Naltrexone and Pregnancy: What We Know About Safety

Finding out you’re pregnant can raise immediate questions about medications you’re already taking. If you take naltrexone to help reduce or stop drinking, you may be wondering whether you need to stop taking it, whether previous exposure could have affected your pregnancy, or whether naltrexone can be used during pregnancy at all.

Unfortunately, there isn’t a simple yes-or-no answer. Research on naltrexone use during pregnancy is limited, particularly among people taking it for alcohol use disorder. What we do have is somewhat reassuring, but not strong enough to establish that the medication is safe during pregnancy.

Here’s what the research tells us so far.

Is Naltrexone Safe During Pregnancy?

We don’t currently have enough evidence to say that naltrexone is safe during pregnancy. There have been no large, well-controlled studies establishing its safety in pregnant people, and much of the human research we do have comes from people taking naltrexone for opioid use disorder rather than AUD.

That doesn’t mean naltrexone is known to be harmful during pregnancy. So far, the limited human evidence has not identified a clear pattern of major adverse outcomes associated with naltrexone exposure. But the studies are too small and limited to rule out potential risks.

For someone with AUD, that uncertainty has to be considered alongside something we know much more about: alcohol exposure during pregnancy can harm a developing fetus. A 2024 review of medications for AUD during pregnancy concluded that naltrexone could be considered in some cases, particularly when psychosocial treatments have not been enough. However, the authors also emphasized that much more research is needed.

In other words, whether to use naltrexone during pregnancy is an individualized risk-benefit decision. If you’re already taking naltrexone when you find out you’re pregnant, don’t make a medication change based on something you read online. Contact your prescriber and prenatal clinician so they can help you decide what makes sense for your situation.

What Does “Pregnancy Category C” Mean for Naltrexone?

You may still see naltrexone described online as a “Category C” medication. This comes from an older FDA system that classified medications using the letters A, B, C, D, and X.

Under that system, Category C did not mean that a medication was known to cause birth defects or other pregnancy complications. It generally meant that animal studies had shown potential adverse effects, there were not adequate studies in pregnant humans, and the potential benefits of treatment might still justify use in some circumstances.

The FDA began replacing these letter categories in 2015 with the Pregnancy and Lactation Labeling Rule. Instead of assigning a single letter, the newer system requires prescription drug labeling to provide more detailed information about known risks, available evidence, and clinical considerations.

You may still encounter the old Category C designation on some naltrexone labels and medical websites. But the letter alone doesn’t tell you whether naltrexone is appropriate during pregnancy. The more useful question is what the available human evidence actually shows.

What Do Studies of Naltrexone During Pregnancy Show?

Research on naltrexone during pregnancy is limited, especially among people taking it for alcohol use disorder.

A 2024 scoping review examined the available evidence on medications used to treat AUD during pregnancy. Although the authors identified 21 naltrexone-related studies, only eight were clinical studies involving naltrexone exposure during pregnancy. All eight involved people with opioid use disorder rather than AUD.

Overall, those studies did not identify a clear pattern of serious pregnancy or newborn complications associated with naltrexone. But the evidence varied in quality, and research involving people with OUD cannot necessarily tell us what to expect when naltrexone is used for AUD.

A 2024 prospective case series provides some alcohol-specific evidence, although the study was very small. Researchers followed seven pregnant people taking naltrexone, three of whom had AUD and four of whom had OUD. There were no reported fetal anomalies, and there was one preterm delivery. Two participants with AUD returned to alcohol use during the study.

These results are reassuring, but a study of seven pregnancies cannot establish that naltrexone is safe during pregnancy or rule out uncommon risks. For now, the most accurate conclusion is that the available human evidence has not revealed a clear signal of major harm, but there is far too little of it to draw firm conclusions.

Alcohol Use During Pregnancy Carries Known Risks

One reason decisions about naltrexone during pregnancy can be complicated is that avoiding medication does not necessarily mean avoiding risk. For someone struggling to stop drinking, clinicians also have to consider the well-established risks of prenatal alcohol exposure.

