Marijuana harms development in the first trimester of pregnancy


If you are pregnant and using any form of cannabis product, consider quitting.

This is the result of a new study that found a significant health impact of marijuana use on fetal development from early in pregnancy.

“That’s why these findings are particularly important – people can often be well into the first trimester and not even know they’re pregnant,” said lead author Beth Bailey, professor of psychology and director of the research. in Population Health at the College of Medicine at Central Michigan University in Mount Pleasant.

“Our study digs in to look very specifically at a specific time in pregnancy – the first trimester. We found a significant decrease in birth weight of 154 grams. In terms of pounds, that’s about a third of a pound,” said she declared.

Although a third of a pound may not seem like much, such slight weight decreases from marijuana use have been linked to health problems as children get older, Bailey said.

“Low birth weight is one of the strongest predictors of a child’s long-term health and development,” she said. “These children are more prone to developmental delays, higher rates of ADHD (attention deficit hyperactivity disorder), learning disabilities, and higher rates of emotional problems.”

If exposure continued through the rest of the pregnancy, birth weight dropped a further 31 grams (0.07 pounds), according to the study. Additionally, newborn head circumference was reduced if marijuana use continued throughout pregnancy. A smaller head circumference could be a sign that the brain did not develop properly during pregnancy.

“Even when pregnant women stopped using marijuana in the third trimester, babies were born with around 1 centimeter (0.4 inch) smaller head circumference,” Bailey said. “What we tell women is that it’s not absolutely certain that your baby’s growth will be affected if you use marijuana. But we know that you are at considerably higher risk for this outcome.

While reducing levels of marijuana use during pregnancy is beneficial, it may not be enough to protect the developing baby, Bailey said, because scientists don’t yet have the research data to determine if there is a level of marijuana use that does not cause fetal harm. .

The safest recourse? “My advice to women is to avoid using marijuana at all during pregnancy and, if possible, stop using it before you get pregnant,” Bailey said.

The study, published Tuesday in the journal Frontiers in Pediatrics, used data from the medical records of 109 pregnant women who gave birth at an obstetrics clinic at Central Michigan’s College of Medicine. This data was compared with data from 171 people who did not use marijuana and served as a control group.

Pregnant women who used marijuana were significantly younger, more likely to be single and covered by Medicaid, and less likely to have an education beyond high school than those who did not use marijuana.

While the number of studies was small, the research was robust because marijuana use was verified by urine testing, said Brianna Moore, assistant professor of epidemiology at the Colorado School of Public Health in Aurora. . She did not participate in the study.

“The urine test for THC (tetrahydrocannabinol) is more objective than self-reporting, as pregnant women may not want to report that they use cannabis,” she said.

According to studies, self-reported cannabis use during pregnancy is around 7%, Moore added. However, a 2019 study that tested umbilical cords for TCH found that cannabis use during pregnancy could be as high as 22.4%.

Many pregnant women may use cannabis to treat pregnancy-related symptoms such as nausea and pain or as a “substitute” for prescription drugs like antidepressants, Moore said.

David Zalubowski/AP/FILE

Marijuana use can harm fetal development during the first trimester, a time when many people may not know they are pregnant.

“However, one study suggests that very few pregnant women (0.5%) use cannabis strictly for medical purposes,” Moore said. “There is work to be done to understand the contextual, social or individual factors that influence cannabis use during pregnancy.

“It would help identify techniques and tools to limit cannabis use during pregnancy,” she added, “such as mindfulness techniques to deal with stress or ‘triggers’ and medications on sale. free for nausea and the like.”

Marijuana use during pregnancy is on the rise, Bailey said: “With legalization, there seems to be the idea that it has to be safe because it’s legal, and so a lot of people continue to use it for the pregnancy.”

To compound the problem, studies in the 1990s didn’t look at specific trimesters and found little overall harm to a fetus from marijuana use, Bailey said. It is possible that some of the oldest information is currently circulating on social networks.

“Birth weight had only a minimal impact back then, and studies have shown subtle effects on long-term child development,” Bailey said. “However, what we’re seeing with legalization is that people are probably consuming more of it, and today we have strains of marijuana with higher THC levels, now that marijuana is grown commercially. We we see very significant effects on the fetus over the last 10 years of research.

The impact can be even worse when negative health behaviors are combined. Previous research has ‘pretty well established’ that smoking cigarettes during pregnancy has a greater impact on birth weight than exposure to marijuana,” Bailey said.

“But when women combine smoking cigarettes and marijuana, we see an even greater effect on birth weight than you would get from either of the two alone,” she said. declared.

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