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Is mesalamine safe during pregnancy?

Answered by MotherToBaby’s teratology specialists, quoted in full — including the questions most pages skip, like whether a father’s exposure matters.

By the pharmaranks editorial teamReviewed against the MotherToBaby fact sheet for mesalamine (OTIS, published via the NIH) sourcesUpdated Jul 21, 2026How we research

The questions people actually ask about mesalamine in pregnancy

Answered by MotherToBaby, the fact sheets written by the Organization of Teratology Information Specialists and published through the NIH. Quoted in full — we do not condense them.

I take mesalamine. Can it make it harder for me to get pregnant?

It is not known if mesalamine can make it harder to get pregnant.

Does taking mesalamine increase the chance of miscarriage?

Miscarriage is common and can occur in any pregnancy for many different reasons. One study of 146 people who used mesalamine in the first trimester did not find a higher chance of miscarriage.

Does taking mesalamine increase the chance of birth defects?

Every pregnancy starts out with a 3-5% chance of having a birth defect. This is called the background risk. Use of mesalamine in pregnancy is considered unlikely to significantly increase the chance of birth defects. There have been several studies looking at pregnancies exposed to both oral and rectal mesalamine in the first trimester that have found no increased chance of birth defects.

One study reviewed medical records of over 2,000 infants who were reportedly exposed to mesalamine at some time during the first trimester of pregnancy. This study found a slightly higher chance of heart defects. Many of the people in this study had also used other medications. This makes it hard to know if mesalamine, a combination of medications, the underlying disease, or other factors contributed to the reported slightly higher rate of heart defects.

Does taking mesalamine in pregnancy increase the chance of other pregnancy-related problems?

Mesalamine is not expected to increase the chance of pregnancy-related problems, such as preterm delivery (birth before week 37) or low birth weight (weighing less than 5 pounds, 8 ounces [2500 grams] at birth). There have been questions about a higher chance for preterm delivery and stillbirth from earlier reports. However, more recent data has not suggested an increased chance for these complications.

Does taking mesalamine in pregnancy affect future behavior or learning for the child?

Studies have not been done to see if mesalamine can increase the chance of behavior or learning issues for the child.

If a male takes mesalamine, could it affect fertility or increase the chance of birth defects?

There have been some reports of males who had lower sperm count while taking mesalamine. This could affect male fertility (ability to get partner pregnant). Sperm counts returned to usual after stopping the medication. There are no studies looking at possible risks to a pregnancy when the father or sperm donor takes mesalamine. In general, exposures that fathers or sperm donors have are unlikely to increase risks to a pregnancy. For more information, please see the MotherToBaby fact sheet on Paternal Exposures at https://mothertobaby.org/fact-sheets/paternal-exposures-pregnancy/ .

Quoted from MotherToBaby Fact Sheets — Mesalamine, published February 2024. MotherToBaby states its fact sheets should not take the place of medical care and advice from your healthcare providers.

Breastfeeding is a separate question — what LactMed says about mesalamine

This is general reference information, not medical advice. Whether to take any medication in pregnancy is a decision for you and your prescriber; do not start or stop a drug on your own, because an untreated condition can also carry risk.