Can marijuana use during pregnancy harm a baby?

pregnant woman using marijuana

By Crystal Grimes, NP, APN, MSN

Obstetrics & Gynecology Nurse Practitioner in Revere, Mass.

pregnant woman using marijuana

Using marijuana while pregnant or breastfeeding is not safe for developing babies.

Marijuana is a hot topic, as new debates about its safety and legalization crop up every week. I have conversations with my patients every day about marijuana use during pregnancy.

A study published in January 2017 found that the number of pregnant women who said they used marijuana in the past month rose from 2.4 percent in 2002 to nearly 3.9 percent in 2014. It’s safe to say these numbers are low, because many women will not admit to using marijuana during pregnancy.

I also suspect those numbers are even higher in Massachusetts, where the percentage of residents age 18 and older who said they used marijuana in the past month (11.91 percent) was higher than the national average (8.45 percent).

There are many reasons women use marijuana during pregnancy, including to lessen the effects of morning sickness. Many simply don’t think it’s a big deal, especially in moderation. Or friends have told them they used it during pregnancy and their babies were OK.

Women and their partners need to know that it’s never OK to use marijuana during pregnancy, and it’s important to be honest with your healthcare provider. There is just too much we don’t know about how it affects an unborn baby or a newborn while breastfeeding.

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What we know: How marijuana use during pregnancy may affect your baby

If you’re using marijuana, so is your baby. Much of what you put into your body reaches the baby through the placenta, and marijuana is no different. THC, or tetrahydrocannabinol, is the chemical in marijuana that gets you high. It acts on a receptor in the brain that is present in a fetus as early as 14 weeks, or toward the end of the first trimester.

Initial studies support our recommendations to stay away from marijuana while pregnant. It has been linked with lower birthweights and placement in a neonatal intensive care unit, often for preterm birth (birth 37 weeks or earlier).

Marijuana’s effects are mainly seen in the brain development of these children as they grow up. So, while your baby may seem fine at birth, problems may develop over the years.

The American Congress of Obstetricians and Gynecologists discourages marijuana use during pregnancy. Additional studies have shown that children exposed to marijuana in the womb had:

  • Decreased attention span
  • Increased risk of behavioral problems
  • Low scores on tests of visual problem solving, visual-motor coordination, and visual analysis
  • Poor reading and spelling scores

And your partner’s marijuana use matters, too. Secondhand exposure can harm your unborn baby. Ask anyone using marijuana to leave the room or go outdoors. Or bring them along to your prenatal appointment. I don’t mind being the “bad guy” and telling them to not use it around you! Also, if you are trying to get pregnant, be aware that marijuana use can reduce sperm count and mobility.

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Why not to use marijuana to treat pregnancy-related symptoms

Some of my patients tell me they turn to marijuana to reduce the nausea and vomiting that often occurs in the first trimester.

But there are safer treatments for this. Talk to your healthcare provider about:

  • Dietary changes, such as avoiding fatty or spicy foods
  • Prescription medications
  • Taking ginger (whether in a candy or drink) or vitamin B6
  • Alternative therapies such as acupuncture

The same goes for using marijuana to manage stress or anxiety. Your healthcare provider can suggest other options, such as safe medications, exercising or counseling.

Using marijuana while breastfeeding

After your baby is born, it still may not be safe to use marijuana. It can accumulate in breast milk, but we aren’t sure how much is passed on to the baby. As for its effects, some studies have shown it can result in decreased motor development, lethargy, and shorter feeding times. But again, we just don’t know for sure how much marijuana in breast milk can affect a baby, so I recommend avoiding it completely.

I find that once I explain to women who visit my clinic in Revere about the potential dangers of marijuana use during pregnancy, many quit. It’s important to find a healthcare provider who listens to you, is non-judgmental, answers the hard questions, and works with you to make necessary changes.

You won’t get into trouble if you talk to me about marijuana use. The recently enacted Massachusetts law that legalized marijuana included language that states a parent’s marijuana use can’t be the primary reason to take away custody or parental rights. There must be corresponding evidence that the parent’s actions related to marijuana have created a dangerous environment for the child.

If you need help to stop using marijuana during or after pregnancy, be honest with your healthcare provider when they ask about alcohol, tobacco, or drug use. I simply want to give you the information you need to make good decisions for your pregnancy.

Tags: family health, OB/GYN, Revere, women's health

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