This is what I found when I looked up salazopyrin (which is the brand name) online and in my pharmacology textbook.

Pregnancy-Sulfasalazine/Sulphasalazine has not been studied in pregnant women. However, reports on women who took sulfasalazine during pregnancy have not shown that it causes birth defects or other problems. In addition, sulfasalazine has not been shown to cause birth defects in studies in rats and rabbits given doses of up to 6 times the human dose.

It is used to treat ulcerative colitis, Chron's disease, as well as Rheumatoid arthiritis.

My Pharmacology text actually says its in catgeory A - which is supposedly safe to take in pregnancy.

But definately check with your Dr before taking any medications during pregnancy.