The information provided below is for readers based in the United States of America. Readers outside of the United States of America should seek the information from local sources.


Due to a lack of safety information during pregnancy, dimethyl fumarate should only be used in pregnant or nursing women when the benefits to the mother outweigh the risks to the baby.

What is dimethyl fumarate?

Dimethyl fumarate is a disease-modifying prescription medication taken by mouth. 

What is dimethyl fumarate used to treat?

Dimethyl fumarate is used to treat relapsing multiple sclerosis. 

How does dimethyl fumarate work?

Dimethyl fumarate works by reducing inflammation in the body.  It is an anti-inflammatory drug that interacts with proteins in the body that respond to oxidative stress, increasing the antioxidant properties of cells.

If I am taking dimethyl fumarate, can it harm my baby?

It is unknown whether dimethyl fumarate crosses the human placenta to reach the developing baby. Evidence on the safety of dimethyl fumarate during pregnancy is limited. In animal studies, high dose dimethyl fumarate was associated with negative side effects in the developing baby including low birth weight, poor sexual development, and cancer.

If I am taking dimethyl fumarate and become pregnant, what should I do?

Women who are trying to become pregnant or discover they are pregnant should speak with their doctor before using dimethyl fumarate. Dimethyl fumarate should only be used during pregnancy if the maternal benefits outweigh the risks to the developing baby.

If I am taking dimethyl fumarate, can I safely breastfeed my baby?

It is unknown if dimethyl fumarate passes into the breast milk; however, it is estimated that breastfeeding infants will receive 3.5% of the mother’s dose of dimethyl fumarate. There is limited information available on the safety of nursing while on dimethyl fumarate. It is important to weigh the risks versus benefits of continuing or discontinuing breastfeeding while on this medication. Some guidance suggests avoiding breastfeeding for 4-5 hours after taking dimethyl fumarate to prevent infant exposure. Women who continue nursing while on dimethyl fumarate should monitor infants for signs of poor weight gain, stomach pain, diarrhea, and upset stomach.

If I am taking dimethyl fumarate, will it be more difficult to get pregnant?

Animal studies suggest that dimethyl fumarate can negatively affect both the male sperm and female ovulation.

If I am taking dimethyl fumarate, what should I know?

It is important to speak with your doctor to discuss the safety of dimethyl fumarate exposure during pregnancy or breastfeeding. Limited information is available on the safety of this medication while pregnant.

If I am taking any medication, what should I know?

This report provides a summary of available information about the use of dimethyl fumarate during pregnancy and breastfeeding. Content is from the product label unless otherwise indicated.

You may find Pregistry's expert reports about neurological disorders here,  reports about the individual medications used to treat neurological disorders here, and a report about multiple sclerosis here. Additional information can also be found in the resources below. 

For more information about dimethyl fumarate during and after pregnancy, contact http://www.womenshealth.gov/ (800-994-9662 [TDD: 888-220-5446]) or check the following link:

Tecfidera.com: Tecfidera Prescribing Information

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General information

It is very common for women to worry about having a miscarriage or giving birth to a child with a birth defect while they are pregnant. Many decisions that women make about their health during pregnancy are made with these concerns in mind.

For many women these concerns are very real. As many as 1 in 5 pregnancies end in a miscarriage, and 1 in 33 babies are born with a birth defect. These rates are considered the background population risk, which means they do not take into consideration anything about the health of the mom, the medications she is taking, or the family history of the mom or the baby’s dad. A number of different things can increase these risks, including taking certain medications during pregnancy.

It is known that most medications, including over-the-counter medications, taken during pregnancy do get passed on to the baby. Fortunately, most medicines are not harmful to the baby and can be safely taken during pregnancy. But there are some that are known to be harmful to a baby’s normal development and growth, especially when they are taken during certain times of the pregnancy. Because of this, it is important to talk with your doctor or midwife about any medications you are taking, ideally before you even try to get pregnant.

If a doctor other than the one caring for your pregnancy recommends that you start a new medicine while you are pregnant, it is important that you let them know you are pregnant.

If you do need to take a new medication while pregnant, it is important to discuss the possible risks the medicine may pose on your pregnancy with your doctor or midwife. They can help you understand the benefits and the risks of taking the medicine.

Ultimately, the decision to start, stop, or change medications during pregnancy is up to you to make, along with input from your doctor or midwife. If you do take medications during pregnancy, be sure to keep track of all the medications you are taking.