Smoking weed while pregnant: Is it safe?

By Rachel Nall, MSN, CRNA 

Reviewed by Valinda Riggins Nwadike

Safety | Possible side effects | Research challenges | Marijuana for nausea | Edibles and vaping | Outlook

Some pregnant women use marijuana, and researchers are still unsure how the drug can affect a fetus. As a result, most medical experts recommend refraining from smoking weed during pregnancy.

Marijuana is the illicit drug women most commonly take during pregnancy, and use is increasing in certain areas.

As drug laws are relaxing in some parts of the world, it is essential for researchers to determine when marijuana is safe to use.

In this article, learn about the possible risks of smoking weed while pregnant, as well as what the experts recommend.

Safety

Doctors advise against using marijuana during pregnancy, but many misconceptions persist.

Some people believe that because medical use is legal in some areas of the United States, the drug must be safe to use while pregnant.

Others may believe that smoking weed is dangerous, but that other forms of the drug, such as edibles, will not harm the fetus.

However, research shows that using any form of marijuana can affect a fetus's growth and development, according to the Centers for Disease Control and Prevention (CDC).

Marijuana comes from the Cannabis sativa or Cannabis indica plants. These plants contain a compound called tetrahydrocannabinol, or THC.

THC has mind-altering properties that can cause a heightened sensation — a "high."

Dr. Heather Bradshaw, a specialist in cannabinoid pharmacology at Indiana University's Department of Psychological and Brain Sciences, believes that there is no safe level of consumption, as the chemicals in marijuana may have lasting negative effects:

"We are on the cusp of understanding all of the effects of THC and CBD on the brain, although it is a little early to definitively state what is or isn't affected during exposure in development. However, some research suggests that early exposure of THC to the brain can increase chances of schizophrenia and affect motor development."

Marijuana use can also affect:

• memory
• sensations, such as the appearance of colors
• body movement
• thinking and problem solving

The drug is illegal in many places, but legal to use for medical purposes in some parts of the U.S. It is legal for recreational use in a small number of countries.

People may use medical marijuana to treat nausea, pain, and muscle spasticity.

Possible side effects

The possible side effects of marijuana use during pregnancy include:

Low birth weight

A meta-analysis of 24 studies involving pregnant women, marijuana use, and birth outcomes found a connection between low birth weight and maternal marijuana use.

Reduced birth weight is associated with low oxygen levels, difficulty maintaining body temperature, and breathing problems, among other complications.

However, not all of the studies in the analysis showed a connection between marijuana use and low birth weight.

The researchers also found that babies born to women who had used marijuana during pregnancy were more likely to require a stay in the neonatal intensive care unit, compared with those who had not been exposed to the drug.

A 2017 study of prenatal marijuana exposure and behavior in children also found a link to lower birth weight, especially in women who smoked cigarettes as well as marijuana.

Stillbirth risk

A 2013 study from the National Institutes of Health (NIH) considered women who experienced stillbirth at 59 American hospitals.

The researchers tested blood samples from the women and the umbilical cords. They determined that marijuana use was associated with a 2.3 times higher risk of stillbirth.

However, the researchers cautioned that it was difficult to separate the effects of smoking marijuana and tobacco. People often use the substances together, and tobacco can cause pregnancy complications.

Research challenges

Modern, large-scale studies on marijuana use and pregnancy do not exist because there are many ethical issues concerning the study of pregnant women and developing babies.

For example, it would be unethical to study the effects of marijuana by asking a group of pregnant participants to use the drug.

If the babies of these women had any congenital abnormalities or developmental problems, the researchers would be at fault for harming them.

As a result, most existing research involves women who reported using marijuana during pregnancy.

According to research from 2017, some potential effects include:

• impaired fetal growth
• increased rates of preterm deliveries
• increased rates of stillbirths
• potential neurodevelopmental issues, such as behavioral problems that develop later in life

However, it is difficult to prove that marijuana causes one or all of these effects because researchers cannot perform studies that control for other factors.

Marijuana for pregnancy nausea

Nausea, or morning sickness, is a common pregnancy symptom.

Some doctors prescribe medical marijuana to treat chemotherapy-related nausea, and the National Institute on Drug Abuse (NIDA) report that some women use marijuana as a means to combat pregnancy-induced nausea.

However, no research exists to prove that this is a safe or effective practice.

Also, nausea tends to occur in the earlier stages of pregnancy, when the drug is more likely to affect the developing fetus.

It is best to talk to a doctor about safe ways to reduce nausea and vomiting during pregnancy.

Edibles and vaping

Beyond smoking, some people use cannabis by vaping or consuming edibles, which are foods that contain the drug.

These forms of marijuana do not contain the harmful substances in tobacco, but the CDC say that they are still not safe to use.

These products contain active THC and other chemicals, and the medical community has yet to determine their effects on a fetus.

Outlook

The CDC, NIDA, and the American College of Obstetricians and Gynecologists do not recommend using marijuana during pregnancy.

While some studies have concluded that marijuana has no effects on a fetus, other studies have linked prenatal use with low birth weight and an increased risk of stillbirth. Therefore, doctors recommend avoiding it altogether.

If a pregnant woman is using marijuana and finding it challenging to quit, she should speak to a doctor or seek professional support elsewhere.

Women in the U.S., for example, can call the Substance Abuse and Mental Health Services Administration's 24-hour treatment referral line at 800-662-HELP (4357).

SOURCE: MEDICAL NEWS TODAY