Pregnancy outcome and anti-cardiolipin antibody in women with systemic lupus erythematosus

Abstract

Pregnancies in women with systemic lupus erythematosus are recognized to result in excessive fetal morbidity and mortality. Maternal autoantibody status may explain some of these problems. Anti-cardiolipin antibody has been associated with recurrent pregnancy losses in some women with lupus, but the risk of these losses has not been defined. At the University of Pittsburgh between January 1, 1979, and December 31, 1989, an unmatched case-control study design was used to determine whether patients with lupus and anti-cardiolipin antibody (81 cases) were at increased risk for adverse pregnancy outcomes in comparison with lupus patients without the antibody (174 controls). Cases had 98 of 192 (51%) pregnancies with an adverse outcome, while controls had 212 of 494 (43%). The odds ratio for having any adverse pregnancy outcome was 1.40 (95% confidence interval (CI) 0.98-1.98). When pregnancies were classified according to specific adverse outcome types, the frequency of late miscarriages (14-20 weeks gestation) in cases and controls was 8% and 3%, respectively. The odds ratio for late miscarriage was 2.94 (95% CI 1.31-6.60). When pregnancies were stratified by birth number and by occurrence of pregnancy before or after diagnosis, the increased frequency of late miscarriages in cases was noted only in the first pregnancy when the pregnancy occurred before recognized disease. Preterm births (before 38 weeks gestation) were increased in cases compared with controls in pregnancies that occurred after diagnosis for second and third pregnancies. If a case had one previous adverse outcome, the odds ratio for another adverse outcome was 3.00 (95% CI 1.62-5.57). If a case had two previous adverse outcomes, the odds ratio for a third adverse pregnancy outcome was 4.14 (95% CI 1.62-10.58). Thus, a previous adverse pregnancy outcome was the most important risk factor for an adverse outcome in a subsequent pregnancy.