In every pregnancy, a woman starts out with a 3-5% chance of having a baby with a birth defect. This is called her background risk. This sheet talks about whether exposure to acetaminophen (also known as paracetamol) may increase the risk for birth defects over that background risk. This information should not take the place of medical care and advice from your health care provider.

What is acetaminophen (paracetamol)?

Acetaminophen (paracetamol) is a medication used to treat fever and mild to moderate pain. Acetaminophen is available alone and in combination with other medications to treat symptoms of colds, flu, headache and osteoarthritis. You can buy acetaminophen in different forms, including liquids, tablets, capsules, and suppositories. A common brand name is Tylenol®.

I take acetaminophen (paracetamol). Can it make it harder for me to get pregnant?

Studies have not been done to see if acetaminophen could make it harder for a woman to get pregnant.

Can taking acetaminophen (paracetamol) during pregnancy cause miscarriage or birth defects?

Based on the studies, taking acetaminophen at the recommended doses is unlikely to increase the chance for pregnancy loss or birth defects.

Are there any other concerns related to taking acetaminophen (paracetamol) during pregnancy?

Acetaminophen is considered by most healthcare providers to be the pain reliever of choice during pregnancy. Aspirin and nonsteroidal anti-Inflammatory drugs (e.g. ibuprofen or naproxen) should not be used in pregnancy.

Some studies have suggested that taking acetaminophen daily or most days during the second half of the pregnancy could slightly increase the chance of wheezing or asthma in children. However, the illness the mother has, or other reasons why the mother needs to use the acetaminophen during her pregnancy, may be the reason for the development of asthma in the child, and not the acetaminophen itself.

There have also been studies that noted a possible association with mild developmental delay (including language delay) and hyperactivity. This association was stronger when the medication was used for 28 days or more during pregnancy. However, another study compared mother’s reported use of acetaminophen during pregnancy and then evaluated their children at four years of age and did not find an increased chance for harmful effects on these children’s I.Q., learning, or development. It is not yet clear if there is a direct relationship with acetaminophen, or if the findings were related to the reasons the mother took the medication, such as cold or fever, or a chance finding.

How much acetaminophen (paracetamol) is safe to take while I am pregnant?

It is best to use medication only as needed at the lowest effective dose. Your healthcare providers may have a recommendation about how much they want you to take. The maximum recommended dose of acetaminophen is 4000 mg in one day.

Taking too much acetaminophen (paracetamol) can cause liver damage, kidney damage, and anemia (low iron in the blood) in a pregnant woman. It has also been seen to cause the same problems in the baby.

Acetaminophen (paracetamol) is also in many combination medications. Carefully check the ingredients of any other medications that you take, to see if they also have acetaminophen. You will need to add up the amount of acetaminophen in the medications to make sure you are not taking more than 4000 mg in one day.

Is there anyone who should avoid taking acetaminophen (paracetamol)?

Women who have had a liver injury or liver disease should talk to their healthcare providers before taking acetaminophen (paracetamol) or other pain medication.

Is it safe for me to take acetaminophen (paracetamol) while I am breastfeeding?

Yes. The amount of acetaminophen (paracetamol) that enters the breast milk results in an infant exposure that is no more than about 4% of the dose usually given to infants (So much less than would be given directly to an infant, when needed). Be sure to talk to your health care provider about your breastfeeding questions.

Is it safe for the father of the baby to take acetaminophen (paracetamol)?

There is no evidence to suggest that acetaminophen (paracetamol) would affect a man’s ability to conceive or increase risk to a pregnancy. In general, exposures that fathers have are unlikely to increase risks to a pregnancy. For more information, please see the MotherToBaby fact sheet Paternal Exposures and Pregnancy at

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