Azathioprine during pregnancy in systemic lupus erythematosus patients is not associated with poor fetal outcome

The objective of this study was to evaluate the risk of adverse fetal outcome in systemic lupus erythematosus (SLE) women exposed to azathioprine during pregnancy. We reviewed the medical records of SLE pregnant women followed from January 2005 to April 2013. The patients were evaluated at least once in each trimester and postpartum. Relevant fetal outcomes were extracted, such as rate of liveborns, fetal loss (spontaneous abortion and stillbirth), term delivery, preterm birth, neonatal death, low birth weight, low birth weight at term, and congenital malformations. A detailed history of drug use during pregnancy was obtained. We studied 178 pregnancies (in 172 women), 87 of them were exposed to azathioprine (AZA-group) and the remaining 91 were not exposed (NO AZA-group). Exposure to other drugs was similar in both groups. The rate of live births, spontaneous abortions mean birth weight, weeks of gestation, rate of birth weight < 2500 g, and low birth weight at term did not differ between groups. No infant had major congenital abnormalities. Multivariate analysis showed that preeclampsia, premature rupture of membranes (PROM), lupus flare, and anti-DNA positive were associated with an increased risk of poor fetal outcome. Our study suggests that the use of azathioprine is safe and lacks of teratogenity in patients with SLE and pregnancy. Exposure to azathioprine during pregnancy is not associated with poor fetal outcome.