New York researchers suggest pregnant women who use cannabis, perhaps to relieve their stress and anxiety, may inadvertently be predisposing their babies to those two conditions.
Investigators from the Icahn School of Medicine at Mount Sinai and the City University of New York (CUNY) point out that legalization of recreational cannabis in different parts of the world brings with it the belief among many that “cannabis use is without significant health risks,” notes a statement from CUNY.
That may include pregnant and breastfeeding women. Indeed a study out of California two years ago found that the “frequency of cannabis use in the year before pregnancy and during pregnancy has increased in recent years.”
Despite greater acceptance in step with loosening restrictions, “the impact of maternal cannabis use on foetal and childhood development is not clear,” say authors of the latest paper, to soon be published in the Proceedings of the National Academy of Science.
That being the case, they examined placental gene expression and early childhood behaviour and physiology in a long-term study of 322 mother-child pairs, all of whom were drawn from an ongoing study of stress in pregnancy.
At about age six, hair samples from the children were taken to measure hormone levels, electrocardiogram recordings were used to gauge their heart function during a stress-inducing condition and parental surveys were employed to determine their behavioural and emotional functioning.
Compared to children of non-cannabis users, the children of mothers who used cannabis during pregnancy showed higher anxiety, aggression, hyperactivity and levels of the stress hormone cortisol.
Additionally, exposure was associated with a reduction in the high-frequency component of the change in time interval between heart beats and, for a subset of participants, the RNA sequencing of placental tissue collected at birth “revealed that maternal cannabis use was associated with lower expression of immune-activating genes,” which help provide protection against pathogens.
“The cannabis-related suppression of several placental immune-gene networks predicted higher anxiety in the children,” the university reports.
“Future studies are needed to examine the effects of cannabis on immune function during pregnancy as a potential regulatory mechanism shaping neurobehavioural development,” the authors write in the study abstract.
Yoko Nomura, the paper’s first author and a professor of psychology at CUNY, say in the university statement that cannabinoid signalling has been shown to play a role in modulating stress.
That said, “our study shows that in utero exposure to cannabis has the opposite effect on children, causing them to have increased levels of anxiety, aggression and hyperactivity compared to other children who were not exposed to cannabis during pregnancy,” Nomura reports.
With cannabis being more potent than in decades past, “our findings indicate that using it during pregnancy can have long-term impact on children,” notes Yasmin Hurd, Ph.D., senior author of the paper and director of the Addiction Institute at Mount Sinai.
“The study results underscore the need for non-biased education and outreach to the public and particular vulnerable populations of pregnant women regarding the potential impact of cannabis use,” Hurd adds.
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