Substance Use in Pregnancy: What to Tell Patients

Substance Use in PregnancyAs an OB/GYN physician with a special interest in opioid use disorders during pregnancy, I see many women of childbearing age who are struggling with a substance use disorder. Some of these women are contemplating pregnancy, while others are already pregnant. I often collaborate with psychiatrists when treating these women, and I enjoy sharing knowledge about the risks of substances and about treatment approaches.

In this article, I’ll start by briefly outlining what the research tells us about the risks of substance use to the fetus. The more informed you are about these risks, the more persuasive and helpful you can be to patients. I’ll then move on to discussing how, as an OB/GYN, I approach the evaluation and treatment of these patients, emphasizing issues of interest to clinicians.

Substance use during pregnancy is common. A national 2014 survey from the Substance Abuse and Mental Health Services Administration indicates that during pregnancy, up to 15% of women smoke cigarettes, 10% consume alcohol, and 5% use an illicit substance. This is data from community samples, and it’s likely that substance use is higher in pregnant women who present for psychiatric treatment.

Before going through each of the main substances of abuse, you should know that in most cases our knowledge of risk is very limited. For obvious ethical reasons, there are no human studies randomizing pregnant women to substance use vs control, and therefore we must rely on retrospective studies and animal research. In some cases, we have solid evidence of harm (such as the association of high alcohol intake with fetal alcohol syndrome), but for the most part we have no good evidence of either harm or safety. In the absence of evidence, a commonsense approach should rule —namely that exposing the developing fetus to potentially harmful drugs should be avoided if possible. This argument resonates with most patients.


Alcohol is an established teratogen, and it is associated with a condition called fetal alcohol syndrome (FAS)—a disorder that presents with growth deficiency, neurobehavioral disorders, and a specific pattern of facial abnormalities. In addition, abnormalities of the fetal heart, kidneys, ears, eyes, and skeleton are also associated with alcohol use in pregnancy.

Patients often ask if consumption of small amounts of alcohol causes FAS; they may also wonder if it’s safe for them to engage in moderate drinking later in pregnancy, after the major organs of the fetus have developed. I tell patients that since there are no studies of even small amounts of alcohol use in pregnancy, no amount of alcohol can be considered safe. In addition, while alcohol consumption is mostly related to birth defects in the first trimester, there is ongoing brain development throughout pregnancy, meaning that there’s no “safe” trimester in which to drink (Mamluk L et al, BMJ Open 2017;7(7):e015410).

Bottom line: Particularly for the fetal brain, no amount of alcohol in pregnancy has been identified as safe for fetal development. Therefore, I recommend that women not drink any alcohol at all during pregnancy. If your patient consumed alcohol prior to knowing that she was pregnant, she should be encouraged to discuss this with an OB provider, who will ask about the amount and timing of the use to determine possible risks. An ultrasound might be recommended to evaluate fetal growth and development. In many cases, if a patient has consumed only a small amount of alcohol in the early stages of the pregnancy, you can reassure her that the risks are low.


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Tobacco use during pregnancy has been associated with many potential problems, including an increased risk of miscarriage, poor fetal growth, premature birth, and stillbirth. In addition, babies born to smokers are at a higher risk of having colic and experiencing sudden infant death syndrome (SIDS) (Rogers JM, Reprod Toxicol 2009;28(2):152–160). They are also at an increased risk of childhood obesity and asthma. Quitting smoking during pregnancy will reduce these risks, and nicotine replacement products (such as nicotine gum or patches) are considered safe in pregnancy. For patients who are unable to quit, simply cutting down on daily smoking to half a pack per day or less might improve the baby’s growth.

Women sometimes ask me whether ecigarettes and vaping are less risky forms of tobacco use in pregnancy. At this time, we have no evidence to suggest that using these alternative products will pose a lower risk to mothers and babies than conventional cigarette smoking. These products contain nicotine, flavoring, and propellants that might not be safe in pregnancy. The reality is that we have absolutely no information on the effects of e-cigarettes or vaping, so we cannot with certainty say they are more or less safe than conventional cigarettes.

Bottom line: Tobacco use in pregnancy is associated with risks for pregnancy and for the long-term health of children. We do not know if e-cigarettes or vaping are a safer or riskier option in pregnancy, so they should be avoided. If women can cut down on their tobacco use or quit completely through FDA-approved nicotine substitutes, this provides the best chance for a healthy pregnancy. Smoking cessation even after pregnancy has begun might still provide a significant benefit.


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:

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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