Question: I have had a medical marijuana card for two years to treat my anxiety disorder. I recently found out that I am pregnant. What are the medical and legal risks if I continue to use marijuana as needed throughout my pregnancy?

Answer: With increasing medical uses for marijuana or cannabis, the research world is struggling to catch up and provide reliable, long-term data on the effects on the fetus and newborn.

Because cannabis is a prescribed medicine and is also legal for recreational use in many states, there is a perception that it is completely safe. People’s attitudes about marijuana and its potential to do harm have changed in the last decade. In a recent study, 19% of people perceived no risk from cannabis use during pregnancy; that number was only 4% 10 years prior.

In fact, there are risks to the unborn child, and both the American College of Gynecology and Obstetrics and the American Academy of Pediatrics advise against its use during pregnancy and breastfeeding.

The greatest concern is the potential for adverse effects on neurodevelopmental outcomes in newborns exposed to marijuana in utero. In other words, marijuana use during pregnancy can have negative effects on your baby’s developing brain.

Delta-9 tetrahydrocannabinol, the psychoactive component of marijuana, crosses the placenta and may affect the fetal endocannabinoid system in the brain. The endocannabinoid system is the part of the brain which monitors chemicals called neurotransmitters, which allow for communication across the brain and brain cell development.

Research also suggests that THC exposure can affect other areas of the brain including the amygdala, which helps to modulate reward and stress pathways.

Prenatal marijuana exposure has been shown to correlate with learning difficulties and developmental delays, as well as behavioral problems. In one Canadian study of 500,000 women who reported cannabis use during pregnancy, children had a 50% increased risk of autism spectrum disorder or other neurodevelopmental disabilities.

Beyond developmental outcomes, there is some evidence that marijuana use during pregnancy may increase the risk of preterm labor and of the baby being born small for gestational age. Unlike other psychoactive substances, there is no evidence of increased congenital anomalies with marijuana use.

More studies are needed to understand how timing (trimester), amount, strength and frequency affect the fetus and if any use is safe. THC also crosses into breast milk; for this reason the American Academy of Pediatrics and American College of Gynecology and Obstetrics do not recommend breastfeeding if you are using medical marijuana regularly.

Since you are taking marijuana lawfully, there are no legal risks to using it during pregnancy. At birth, the baby will likely have a toxin screen done on their urine and stool to determine the level and length of exposure. This is done only to care for the baby, not for legal reasons. If you make the decision to continue to take THC-containing products, be certain to share that information with your health care provider, as it can affect both the care of yourself and your baby.

Most states, including Pennsylvania, have required warning labels for medical marijuana products, advising against use while pregnant or breastfeeding.

The medical community advises against using cannabis during pregnancy. However, it is important that mental health concerns such as anxiety be addressed. Many people find being pregnant or being a new parent overwhelming and stressful.

Talk to your doctor about other ways, besides marijuana, to treat your anxiety that do not have as many risks and unknowns for your baby..

Dr. Pia Fenimore, of Lancaster Pediatric Associates, answers questions about children’s health. You can submit questions at Features@LNPnews.com.

What to Read Next