Is Pentasa safe during pregnancy? A guide for expectant mothers with IBD

October 8, 2025 •

4 min read

Studies consistently show that active Inflammatory Bowel Disease (IBD) poses a greater risk to a pregnant woman and her baby than most IBD medications, including Pentasa. This makes informed treatment decisions, like understanding if Pentasa is safe during pregnancy, a crucial part of prenatal care.

Quick Summary

Managing inflammatory bowel disease with Pentasa during pregnancy is generally considered safe and is often safer than leaving the condition untreated. Consult your doctor for personalized guidance.

Key Points

Active IBD is the Greatest Risk: The most significant risk to a healthy pregnancy for women with IBD is an active disease flare-up, not typically the medication used to treat it.
Pentasa is a Low-Risk Treatment: Medical consensus and a Pregnancy Category B classification indicate that Pentasa (mesalamine) is generally considered safe for use during pregnancy.
No Increased Risk of Birth Defects: Studies have found no reliable evidence that mesalamine increases the overall rate of major congenital malformations in infants.
Disease Control is Paramount: Healthcare providers stress the importance of maintaining remission throughout pregnancy, as an IBD flare can lead to complications like preterm birth and low birth weight.
Breastfeeding Safety: Pentasa is generally safe during breastfeeding, but infants should be monitored for diarrhea, a rare but reported side effect.
Not All Mesalamine is Equal: It is important to know that certain older mesalamine formulations (like Asacol HD) have inactive ingredients that are avoided during pregnancy, and alternatives like Pentasa or Delzicol are safer choices.

The Importance of Managing IBD During Pregnancy

For expectant mothers with Inflammatory Bowel Disease (IBD), the question of medication safety is paramount. Medical guidelines and studies confirm that keeping IBD in remission is the most critical factor for a healthy pregnancy and a healthy baby. In fact, the risks associated with an IBD flare-up during pregnancy—which can include preterm delivery, low birth weight, and even stillbirth—are often significantly higher than the risks posed by mesalamine, the active ingredient in Pentasa. Therefore, the decision is not typically about avoiding medication but rather about choosing the safest and most effective option to manage the disease throughout gestation.

What is Pentasa?

Pentasa is a brand name for the drug mesalamine, also known as 5-aminosalicylic acid (5-ASA). It is used to treat mild to moderate ulcerative colitis (UC) and, in some cases, Crohn's disease, both of which are forms of IBD. Mesalamine works as an anti-inflammatory agent, primarily in the intestinal lining, to reduce swelling and irritation. The capsules are designed with an extended-release formula to distribute the medication throughout the entire small and large intestine, ensuring the drug reaches the affected areas.

Medical Consensus on Pentasa in Pregnancy

Professional medical organizations, such as the American Gastroenterological Association (AGA) and the Crohn's & Colitis Foundation, support the continued use of mesalamine during pregnancy.

Here’s what medical evidence suggests about its safety:

FDA Pregnancy Category B: Many mesalamine formulations, including Pentasa, were classified as Pregnancy Category B, indicating that animal studies did not show harm to the fetus and there are no well-controlled studies in pregnant women. While the FDA has replaced this categorical system, the body of research still supports this low-risk assessment.
No Increased Risk of Major Birth Defects: Several studies, including a prospective controlled cohort study by the Motherisk Program, found no increase in major malformations among infants exposed to mesalamine during the first trimester. This suggests that it does not pose a significant teratogenic risk.
Risks Often Confounded by Disease Activity: Older studies that reported a slight increase in preterm birth or lower birth weight among mesalamine-exposed infants often failed to account for disease activity. It is now understood that active IBD is the primary driver of these complications, not the medication itself.

Comparing Mesalamine Formulations in Pregnancy

While Pentasa is generally considered safe, not all mesalamine formulations have the same safety profile. Some oral tablets contain inactive ingredients that have raised concerns based on animal studies. It is crucial to be aware of these differences and discuss all medications with your doctor.


