I was diagnosed with ulcerative colitis during my third month of pregnancy. I used Prednisone to control it until I was done nursing. To avoid Prednisone's side effects, I then tried all the standard drugs, finding that 6MP works best for me. I now have been using 6MP for two years. Is it safe to become pregnant again while on 6MP? What about using it throughout the pregnancy?

JAK

Ulcerative colitis is an inflammatory disease of the colon lining that typically occurs in young patients. It results in chronic, bloody diarrhea associated with abdominal cramping and weight loss.

Although the cause of ulcerative colitis is unknown, several effective medications are available to treat this disease. All these drugs act on some stage of the inflammatory cycle in the colon. Medications that contain mesalamine often work well, especially in mild to moderate cases of colitis. In more severe cases, steroids, such as Prednisone, are used.

To avoid the long-term side effects of steroids, ulcerative colitis patients often turn to 6MP, as you did. This medication is an immunosuppressive drug that is extremely effective in easing the inflammation in both ulcerative colitis and Crohn's disease. However, 6MP can cause allergic reactions, manifesting as fever, rashes, joint pains or inflammation of the pancreas or liver. In addition, 6MP lowers the white-blood-cell count, hampering the body's ability to fend off infections. Theoretically, the immunosuppression caused by 6MP can lead to the development of rare cancers. However, this has not proven to be the case in the more than 20 years that this drug has been used for colon problems.

To answer your specific concern, 6MP has been found to be safe for both mother and child during conception and throughout pregnancy. Many studies have found no increased risk of fetal birth defects or other abnormalities associated with 6MP use. Some gastroenterologists counsel their patients who are on 6MP and who wish to become pregnant that there is still a theoretical risk of a complication with the pregnancy. Keep in mind that ulcerative colitis, especially if it is not under good control, can also lead to reduced fertility and pregnancy-related complications such as premature labor. Any patient with ulcerative colitis who is pregnant, especially if she is taking 6MP, should be followed closely by both a gastroenterologist and an obstetrician.