Azathioprine Not Linked to Flare Risk in Lupus Nephritis Pregnancies

Rheumatologists may now reassure women with inactive lupus nephritis (LN) that they appear to be at low risk for renal flares during pregnancy if they replace mycophenolate mofetil (MMF) with azathioprine (AZA) six weeks before conception, as is often recommended to protect the fetus. German researchers report favorable results in a study of such a switch. The US Food and Drug Administration rates MMF as a class D drug that risks damage to the fetus or pregnancy.

In their study of medical records, the German team identified 54 women with inactive lupus and quiescent LN who were counselled about pregnancy. Among them, 31 were treated with AZA and 23 with MMF. In the latter group, the MMF dose was tapered, and women switched to AZA if there was no sign of renal or extra-renal flare. For the others, AZA treatment was maintained.

Among the 48 women who subsequently conceived, one woman in the MMF group and one in the AZA group experienced renal flare after delivery. Both responded to an increase in steroid dose, the researchers told the 2013 annual meeting of the European League Against Rheumatism (EULAR) in Madrid, Spain.

Renal function did not worsen in any of the patients, during a mean follow-up period of 31 months postpartum.

In a logistic regression analysis, the risk for combined adverse pregnancy outcomes (miscarriage, preeclampsia and/or preterm delivery) increased with prednisone dose at baseline, with each increase in SLEDAI scores, and with older age.