Feature	Pentasa (Mesalamine)	Asacol HD (Mesalamine)	Delzicol (Mesalamine)
Formulation	Extended-release capsules or rectal	Delayed-release tablets	Delayed-release capsules
Active Ingredient	Mesalamine (5-ASA)	Mesalamine (5-ASA)	Mesalamine (5-ASA)
Inactive Ingredients	Talc, povidone, etc.	Contains dibutyl phthalate (DBP) in the coating	Does not contain dibutyl phthalate (DBP)
Safety in Pregnancy	Generally Considered Safe (Category B)	Avoid if Possible (Category C); DBP linked to animal malformations	Generally Considered Safe (Category B); DBP-free replacement for Asacol
Recommendation	Safe to continue if effective	Discuss switching to an alternative with your doctor	Safe to use during pregnancy

Important Considerations and Safety Precautions

Before, during, and after pregnancy, your gastroenterologist and obstetrician should work together to create a personalized treatment plan. Here are some key considerations:

Preconception Counseling: Ideally, any woman with IBD who plans to conceive should consult with her healthcare team to ensure her disease is in remission before she becomes pregnant.
Continuous Treatment: Do not stop taking Pentasa without first discussing it with your doctor, even if your symptoms seem to disappear. Stopping treatment can lead to a flare-up, which is more harmful to the pregnancy.
Dosage and Frequency: Continue your prescribed dosage throughout pregnancy unless your doctor advises otherwise. A consistent dosing schedule is important for maintaining disease control.
Nutritional Support: Ensure you are taking prenatal vitamins, including a folic acid supplement. This is particularly important for patients on sulfasalazine, another 5-ASA, but good practice for all pregnant women with IBD.

Pentasa and Breastfeeding

For nursing mothers, Pentasa (mesalamine) is generally considered safe, but monitoring is necessary.

Excretion into Breast Milk: Small amounts of mesalamine can be excreted into breast milk. The concentration is low, but some infants may react.
Monitor for Diarrhea: A small number of breastfed infants have been reported to develop diarrhea while their mothers were taking mesalamine. If this occurs, it is recommended to stop breastfeeding and consult your healthcare provider.
Benefits Outweigh Risks: For most mothers and infants, the benefit of continued disease control for the mother is believed to outweigh the low risk of infant side effects. The American Gastroenterological Association guidelines support breastfeeding while monitoring for diarrhea.

Conclusion

For pregnant women with IBD, keeping the disease in remission is the single most important factor for a successful pregnancy. While concerns about medication safety are understandable, decades of clinical experience and multiple studies show that Pentasa, an aminosalicylate, is a low-risk option during pregnancy and lactation. The overwhelming medical consensus is that the risks of an uncontrolled IBD flare-up far outweigh the risks associated with continued mesalamine treatment. Any adjustments to your medication plan should always be made in close consultation with your gastroenterologist and obstetrician to ensure the best possible outcome for both you and your baby.

For more comprehensive information on inflammatory bowel disease and pregnancy, expectant mothers can consult resources from the Crohn's & Colitis Foundation.

Frequently Asked Questions

Pentasa (mesalamine) was formerly categorized as FDA Pregnancy Category B. This designation indicated that animal studies had shown no risk to the fetus, but there were no adequate, controlled studies in humans. While this system is no longer used, Pentasa is still considered a low-risk option for treating IBD during pregnancy.

No, you should not stop taking Pentasa without consulting your doctor first. An abrupt cessation of medication can trigger an IBD flare-up, which poses a greater risk to the pregnancy than continuing the medication.

Untreated, active IBD during pregnancy carries several risks, including increased chances of miscarriage, preterm delivery, low birth weight, and stillbirth. Maintaining remission is crucial for a healthy pregnancy outcome.

Some reports have shown that mesalamine can cause a lower sperm count in males, which could affect fertility. This effect is typically reversible upon stopping the medication. If you are a male on Pentasa planning to conceive, you should discuss this with your doctor.

No. While most are considered safe (like Pentasa and Delzicol), some older formulations like Asacol HD contain dibutyl phthalate (DBP) in the coating, an inactive ingredient that has shown negative effects in animal studies. Your doctor may recommend switching to an alternative if you are taking a DBP-containing product.

If your baby develops persistent diarrhea, you should contact your doctor immediately. Although small amounts of mesalamine pass into breast milk, diarrhea is a known, though rare, potential side effect.

Yes, it is recommended that all pregnant women take a folic acid supplement. While Pentasa does not interfere with folic acid absorption like sulfasalazine does, a high-dose supplement (such as 2mg or 5mg daily) is still advised for women with IBD.

No, reliable human studies have not demonstrated a link between mesalamine and an increased risk of birth defects. The risk of congenital malformations in infants exposed to mesalamine is comparable to the general population.