Substance Use in Pregnancy: What to Tell Patients


Marijuana is the illicit drug most commonly used during pregnancy, and the rate of use is likely to increase as more states legalize it. I commonly see women who have been prescribed medical marijuana products and are unsure what to do if they are planning to become or have already become pregnant. Because marijuana is a naturally occurring plantbased product, patients sometimes believe that recreational use of marijuana is “safer” than other illicit substances.

Tetrahydrocannabinol (THC) has been shown to cross the placenta, and it accumulates in tissues such as the brain and fat. Animal studies have identified brain developmental abnormalities with in-utero exposure, and recent human research also suggests that prenatal marijuana exposure can be associated with poor visual-motor coordination and decreased attention span (Volkow ND et al, JAMA 2017;317(2):129–130).

However, there are still no concrete data on long-term outcomes, including school performance for children exposed to cannabis products during pregnancy. Cannabis use has not been associated with poor fetal growth, increased risk of preterm delivery or stillbirth, or birth defects. I’m sometimes asked if ingesting edible cannabis products is safer than smoking marijuana. At this point, since we lack any studies examining this issue, the best answer is no.

Bottom line: Right now, there is limited evidence on the effects of using marijuana during pregnancy. The little data that we have suggest that there may be developmental issues in children with prenatal marijuana exposure, but we do not have information on longterm outcomes. Pending further studies, women on medical marijuana should seek alternative therapies, and pregnant women should avoid recreational marijuana use.


The risks of opioid use in pregnancy include poor fetal growth and premature delivery. In addition, patients with untreated opioid use disorder are at higher risk of additional complications, such as poor attendance in prenatal care, infectious diseases such as hepatitis C and HIV, and intimate partner violence and housing instability (Reddy UM et al, Obstet Gynecol 2017;130(1):10–28).

Abrupt cessation of chronic opioid use will result in significant withdrawal symptoms for patients, and withdrawal symptoms can also occur in infants who were exposed during pregnancy to chronic maternal opioid use. Infants have a 30%– 70% risk of neonatal abstinence syndrome (NAS), a type of newborn withdrawal that is readily treatable if identified, but can be severe and even life-threatening if not addressed. To diagnose and treat this condition, infants often require extended hospitalizations after delivery.

NAS may occur whether opioids are used as prescribed or illicitly. The recommended treatment for opioid use disorders in pregnancy is medication-assisted therapy using methadone or buprenorphine, and both can also cause NAS. Since attempts at abstinence are associated with a 90%–95% risk of relapse, the American College of Obstetrics and Gynecology (ACOG) strongly recommends that women treated with methadone or buprenorphine remain in treatment during pregnancy (See the ACOG statement on pregnant women and opioid use:

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It is important to note that, with situations such as kidney stones or appendectomy, short courses of opioids are often prescribed during pregnancy; such intermittent use of medically indicated opioids is considered an acceptable treatment. There is no clear evidence that this type of use is associated with a higher risk of neonatal withdrawal or other pregnancy complications. However, it is recommended that you use the lowest effective dose, and for the shortest amount of time.

Bottom line: If NAS is not identified and treated after birth, babies face potentially life-threatening withdrawal symptoms. However, when it is identified ahead of time, neonatal withdrawal is a manageable side effect of often life-saving treatment with methadone or buprenorphine. Encourage women who are in medication-assisted therapy to remain on their medication throughout the pregnancy, and tell patients to discuss possible treatment of their babies with their OB providers.


Although amphetamine-related medications can be safely used when medically indicated for ADHD and similar disorders in pregnancy, it is unclear if the misuse of these medications while pregnant poses risks for mother or baby. There is no evidence to suggest a clear association of medically prescribed amphetamine or methylphenidate with an increased risk of birth defects.

There are clearer risks associated with the use of recreational stimulants, however. Methamphetamine increases the risk of poor fetal growth as well as neonatal and childhood neurodevelopmental abnormalities. Cocaine use creates a risk of poor fetal growth, premature delivery, and premature detachment of the placenta (abruption), which might cause stillbirth. In addition, illicit use of cocaine/amphetamine is also associated with miscarriage, premature labor, impaired fetal growth, low birth weight, and neonatal withdrawal symptoms. Complications for the mother can include severe hypertension, which can result in stroke, and permanent disabilities (Wright TE et al, J Addict Med 2015;9(2):111–117).

Bottom line: Although stimulants are less well studied than other substances, prescribed amphetamine-related compounds have not been associated with pregnancy complications, and they may be continued as medically appropriate. However, tell your patients to avoid both illicit methamphetamine and cocaine use throughout their pregnancy.

Evaluation and treatment recommendations

Assessing substance use can be a delicate proposition in any clinical setting, but this is especially true when evaluating women of potentially childbearing age (defined by the CDC as ages 15–44). In addition to the usual sense of embarrassment or shame that many patients feel when admitting substance use, there may be potential legal ramifications. Depending on state law, providers may be encouraged or even mandated to report patients who disclose substance use in pregnancy. This adds to patients’ reluctance to divulge such information.

I have found the most success with prenatal patients by introducing substance use screening as a required and routine component of the first OB visit. I approach the subject in a non-judgmental way, and emphasize that substance use disorders are medical problems that we can help address. If I sense that a
patient is hiding a problem because of mandated reporting concerns, I will say, “I am concerned that you may be hesitant to share some things that you may be struggling with in your pregnancy. I am worried about substance use, as well as the possibility that I might not have all the information that I need to keep you healthy during pregnancy.”

ACOG suggests that you use a validated screening tool for women, and in my practice, I have found much success with the “4 Ps”: a set of questions that are highly sensitive for identifying a potential problem.

If my screening identifies a substance use problem, we then discuss the risks for the patient’s pregnancy and long-term health, and I offer her resources for substance use treatment. I will usually recommend attending a 12-step program. Some OB providers, including myself, do provide buprenorphine, but we refer all patients interested in methadone treatment to a federally supervised opioid treatment program.

CATR VERDICT: Substance use by a pregnant patient is risky to both the mother and unborn child. Help your patients understand the risks, and don’t hesitate to refer to an OB/GYN for further evaluation. 

Substance problems in pregnancyOBGYN referral due to substance use

Substance Use in Pregnancy: What to Tell Patients

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This article was published in print November/December 2017 in 5:8.


APA Reference
Wedel, C. (2019). Substance Use in Pregnancy: What to Tell Patients. Psych Central. Retrieved on April 3, 2020, from


Scientifically Reviewed
Last updated: 11 Jun 2019
Last reviewed: By John M. Grohol, Psy.D. on 11 Jun 2019
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