More evidence of risk
Commenting on the findings in an interview, Carla Marienfeld, MD, professor of psychiatry at the University of California, San Diego, said there is a growing body of evidence about risks from cannabis use during pregnancy, “a time where we already know the endocannabinoid system is very active in the developing fetus.”
She noted that the current study’s design makes it hard to know whether marijuana use causes worse depression.
However, “it clearly is not associated with helping to improve mood the way people who are using it believe or hope for,” said Dr. Marienfeld, who was not part of the research.
“The risk for harm in terms of worse mood for the pregnant woman or risks for harm to the developing fetus are being better understood with many new studies,” she added.
Yet as more and more states legalize medical marijuana, cannabis use during pregnancy is only going to rise, experts fear.
Cornel Stanciu, MD, of Dartmouth-Hitchcock Medical Center, Lebanon, N.H., who was asked for comment, noted that public endorsement for potential benefits of the marijuana plant is at an all-time high.
“To date, 33 states and the District of Columbia have responded by legalizing medical marijuana, with 10 states also having legalized recreational use of marijuana. The current practice is said to be ahead of science, as robust research has been hindered by strict regulations – and most epidemiological studies point toward harmful associations,” Dr. Stanciu said in an interview.
“Given the decreased perception of harm by the general public, women are certainly compelled to seek what they perceive as more natural self-management remedies,” he said.
A harmful habit
Dr. Stanciu cited a recent study conducted in Colorado in which researchers contacted cannabis dispensaries, identified themselves as being pregnant, and asked for guidance in managing pregnancy-related symptoms.
Almost 70% of dispensaries recommended products to treat symptoms, particularly in the vulnerable first trimester; 36% of them also provided reassurance of the safety profile. Very few encouraged a discussion with the physician.
“Consumption of cannabis during pregnancy results in cannabinoid placental crossing and accumulation in the fetal brain, as well as other organs, where it interferes with neurodevelopment and the endocannabinoid system,” he said.
In addition, retrospective studies have shown an association between prenatal cannabis ingestion and anemia in the mothers, low birth weight, greater risk for preterm and stillbirths, and increased need for neonatal ICU admissions.
“Children born to mothers who used cannabis during pregnancy have higher rates of impulsivity, delinquency, learning and memory impairment, as well as executive function deficits. There is also an increased association with proneness to psychosis during middle childhood,” Dr. Stanciu said.
When used during pregnancy, cannabis has been associated with increased anxiety in mothers, as well as increased risk for depressive disorders, incidence of suicidal ideations and behavior, and symptoms of mania and psychosis among those with bipolar and schizophrenia spectrum conditions. Cannabis has also been linked to coingestion of other substances and with alcohol use.
“So cannabis can pose harm, especially when used by those with affective disorders,” Dr. Stanciu said.
The study was funded by the National Institute on Drug Abuse. Dr. Richison, Dr. Marienfeld, and Dr. Stanciu have reported no relevant financial relationships.
A version of this article first appeared on Medscape.com