The use of common Crohn's and colitis (IBD) medications during pregnancy and while a baby is breastfeeding is a concern for many women. There are fears that these medications might harm the developing fetus or be passed to the child through breast milk. Research has shown that most IBD-related medications that are taken before and during pregnancy and after delivery, have no negative effect on the mother, fetus or newborn child. But, there are some cautions. So, let’s take a closer look at specific classes of medications that are used and how each affect the mother and baby.
The anti-inflammatory drugs mesalamine (Asacol, Rowasa, Pentasa, Salofalk) and sulfasalazine (Azulfidine, Salazopyrin) have a long history of being used to treat patients with Crohn's disease or ulcerative colitis. Neither mesalamine nor sulfasalazine has been found to increase the risk of adverse effects during pregnancy. Extremely small amounts of aminosalicylates have been found in breast milk, but these trace levels do not pose a danger to a nursing child. The enteric coating on Asacol that keeps it from breaking down too quickly once ingested, does contain an ingredient called dibutyl phthalate (DBP). In animal studies, where high doses were given to subjects, DBP has been associated with some adverse effects. But these experimental levels are much higher than the prescribed dose for humans. Women taking sulfasalazine should also be taking a folate supplement because sulfasalazine decreases folate stores in the body.
Corticosteroids are frequently used to control inflammation in patients with Crohn's or colitis, especially during flares. Though corticosteroids are usually effective for symptoms control, long-term use increases the risk of numerous side effects. When the potential benefit of putting your disease in remission outweighs the risks of the medication, your doctor may prescribe short-term use of corticosteroids. Prednisone, prednisolone and methylprednisolone are the corticosteroids of choice since they metabolize better for the developing fetus. The majority of studies do not show an increased risk of congenital abnormalities with use of corticosteroids. Some older studies show a possible association between corticosteroids and the development of cleft palate but this has not been shown in more recent studies. Breastfeeding while taking corticosteroids is considered safe.
Azathioprine (AZ) and 6-mercaptopurine (6-MP) are frequently used in combination to treat Crohn's disease and ulcerative colitis. These immune system suppressants reduce inflammation by making the immune system less active. The current recommendation is to continue using AZ and 6-MP during pregnancy. Some animal studies have shown some malformations, but again, the animal subjects were given much higher doses of each medication than would be prescribed to humans. One study has shown trace levels of 6-MP in breast milk within the first four hours of taking the medication. Some physicians will recommend not using breast milk produced within the first four hours after taking the medication. But, overall the risk to nursing babies is very low.
Infliximab and adalimumab
Infliximab and adalimumab are biologics that are designed to block or protect the body from tumor necrosis factor (TNF), which is the inflammatory response that occurs in Crohn's and colitis. There is no data to suggest that these medications could alter the development of the fetal immune system. However in order to reduce the possible risk, some experts have recommended that these drugs be stopped around 22 weeks into the pregnancy. This recommendation is based on the finding that these drugs are not transported across the placenta until 22 weeks into pregnancy. Alternatively, some experts also recommend continuing the drug throughout pregnancy as discontinuing use also increases the risk of disease flares and possible reactions to the drug when restarting the regimen after pregnancy.
Studies of infliximab and adalimumab (both before and after 22 weeks of gestation) have shown that there is no increase in congenital abnormalities when compared to those not taking these medications. Mothers on these biologics who are also taking azathioprine as a type of combination therapy have shown a tendency to deliver earlier than mothers not using combination therapy. However, we do not know if this is a drug effect or if this is due to the mother having more active disease. In addition, newborns exposed to infliximab and adalimumab during fetal development did not show a higher risk of infection during the first year of life. Passing these medications on to the infant through breastfeeding carries a very low risk as there is zero to minimal drug detectable in the breastmilk.
But, because infliximab and adalimumab can be detected in the infant, live vaccines such as Bacillus Calmette-Guerin (or BCG, for protection against tuberculosis), rotavirus (inflammation of the small intestine that leads to vomiting and severe diarrhea), mumps/measles/rubella and varicella zoster (chickenpox) should not be given during the first six months following delivery.
A recent addition to medications used to treat moderate to severe Crohn's or colitis is golimumab. According to the manufacturer, there have been 47 reported cases of women who have received golimumab during pregnancy and no reported congenital abnormalities among the live births. To date, there are no published studies that have compared the use of golimumab with a control group that did not receive the drug. But, because golimumab is in the same family of biologics as infliximab and adalimumab, the drug can be transported across the placenta to the child.