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®.

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

Unlikely. Based on current research, 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?

Some studies have suggested that taking acetaminophen daily or most days during the second half of 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 may be the reason for the development of asthma in the child, rather than a direct effect of the acetaminophen treatment itself. At this time, it is not known whether using acetaminophen regularly during pregnancy is associated with a small chance of asthma or wheezing in children.

There have also been studies that noted a possible association with mild developmental delay and hyperactivity (especially when used for 28 days or more). 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.

Overall, acetaminophen is considered by most health care providers to be the pain reliever of choice during pregnancy.

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

It is always best to use medication only as needed. Since acetaminophen (paracetamol) is also in many combination medications, carefully check the ingredients of any other medications that you take. You will need to add up the amount of acetaminophen in the medications to make sure you are not taking more than you should. You should ask your health care provider how much acetaminophen you should be taking.

It is important that you do not take more than the maximum recommended dose of 4 grams (4000mg) in one day. Taking too much acetaminophen may 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. So, it is important that you not take more than the recommended amount.

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

Women who have had a liver injury should talk to their health care provider before taking acetaminophen (paracetamol) or other pain medication.

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

The amount of acetaminophen (paracetamol) that enters the breast milk is very small and less than the dose usually given to infants. Be sure to talk to your health care provider about all your choices for breastfeeding.

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

There is no evidence to suggest that a man’s taking acetaminophen (paracetamol) would affect his 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

References Available By Request.