How Marijuana Affects You, Your Pregnancy & Your Baby

Do you know how marijuana can affect your pregnancy and your baby?

Marijuana (cannabis) is the most commonly used substance in pregnancy, according to the National Survey on Drug Use and Health from the National Institute on Drug Abuse. Experts estimate that as many as 10% of pregnant women in both the US and in Europe use marijuana at some point or in some form in pregnancy.

Healthcare providers are advised by the American College of Obstetricians and Gynecologists to not prescribe medical marijuana in the preconception, pregnancy, postpartum or breastfeeding periods. Medical marijuana is now legal in 19 states, and legislation is pending in multiple other states. None of these states recommend or approve cannabis use during pregnancy, and some states have considered passing laws that include penalties up to incarceration for pregnant women who drug screen positive at birth. In 2014, Tennessee became the first state to pass legislation that criminalizes drug use during pregnancy.

Marijuana is still considered an illegal drug at the federal level, and it’s not regulated by the Food and Drug Administration (FDA).

If you use marijuana, baby uses marijuana

The major active compound in all cannabis products is commonly known as THC. This compound quickly crosses your placenta, meaning if you’re using marijuana, your baby is also using marijuana — only baby receives a blood-level concentration of an equivalent or higher dose of THC than you’ve received. Cannabis can be detected in both your baby’s cord and urine or stool after birth, and while in your womb, it continues to circulate in your baby’s blood for up to a full month.

Marijuana affects your nervous system in two ways: In low doses, it increases your heart rate; at higher doses, it induces low blood pressure and a slowed heart rate.

At smaller doses, marijuana can make you feel euphoric, detached and relaxed. At larger doses, you risk a racing heart rate, anxiety, paranoia, confusion, panic and even hallucinations.

One of the biggest challenges marijuana users face is not knowing how much THC they’re taking in as it varies widely from plant to plant, or even on different parts of the plant. Cannabis sold in the US can be highly potent.

Synthetic Cannabis (Spice)

Synthetic cannabis, known as “Spice,” contains a similar THC that is as much as 600 times more potent than traditional THC. Because Spice may not show up in standard urine drug screens, it’s often called a “legal” high and cannabis of choice, particularly among younger users.

Using Spice significantly compounds the risks associated with using marijuana. Pregnant women who have used Spice have experienced health emergencies including heart palpitations and an abnormally fast heart rate—even seizures.

Risking Preterm Birth?

If you’re using Spice and have these health complications, your symptoms can easily look like a dangerous form of high blood pressure in pregnancy called pre-eclampsia or eclampsia, which also have the side effects of seizures, say the obstetricians at the American College of Obstetricians and Gynecologists.

How Cannabis Affects Baby

Research shows cannabis can cross both the placenta and the blood-brain barrier, although most of this evidence comes from research in animals as it’s nearly impossible to do this type of research in pregnant women. In animals, offspring exposed to cannabis showed long-term and negative emotional, thinking and behavioral problems.

When it comes to pregnancy, experts think THC may change certain receptors in baby’s brain leading to problems with attention, memory and problem solving. Alarmingly, increasing evidence has shown that both natural and synthetic THC are harmful to a developing embryo as early as 2 weeks after conception—and that THC can affect your baby’s brain long before you skip a period or get those first symptoms that alert you to the fact that you’re pregnant.

When a baby is exposed to THC exposure in pregnancy weeks 1-4, the risk is increased for a rare and dangerous birth defect called anencephaly where a baby is born without parts of his or her brain and skull. Some research shows the risk of this birth defect—while rare—is nearly double among pregnant women who use marijuana. Sadly, almost all babies born with anencephaly die shortly after birth.

Consequences for Baby

When researchers followed infants who were exposed to marijuana during pregnancy, they linked the effects of that to lower birth weight, decreased height, early birth and increased risk for preterm labor. Mothers who used marijuana had more difficult and rapid labor, and often the baby was exposed to meconium while in the womb, raising baby’s risks for breathing problems at birth.

As these babies go through their toddler and early childhood years, researchers have documented both learning and behavior problems related to impaired mental development, hyperactivity, inattention and impulsivity. One study in particular demonstrated that first trimester exposure to marijuana resulted in problems with reading, spelling and overall educational scores at age 10. The same problems were also linked to second trimester exposure to marijuana.

Quit Marijuana for You & Your Baby

If you’re using marijuana now and aren’t doing anything to prevent pregnancy, or are actively trying to conceive a pregnancy, it’s important that you stop using cannabis for your health and your baby’s short and long-term health and development. Know that what drug use healthcare providers are required to report by law vary from state to state, with some states having mandatory reporting of cannabis use.

Breastfeeding & Marijuana

THC can accumulate in your breastmilk in high enough concentrations that your baby will pass THC in his or her urine during the first 2 to 3 weeks after birth. Your baby may also show the effects of the marijuana, including being quiet and sleepy, having poor muscle tone and nursing ineffectively at your breast. Experts advise that if you’re going to use marijuana after baby’s birth that you should avoid breastfeeding altogether, which robs both you and baby of the many protective and developmental benefits of lactation.

Talk to your nurse about why you use marijuana—is it for a health- or medical-related reason? Ask about other options to manage any problems you’re trying to aid with marijuana.

Cheryl K. Roth, PhD, WHNP-BC, RNC-OB, RNFA, is a nurse practitioner at HonorHealth Scottsdale Shea Medical Center in Scottsdale, AZ.
Lori A. Satran, RN, MS-L, IBCLCE, is clinical director of couplet care at HonorHealth Scottsdale Shea Medical Center in Scottsdale, AZ.
Shauna M. Smith, RN, is a doctoral nursing student at Arizona State University in Scottsdale, AZ.