In the pregnant state, NSAIDs are contraindicated in the third trimester and though they can be taken early in pregnancy, they are not strongly recommended. There is some animal data (not human) suggesting NSAIDs interfere with implantation (getting pregnant) and human data suggesting an increased risk of miscarriage with NSAID use early in pregnancy. Specific NSAIDs like celecoxib are not recommended in pregnancy. Though we do not recommend traditional medications like methotrexate (rheumatrex), leflunomide (arava) and sulfasalazine in AxSpA treatment, they are nevertheless sometimes used in patients. Methotrexate and leflunomide are strongly contraindicated in pregnancy and are associated with fetal malformation and birth defects.
Sulfasalazine is safe in pregnancy, though higher doses of folic acid supplementation may be warranted. TNFi are being used more and more in the pregnant state. In fact, one of them in particular, certolizumab pegol (Cimzia), does not cross the placenta or into breast milk and has a pregnancy indication. In general, TNFi are especially safe until 20 weeks. From 20 weeks on, the placenta starts to build the baby’s immune system by avidly transporting antibodies from mother to baby. This includes drugs that are antibodies like the TNFi (except certolizumab). It is recommended that if TNFi other than certolizumab are used, they are stopped before the third trimester, whereas certolizumab can be continued though the duration of pregnancy. The major issue is that once the antibodies (and drug) cross the placenta, they remain in the baby’s system for months after delivery and at a higher dose than the mom’s own drug level. In theory this would increase the baby’s risk of infection, though studies have not suggested this. It may be that patients are stopping their biologic early enough in pregnancy to prevent this exposure. Most importantly, if a fetus has been exposed to a biologic, especially in the second trimester, live vaccines should be avoided for the first six months of life.