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Pregnant? Nursing? Here’s What You Need to Know About Medication

January 17th, 2017

Congratulations! You’re pregnant (or thinking of becoming pregnant). Or you just had the baby and plan to breastfeed. All wonderful news. . . until you think about reaching for the medicine bottle. How do you know if that medication—whether prescription or over-the-counter—is safe for you and your baby?


It’s not easy.

The problem is that drug companies are not allowed to test investigational drugs on pregnant women – it’s simply not ethical. So the only information we have about the potential risks of medications during pregnancy or breastfeeding come from animal studies, post-marketing reports to the Food and Drug Administration (FDA) or pregnancy registries. The registries are, essentially, large databases that collect health-related information from women while they’re pregnant. You can view a list of registries by medical condition (cancer, epilepsy, autoimmune disease, HIV/AIDS or a transplant) or by the name of the drug or vaccine here.

You can also learn more about the drug’s possible effects during pregnancy by reading the drug label. All labels must have information about the use of the drug during pregnancy or while breastfeeding. Current pregnancy labeling uses five categories—A, B, C, D, and X.

Pregnancy category A.

This category is for drugs that have been tested in well-designed studies and show no risk to the baby throughout pregnancy. You can find a list of category A drugs here.

Pregnancy category B.

This category is for drugs for which animal studies show no risk to the fetus yet for which there are no well-designed, controlled studies in women. You can find a list of category B drugs here.

Pregnancy category C.

This category is for drugs in which animal studies show harm to the fetus and there are no well-designed studies in pregnant women, yet the benefits of the drug may be worth the risks.

Pregnancy category D.

This category is for drugs for which there is evidence of harm to the baby based on data from studies or real-life experiences, yet the potential benefits may still outweigh the risks (such as a drug needed in a life-threatening situation or serious disease for which safer drugs cannot be used or are ineffective).

Pregnancy category X.

This category is for drugs for which any studies (animal or human) or real-life experiences show harm to the fetus and the risk of the drug clearly outweighs any possible benefit (for instance, safer drugs or treatments are available.)

Drugs to Avoid During Pregnancy

When considering whether to take a medication during pregnancy, it’s important that you and your doctor consider your stage of pregnancy. Certain drugs are classified as “teratogens” because they cause changes in the development of the fetus early in the pregnancy, typically the first three months, but may be safe later in pregnancy. The most common birth defects include neural tube defects such as spina bifida; congenital heart problems; cleft lip or palate; and miscarriage or stillbirths. 1

“Adverse fetal defects” occur later in the pregnancy, and include neurological problems like attention deficit hyperactivity disorder (ADHD) and autism; metabolic abnormalities, such as an increased risk of diabetes; and congenital heart problems. The good news is that just 2 to 3 percent of all birth defects are related to medications. Nonetheless, it’s important to understand the risks associated with certain medications so you can have an informed discussion with your doctor.

Among the drugs associated with birth defects are: 2 3

·      The antibiotic D-penicillamine and tetracycline antibiotic

·      The hyperthyroidism medication methimazole (Tapazole)

·      The anti-anxiety medication diazepam (Valium)

·      Opioids

·      Alcohol

·      Certain high blood medications

·      Certain anti-seizure medications

·      Warfarin (Coumadin)

·      The acne medication isotretinoin (Accutane)

·      The bipolar medication lithium

·      The anti-ulcer medication misoprostol (Cytotec)

·      Certain antidepressants

Talking to Your Doctor or Midwife about Medication

Even if your medication appears safe, make sure you check with your doctor first. The same goes for stopping any medication when you learn you’re pregnant. You and your doctor also need to discuss the pros and cons of the medication you’re taking and the risks to you and your baby if you stop taking it versus the risks if you continue taking it. You should also check with your doctor or midwife before taking any over-the-counter medications, herbal remedies, and nutritional supplements.

When you talk to your doctor about medications during pregnancy or while breastfeeding, make sure you ask the following questions:

  • What does the evidence show about its use during pregnancy/breastfeeding?
  • Does the dose need to be changed?
  • What are the risks of not taking it?
  • Are safer options available?
  • Are there different complications or side effects I should be aware of?
  • Will the drug affect me during labor and delivery?
  • Is there any evidence of later complications, such as in the growth, development and maturation of the baby?
  • Are there ways to minimize the baby’s exposure to the drug through my breast milk?
  • Are there any signs I should watch for that suggest the drug might be affecting the baby while nursing?

Paying attention to everything you put in your body during pregnancy and breastfeeding will help you in your quest to have a healthy baby.



  1. Burkey BW, Holmes AP. Evaluating medication use in pregnancy and lactation: what every pharmacist should know. J Pediatr Pharmacol Ther. 2013;18(3):247-58. 
  2. Rai D, Lee BK, Dalman C, et al. Parental depression, maternal antidepressant use during pregnancy, and risk of autism spectrum disorders: population based case-control study. BMJ. 2013;19;346:f2059.  
  3. Yazdy MM, Mitchell AA, Tinker SC, et al. Periconceptional Use of Opioids and the Risk of Neural Tube Defects. Obstet Gynecol. 2013;122(4):838-844. 

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