As 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.
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.