Marijuana and Pregnancy: What You Should Know Before You Use Marijuana

If you’re pregnant, you’ve probably heard a lot of conflicting information about marijuana. Some people say it’s natural, so it must be safe. Others say it helps with nausea or anxiety during pregnancy. And with legalization spreading across the country, it’s easy to assume marijuana is harmless.

But when it comes to pregnancy and breastfeeding, the science tells a different story.

Let’s break down what we actually know about marijuana use during pregnancy, why it matters for your baby, and some of the most common misconceptions people hear online and from friends.

First, Let’s Talk About the “It’s Natural” Myth

A lot of people assume marijuana is safe because it’s a plant. But plenty of natural things can be harmful during pregnancy—alcohol fermentation is natural, tobacco is a plant, and certain herbs can cause complications.

The issue isn’t whether marijuana is natural. The issue is how the active chemicals in marijuana affect a developing baby.

The main psychoactive ingredient in marijuana, THC (tetrahydrocannabinol), easily crosses the placenta. That means when a pregnant woman uses marijuana, THC enters the baby’s bloodstream and brain.

A developing baby’s brain is extremely sensitive to outside chemicals. Exposure during this critical time can affect how the brain forms and functions.

Common Misconception: “It Helps With Morning Sickness”

Some pregnant women consider marijuana for nausea, especially during the first trimester. While it may seem to provide temporary relief, marijuana has not been proven safe for treating pregnancy-related nausea.

In fact, regular marijuana use can lead to cannabinoid hyperemesis syndrome, a condition that causes severe, repeated vomiting.

There are safer, medically recommended treatments for nausea during pregnancy that don’t expose the baby to THC. If nausea is overwhelming, a healthcare provider can help find options that are safer for both mom and baby.

How Marijuana Affects the Baby During Pregnancy

Because THC crosses the placenta, the baby is exposed to the same chemicals as the mother. Research has linked prenatal marijuana exposure to several risks.

Short-Term Effects During Pregnancy

Babies exposed to marijuana in the womb are more likely to experience:

  • Low birth weight

  • Premature birth

  • Smaller head circumference

  • Increased risk of NICU admission

  • Possible changes in placental function that may affect oxygen and nutrient delivery.

These complications can affect a baby’s health immediately after birth and sometimes require additional medical care.

Long-Term Effects on Brain Development

The biggest concern researchers have is how marijuana affects the developing brain.

Studies suggest that children exposed to marijuana during pregnancy may have higher risks of:

  • Attention and learning difficulties

  • Memory problems

  • Impulsivity and behavioral challenges

  • Lower academic performance

  • Higher likelihood of substance use later in life

These effects may not show up right away. Some children appear healthy at birth but develop challenges later in childhood or adolescence.

Effects on the Pregnant Woman

Marijuana use during pregnancy can also affect the mother.

Possible effects include:

  • Increased dizziness or fainting

  • Impaired judgment and coordination

  • Increased heart rate

  • Potential interactions with other medications

  • Increased risk of mental health symptoms, including anxiety or depression in some individuals

Smoking marijuana also exposes the body to many of the same harmful chemicals found in tobacco smoke, which can affect lung health and oxygen levels.

What About Edibles, Vapes, or CBD?

Some people assume edibles, vaping, or CBD products are safer alternatives. Unfortunately, that’s not necessarily true.

  • Edibles still contain THC, which reaches the baby through the placenta.

  • Vaping still delivers THC and may expose users to harmful chemicals.

  • CBD products are not well regulated, and many contain small amounts of THC even when labeled otherwise.

Because these products aren’t tightly regulated, it’s often hard to know exactly what’s in them.

Marijuana and Breastfeeding

THC doesn’t just affect pregnancy—it can also pass through breast milk.

THC is stored in body fat, which means it can remain in breast milk for days or even weeks after use.

Babies exposed through breast milk may experience:

  • Sleepiness or sedation

  • Poor feeding

  • Potential effects on brain development

Major medical organizations, including the American Academy of Pediatrics and the American College of Obstetricians and Gynecologists, recommend avoiding marijuana while breastfeeding because of these risks.

If You’ve Already Used Marijuana During Pregnancy

First—don’t panic.

Many people use marijuana before realizing they’re pregnant. The most important thing is what you do moving forward.

If you’re pregnant and currently using marijuana, consider talking with a healthcare provider about safer ways to manage symptoms like nausea, stress, or sleep problems. The goal is support—not judgment.

Pregnancy is a time when small choices can make a big difference for your baby’s development.

The Bottom Line

Marijuana may be legal in many places, but legal doesn’t always mean safe during pregnancy or breastfeeding.

Because THC reaches the baby through the placenta and breast milk, marijuana use can affect growth, development, and long-term brain health.

If you’re pregnant or planning to breastfeed, the safest choice for your baby is avoiding marijuana altogether.

And if you have questions or concerns, reaching out to a healthcare provider can help you get accurate information and support for a healthy pregnancy.

Your health and your baby’s health matter. Getting clear, science-based information helps you make the best decisions for both of you.

Resources for Further Information:

1.       https://www.acog.org/clinical/clinical-guidance/clinical-consensus/articles/2025/10/cannabis-use-during-pregnancy-and-lactation?utm_source=chatgpt.com

2.       https://www.epocrates.com/online/article/acog-calls-for-universal-cannabis-screening-in-pregnancy-and-postpartum?utm_source=chatgpt.com

3.       https://jamanetwork.com/journals/jamapediatrics/article-abstract/2833505?utm_source=chatgpt.com

4.       https://www.cdc.gov/cannabis/health-effects/pregnancy.html