Prenatal marijuana use can affect infant size, behavior

May 10, 2018

Science Daily/University at Buffalo

Smoking during pregnancy has well-documented negative effects on birth weight in infants and is linked to several childhood health problems. Now, researchers at the University at Buffalo Research Institute on Addictions have found that prenatal marijuana use also can have consequences on infants' weight and can influence behavior problems, especially when combined with tobacco use.

"Nearly 30 percent of women who smoke cigarettes during pregnancy also report using marijuana," says Rina Das Eiden, PhD, RIA senior research scientist. "That number is likely to increase with many states moving toward marijuana legalization, so it's imperative we know what effects prenatal marijuana use may have on infants."

Through a grant from the National Institute on Drug Abuse, Eiden studied nearly 250 infants and their mothers. Of these, 173 of the infants had been exposed to tobacco and/or marijuana during their mothers' pregnancies. None were exposed to significant amounts of alcohol.

Eiden found that infants who had been exposed to both tobacco and marijuana, especially into the third trimester, were smaller in length, weight and head size, and were more likely to be born earlier, compared to babies who were not exposed to anything. They also were more likely to be smaller in length and weight compared to babies exposed only to tobacco in the third trimester. The results were stronger for boys compared to girls.

"We also found that lower birth weight and size predicted a baby's behavior in later infancy," Eiden says. "Babies who were smaller were reported by their mothers to be more irritable, more easily frustrated and had greater difficulty calming themselves when frustrated. Thus, there was an indirect association between co-exposure to tobacco and marijuana and infant behavior via poor growth at delivery."

Furthermore, women who showed symptoms of anger, hostility and aggression reported more stress in pregnancy and were more likely to continue using tobacco and marijuana throughout pregnancy. Therefore, due to the co-exposure, they were more likely to give birth to infants smaller in size and who were more irritable and easily frustrated. The infants' irritability and frustration is also linked to mothers who experienced higher levels of stress while pregnant.

"Our results suggest that interventions with women who smoke cigarettes or use marijuana while pregnant should also focus on reducing stress and helping them cope with negative emotions," Eiden says. "This may help reduce prenatal substance exposure and subsequent behavior problems in infants."

The study appeared in the March/April issue of Child Development and was authored by Pamela Schuetze, PhD, Department of Psychology, Buffalo State College, with co-authors Eiden; Craig R. Colder, PhD, UB Department of Psychology; Marilyn A. Huestis, PhD, Institute of Emerging Health Professions, Thomas Jefferson University, Philadelphia; and Kenneth E. Leonard, PhD, RIA director.

https://www.sciencedaily.com/releases/2018/05/180510145924.htm

Prenatal cannabis use associated with low birth weights

The study, led by Colorado School of Public Health, shows a 50 percent increase in low birth weights among women who use cannabis during pregnancy

April 23, 2018

Science Daily/University of Colorado Anschutz Medical Campus

With marijuana use during pregnancy on the rise, a new study led by the Colorado School of Public Health shows that prenatal cannabis use was associated with a 50 percent increased likelihood of low birth weight, setting the stage for serious future health problems including infection and time spent in Neonatal Intensive Care Units.

"Our findings underscore the importance of screening for cannabis use during prenatal care and the need for provider counselling about the adverse health consequences of continued use during pregnancy," said the study's lead author Tessa Crume, PhD, MSPH, assistant professor of epidemiology at the Colorado School of Public Health at the University of Colorado Anschutz Medical Campus.

The study was published last month in The Journal of Pediatrics.

Crume and her colleagues utilized survey data from 3,207 women who participated in the Colorado Pregnancy Risk Assessment Monitoring System in 2014 and 15. They found the prevalence of marijuana use in the state of Colorado was 5.7 percent during pregnancy and 5 percent among women who were breastfeeding.

They also discovered that prenatal marijuana use was associated with a 50 percent increased chance of low birth weight regardless of tobacco use during pregnancy. Prenatal marijuana use was three to four times higher among women who were younger, less educated, received Medicaid or WIC, were white, unmarried and lived in poverty.

Crume said the numbers are surprising but also reflect changing attitudes toward marijuana, especially in a state like Colorado where it is legal.

"There is increased availability, increased potency and a vocal pro-cannabis advocacy movement that may be creating a perception that marijuana is safe to use during pregnancy," Crume said.

The National Survey on Drug Use and Health suggests that cannabis use among pregnant women has increased as much as 62 percent between 2002 and 2014. At the same time, the potency of the drug has increased six or seven fold since the 1970s along with the ways it is consumed -- eating, vaping, lotions etc.

"Growing evidence suggests prenatal cannabis exposure has a detrimental impact on offspring brain function starting in the toddler years, specifically issues related to attention deficit disorder," Crume said. "But much of the research on the effects of prenatal cannabis on neonatal outcomes was based on marijuana exposures in the 1980s and 1990s which may not reflect the potency of today's cannabis or the many ways it is used."

The study found that 88.6 percent of women who used cannabis during pregnancy also breastfed. The risk of cannabis to the infant through breastmilk remains unknown. Various studies have found that cannabinoids are passed to the baby in this way. One of the study's co-authors, Dr. Erica Wymore, MD, MPH, from Children's Hospital Colorado and the CU School of Medicine, is currently conducting a study to evaluate this issue.

The researchers recommend that health care providers ask pregnant women about their cannabis use and advise them to stop during pregnancy and lactation.

"Obstetric providers should refrain from prescribing or recommending cannabis for medical purposes during preconception, pregnancy and lactation," Crume said. "Guidance and messaging about this should be incorporated into prenatal care. And screening of pregnant women at risk for cannabis dependency should be linked to treatment options."

https://www.sciencedaily.com/releases/2018/04/180423125052.htm