Certain prescription and over-the-counter pain relievers, as well as some antibiotics and other prescription drugs, may not be safe to take while pregnant. Talk with your doctor to weigh the benefits and risks.

With rules about pregnancy medications constantly changing, it can feel overwhelming to know what to do when you’re feeling sick.

It usually comes down to weighing the benefits for a mother with a health condition — even one as simple as a headache — against potential risks to her developing baby.

The problem: Scientists can’t ethically perform drug testing on a pregnant woman. It’s not accurate to say a medication is 100 percent safe for a pregnant woman (simply because it’s never been studied or tested).

In the past, medications were assigned to five letter categories based on their level of risk. Category A was the safest category of drugs to take. Drugs in Category X were never to be used during pregnancy.

In 2015, the Food and Drug Administration (FDA) started to implement a new labeling system for drugs.

Below is a sampling of a few of the drugs that we know pregnant women should avoid.

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Antibiotics are often linked to adverse reactions in pregnant women.

Chloramphenicol is an antibiotic that’s usually given as an injection. This drug can cause serious blood disorders and gray baby syndrome.

Ciprofloxacin (Cipro) and levofloxacin are also types of antibiotics. These drugs could cause problems with the baby’s muscle and skeletal growth as well as joint pain and potential nerve damage in the mother.

Ciprofloxacin and levofloxacin are both fluoroquinolone antibiotics.

Fluoroquinolones can increase the risk of aortic tears or ruptures. This can result in life-threatening bleeding. People with a history of aneurysms or certain heart diseases may be at an increased risk of side effects.

Fluoroquinolones may also increase the chances of having a miscarriage, according to a 2017 study.

Primaquine is a drug that’s used to treat malaria. There isn’t a lot of data on humans who’ve taken this drug during pregnancy, but animal studies suggest it’s harmful to developing fetuses. It can damage blood cells in a fetus.

Sulfonamides are a group of antibiotic medications. They’re also known as sulfa drugs.

The majority of these types of drugs are used to kill germs and treat bacterial infections. They can cause jaundice in newborns. Sulfonamides may also increase the chances of having a miscarriage.

Trimethoprim (Primsol) is a type of antibiotic. When taken during pregnancy, this drug can cause neural tube defects. These defects affect brain development in a developing baby.

Codeine is a prescription drug used to relieve pain. In some states, codeine can be purchased without a prescription as a cough medicine. The drug has the potential to become habit-forming. It can lead to withdrawal symptoms in newborns.

High doses of this OTC pain reliever can cause many serious problems, including:

  • miscarriage
  • delayed onset of labor
  • premature closing of the fetal ductus arteriosus, an important artery
  • jaundice
  • hemorrhaging for both mother and baby
  • necrotizing enterocolitis, or damage to the lining of the intestines
  • oligohydramnios, or low levels of amniotic fluid
  • fetal kernicterus, a type of brain damage
  • abnormal vitamin K levels

Most experts agree that ibuprofen is probably safe to use in small to moderate doses in early pregnancy.

It’s especially important to avoid ibuprofen during the third trimester of pregnancy, however. During this stage of pregnancy, ibuprofen is more likely to cause heart defects in a developing baby.

Warfarin (Coumadin) is a blood thinner that’s used to treat blood clots as well as prevent them. It can cause birth defects.

It should be avoided during pregnancy unless the risk of a blood clot is more dangerous than the risk of harm to the baby.

Clonazepam (Klonopin) is used to prevent seizures and panic disorders. It’s sometimes prescribed to treat anxiety attacks or panic attacks.

Taking clonazepam during pregnancy can lead to withdrawal symptoms in newborns.

Lorazepam (Ativan) is a common medication used for anxiety or other mental health disorders. It can cause birth defects or life-threatening withdrawal symptoms in a baby after birth.

Drug labels listing pregnancy letter categories will be completely phased out by June 2020.

One important note about the new labeling system is that it doesn’t affect over-the-counter (OTC) medications at all. It’s only used for prescription drugs.


The first subsection of the new label is titled “Pregnancy.”

This subsection includes relevant data about the drug, information on risks, and information on how the drug may affect labor or delivery. If a pregnancy exposure registry exists for the drug, information on the registry (and its findings) will also be included in this subsection.

Pregnancy exposure registries are studies that collect information about different medications and their possible effects on pregnant women, breastfeeding women, and their babies. These registries aren’t conducted by the FDA.

Women who are interested in participating in a pregnancy exposure registry can volunteer, but participation isn’t required.


The second subsection of the new label is titled “Lactation.”

This part of the label includes information for women who are breastfeeding. Information such as the amount of the drug that will be present in breast milk and the drug’s potential effects on a breastfeeding infant is provided in this section. Relevant data is also included.

Females and males of reproductive potential

The third subsection of the new label is titled “Females and males of reproductive potential.”

This section includes information on whether women using the drug should undergo pregnancy testing or use specific methods of contraception. It also includes information about the drug’s effect on fertility.

If you’re not sure whether or not a medication is safe to take during pregnancy, ask your doctor. Also, ask about updated studies, as pregnancy drug labels can change with new research.

Chaunie Brusie, BSN, is a registered nurse in labor and delivery, critical care, and long-term care nursing. She lives in Michigan with her husband and four young children and is the author of “Tiny Blue Lines.”