Researchers collected data on almost 12,000 children enrolled in the Adolescent Brain Cognitive Development study, a long-term study exploring how children’s brains develop. Of the children enrolled, 655 were reported by parents to have been exposed to marijuana in the womb.
The study authors analyzed data on the children’s brain function and whether they had psychotic-like experiences (such as hallucinations or delusional thinking), attention, social, or sleep problems at around 9 years old. They found that children exposed to pot prior to birth had more of these problems and lower brain function than children not exposed to marijuana during their mom’s pregnancy.
Next, the researchers adjusted for other factors that can influence children’s brains, such as whether the mom used alcohol and tobacco while pregnant, whether there was a family history of psychiatric disorders, and the family’s socioeconomic status. After accounting for these factors, the risks associated with marijuana use remained among kids exposed to marijuana in the womb after their moms realized they were pregnant (usually at around 7 weeks).
The study authors theorized that tetrahydrocannabinol (THC), the chemical in marijuana that causes a high, may interfere with the developing baby’s brain. This may be more likely to occur at around the 5- or 6-week mark, because that’s when a baby’s brain is thought to develop endocannabinoid receptors, they explained in JAMA Pediatrics.
It’s possible the study data wasn’t entirely accurate, as it relied on parents reporting marijuana use (moms may have been reluctant to disclose whether they used the drug). Also, there was no information on how much marijuana the moms used during pregnancy.
Nevertheless, other studies have found correlations between pot use during pregnancy and cognitive and behavioral problems in children. Prior research has shown that marijuana exposure in the womb may make it harder for children to learn and pay attention, and increase the risk of preterm birth.
Health experts, including the U.S. Surgeon General and those at the Centers for Disease Control and Prevention and the American College of Obstetricians and Gynecologists, urge women not to use marijuana in any form during pregnancy and while breastfeeding.
Learn more about the safety risks associated with marijuana use during pregnancy and about natural remedies for morning sickness that don’t pose a risk to your baby.