The CDC states that there is no known safe amount of alcohol use during pregnancy, no safe time to drink during pregnancy, and no type of alcohol that is considered safe. Alcohol use during pregnancy is associated with miscarriage, preterm birth, stillbirth, and fetal alcohol spectrum disorders (FASDs).

Stopping alcohol use at any point during pregnancy can help. But if you drink heavily or regularly, particularly if you have experienced withdrawal symptoms before, it’s important to get medical guidance rather than trying to manage the situation entirely on your own. Alcohol withdrawal can be dangerous, and pregnancy makes appropriate medical care especially important.

This is why the question of naltrexone during pregnancy isn’t simply “medication risk versus no risk.” Depending on the situation, a clinician may need to weigh the uncertain risks of medication exposure against the known risks of continued alcohol exposure, along with the risks and benefits of other treatment options.

What If You Become Pregnant While Taking Naltrexone?

If you find out you’re pregnant while taking naltrexone, contact the clinician who prescribed it and your prenatal clinician. Don’t stop or change the medication on your own based solely on something you read online.

Be prepared to tell your clinicians why you take naltrexone, how much and how often you have been drinking, when you last drank, and what other medications or substances you use. This information can help them weigh the potential risks of continuing naltrexone against the risks of changing treatment.

There is some precedent for this kind of individualized decision-making. Guidance from the American College of Obstetricians and Gynecologists states that people who become pregnant while taking naltrexone for opioid use disorder should discuss the decision to continue treatment with their healthcare provider. That conversation should consider the limited safety data as well as the potential risk of relapse if naltrexone is discontinued.

That guidance is specifically about opioid use disorder, not AUD. But the broader principle applies here: pregnancy does not automatically make this a simple stop-or-continue decision. Your clinician can help you weigh the risks and benefits based on your individual situation.

How Is Alcohol Use Disorder Treated During Pregnancy?

Behavioral treatments are generally an important part of treating alcohol use disorder during pregnancy. Depending on your needs, treatment might include brief interventions, motivational interviewing, cognitive behavioral therapy, peer support, and ongoing care from your prenatal or behavioral health team.

Medication is more complicated because there is relatively little pregnancy-specific evidence for medications used to treat AUD. A 2024 review of the evidence found insufficient pregnancy safety data for the medications commonly used for AUD, including naltrexone. The authors nevertheless concluded that naltrexone could be considered in some circumstances when psychosocial treatment has not been enough, given the established risks of continued alcohol exposure during pregnancy.

If you drink heavily or think you could experience withdrawal when you stop, tell your healthcare provider. Alcohol withdrawal can require medical treatment, and trying to manage significant withdrawal without medical supervision can be dangerous.

If you are planning a pregnancy rather than currently pregnant, consider discussing naltrexone with your prescriber before you start trying to conceive. That gives you time to review your medication, drinking patterns, and other treatment options and make a plan in advance.

Can You Use Sunnyside Med During Pregnancy?

Sunnyside Med does not prescribe naltrexone during pregnancy or while breastfeeding. If you are currently taking naltrexone through Sunnyside Med and become pregnant, contact your care team so they can help you determine the appropriate next steps.

During pregnancy, your prenatal clinician should be your primary resource for decisions about alcohol use and treatment. This is especially important if you are drinking regularly, have had withdrawal symptoms in the past, or are concerned that stopping alcohol could cause withdrawal.

If you are planning to become pregnant, you can also talk with your clinician ahead of time about how naltrexone fits into that plan. After pregnancy and breastfeeding, if you are interested in medication to help you drink less or stop drinking, a licensed Sunnyside Med clinician can assess whether naltrexone is appropriate for you.

Naltrexone is a prescription medication. This content is educational and should not be taken as medical advice. A licensed clinician reviews every Sunnyside Med application.