute to a number of mental illnesses, including schizophrenia, attention-deficit hyperactivity disorder (ADHD), and autism spectrum disorder (ASD).

The brain’s emerging inhibitory capacity, Dr. Freedman and colleagues have discovered, is partly dependent upon the action of choline during the fetal period. In addition to its essential role in enabling brain cells to build cell walls, choline engages receptors that are abundant in the placenta and fetal brain. These are called alpha-7 nicotinic cholinergic receptors. Variations in the gene that encodes the receptor, called CHRNA7, have been linked with increased risk for schizophrenia, ADHD, and autism.

A maternal deficiency of choline, Drs. Freedman and colleagues have proposed, prevents or impairs the maturation of fetal neurocircuits, including inhibitory circuits, possibly contributing to pathology seen in these disorders.

As they have pointed out, levels of maternal choline dip naturally during the second trimester of pregnancy, making it a period of particular vulnerability for the fetus. Although choline is found in a normal diet, and especially in meat, fish, and eggs, many pregnant women—estimates range from 20% to 50%—have choline deficiencies.

In the newly reported trial, published in the American Journal of Obstetrics and Gynecology, Dr. Freedman and colleagues randomized 206 pregnant women to receive either 9000 mg daily of phosphatidylcholine (the form of choline occurring naturally in food) or placebo pills, from the 16th week of gestation through delivery. Neural inhibition of the newborns was tested in the weeks after birth; then from 18 months to 4 years of age, the children were assessed by their parents on a standard behavioral checklist, to identify emerging issues with behavioral withdrawal and attention. The children also received IQ tests as a surrogate for cognitive development, at ages 3 and 4. Women in both phosphatidylcholine and placebo groups received prenatal vitamins with folic acid and specific dietary guidance to consume more choline-rich foods, the researchers noted.

The team also included: Amanda J. Law, Ph.D., BBRF Scientific Council, 2011 BBRF Baer Prize, 2006 BBRF Young Investigator; M. Camille Hoffman, M.D., MSCS, 2015 BBRF Baer Prize; and Sharon K. Hunter, Ph.D., 2003 BRF Young Investigator.

Data from 142 children, 71 whose mothers received choline and 71 whose mothers received placebo, were used in the analysis; different subsets were used in different aspects of the analysis. In the immediate post-birth test of cerebral inhibition, 70% of children whose mothers received choline (40 of 57) responded in a way that indicated normal fetal neurosynaptic development, compared with just 48% of children (22 of 46) whose mothers received placebo.

The same pattern—a clear separation of the two groups of children—was seen in the behavioral assessments measuring withdrawal. For children of women who had placebo, 24% (17 of 71) were rated 2 or greater on a “Withdrawn Problems” scale, compared to only 4% (3 of 71) children of women who had choline supplements. As the team notes, a rating of 2 reflects a single problem that occurs all the time—in this case, immature social behavior, withdrawal from activities with others, poor eye contact, failure to show or respond to affection, and little interest in other people—or two of these problems that occur some of the time.

“Withdrawn Problems” are often seen in children with autism spectrum disorder. In this study, 11 of 71 children, 10 of them male, exhibited behaviors, including language difficulties, often reported in ASD. 10 were born to mothers who had placebo, and only 1 to a mother who had choline supplements while pregnant.

In this study, in contrast with an earlier, much smaller trial of phosphatidylcholine supplements vs. placebo conducted by the same investigators, no statistically significant effect of phosphatidylcholine was observed on “Attention Problems”: in this cohort, children of mothers who took the supplements did not have significantly fewer problems of this kind. This may be due to the design of the current trial, and is likely to be revisited in future trials, for clarification.

A clear association between choline supplements and cognition was seen in the results of IQ tests given at ages 3 and 4. Twelve children had scores of 120 or higher (90th percentile +): 10 of 54 children (18%) whose mothers received choline supplements, and 2 of 49 (4%) whose mothers received placebo. The six children in the study whose IQ score was in the 10th percentile or lower at ages 3 and 4 had mothers who had received placebo in the trial.

The choline supplements have proven to be quite safe. No significant adverse effects or safety problems were reported for women or children. Nausea, vomiting, dizziness, and hypertension were not increased. The children were found to be physically normal at birth and through the end of the trial. Positive effects were found for children regardless of their mother’s mental health status.

The study also provided new support for when and how much of the supplements should be taken. In this trial the team did not continue phosphatidylcholine in mothers after they gave birth. The human breast sequesters choline to produce high milk concentrations, and thus postnatal supplements, in the team’s view, are not needed.

As for the question of dosage, the team said this: “Major prenatal vitamin manufacturers are already offering prenatal choline supplements with other prenatal vitamins. [Our] dosage suggestion is 6300 mg phosphatidylcholine or 900 mg choline daily in divided doses. The 8-week prenatal visit or preconception may be optimal starting times.”

The team uses phosphatidylcholine in its studies because it is the form of choline that one receives from food. But phosphatidylcholine is only 14% choline by weight, which means multiple large pills must be swallowed each day to achieve the desired dosage. “Choline salts in smaller tablets or liquid concentrates may be more acceptable to some women,” the team said, in which case a 900mg/day dosage is recommended.

The team’s dose recommendation, based on clinical trials, “is higher than current American College of Obstetricians and Gynecologists dietary guidelines. The favorable side effect profile [for phosphatidylcholine] makes higher doses possible and tolerable.” Three trials of similar size are recruiting women now, but results won’t be known for years. An even longer lag time applies to larger population studies extending into adolescence or adulthood, which will need to retrospectively compare children of women who did or did not use supplements. It took decades for such studies on prenatal folate to be concluded, setting to rest any questions about their immense public health importance.

Years ago, Dr Freedman offered this comment to BBRF about his research, which for years focused on the mechanisms that give rise to schizophrenia. “The larger story is that we’ve gone from learning ways in which the nervous system doesn’t work in schizophrenia to actually doing something to prevent it from happening.”