Cannabis use rises among pregnant women despite mounting evidence of fetal harm
Health experts and medical societies warn there is no known safe amount of cannabis in pregnancy as use increases, particularly in the first trimester
Cannabis use among pregnant women is increasing, especially during the first trimester, even as medical experts and national professional societies warn of potential harms to the fetus and the mother, according to federal survey data and recent research.
The National Survey on Drug Use and Health, published by the Substance Abuse and Mental Health Services Administration, shows rising use of marijuana products among pregnant people. Women report turning to cannabis to treat pregnancy-related symptoms such as nausea and vomiting, insomnia, pain, stress and anxiety. A recent University of Florida study found that roughly one in six women admitted to using marijuana or a cannabidiol (CBD) product while pregnant, and about half of those users were unaware of the risks associated with prenatal use.
Medical specialists say misconceptions about safety are common. Cannabis contains two primary compounds: tetrahydrocannabinol (THC), which produces psychoactive effects, and CBD, which does not have the same intoxicating properties, said Dr. Alta DeRoo, chief medical officer at the Hazelden Betty Ford Foundation. Modern marijuana products often have substantially higher concentrations of THC than those available in the 1970s, a change that may render older studies less applicable to today’s products.
There is limited clinical research on drug safety in pregnancy: a public health study noted that fewer than 1% of drug trials over the past 15 years enrolled pregnant patients. Because of the scarcity of evidence about safe doses, potencies and timing of exposure, major organizations including the American College of Obstetricians and Gynecologists, the American Society for Reproductive Medicine and the American Academy of Pediatrics recommend not using cannabis when pregnant or trying to conceive.
"There is no known safe amount of cannabis to use in pregnancy," said Dr. Jamie Lo, an associate professor of obstetrics, gynecology and urology at Oregon Health & Science University. "I advise my patients to consider safer alternatives to treat their symptoms in pregnancy — or for those who cannot abstain, at least try to reduce their frequency of use." Lo’s research focuses on cannabis and reproductive health.
Studies have found that THC crosses the placenta and that endocannabinoid receptors appear in the fetal brain beginning in the third month of pregnancy. Several analyses have linked prenatal cannabis exposure to adverse birth outcomes. A review published in May that synthesized 51 studies reported associations between maternal cannabis use and a higher risk of preterm birth and a roughly 75% increased risk of low birth weight. Other research has connected prenatal exposure to reductions in fetal weight and head circumference and to higher rates of neonatal intensive care admissions.
Pregnant people who smoke marijuana may also experience lower oxygen levels while inhaling, which can contribute to respiratory problems. Any degree of intoxication can impair judgment and coordination, increasing the risk of falls and injuries during pregnancy. Longitudinal and observational studies have reported associations between prenatal cannabis exposure and later difficulties with attention, memory and learning in children.
Health professionals also caution that cannabis carries the potential for dependence. "Cannabis use disorder is continued cannabis consumption despite negative consequences, such as failing role obligations, impaired relationships, giving up important activities and using [drugs] in physically hazardous situations," said Dr. Tiffany Benjamin, a psychiatrist in San Francisco who has presented on clinical considerations of cannabis use. Acute effects of cannabis intoxication can include increased heart rate, dry mouth, red eyes, increased appetite, delayed reaction time, impaired concentration and, in some cases, anxiety or paranoia.
Consumer confusion has increased as hemp-derived CBD products and micro-dosed offerings become more widely marketed. Entrepreneurs in the hemp and wellness space report frequent inquiries from pregnant customers about product safety. Kim Gamez, founder of SOBER(ISH), an online hemp marketplace, said she is often surprised by how many women ask whether such products are safe during pregnancy or while nursing. Hemp is a cannabis plant variant, but its products can still raise safety questions in the absence of pregnancy-specific data.
Clinicians say counseling about cannabis should be part of prenatal care. Providers are urged to ask patients about all substance use, including cannabis and hemp products, and to offer evidence-based alternatives for symptom management when appropriate. Given the limited safety data, public health authorities and medical groups recommend avoiding cannabis use during pregnancy and among people trying to become pregnant.
Researchers and clinicians emphasize the need for more rigorous studies that include pregnant people to guide clearer recommendations. Until firm evidence about dose, timing and product-specific risks is available, medical societies advise abstaining from cannabis in pregnancy to reduce the risk of poor neonatal outcomes and longer-term developmental problems.
