Association of quantitative anticardiolipin antibody levels with fetal loss and time of loss in systemic lupus erythematosus.

The presence of anticardiolipin antibodies has been associated with the occurrence of spontaneous abortions in patients with systemic lupus erythematosus. Retrospective analysis of the relationship between the levels of IgG and IgM anticardiolipin antibodies in 84 patients with SLE and the prevalence of spontaneous abortions was performed. The time at which abortion occurred amongst these patients was compared with that in 26 subjects with a poor obstetric history, but without SLE. Forty-six of 84 patients had anticardiolipin antibodies and had 143 pregnancies, of which 84 (58.7 per cent) resulted in fetal loss. In contrast, amongst the 38 patients without anticardiolipin antibodies only 23 of 93 pregnancies (24.7 per cent) resulted in fetal loss. The prevalence of spontaneous abortions in the SLE patients was related to the levels of IgG anticardiolipin antibodies; IgM anticardiolipin antibodies were not associated with increased fetal loss. In SLE patients without anticardiolipin antibodies, and in the group of patients without SLE, fetal loss occurred at 14.1 +/- 7.5 (mean +/- SD) and 12.5 +/- 5.5 weeks respectively. When anticardiolipin antibodies were present fetal loss tended to occur at a later stage of pregnancy (17.4 +/- 7.1 weeks) and amongst this group 30 per cent of the pregnancy losses were in the third trimester of pregnancy. These findings demonstrate further that anticardiolipin antibodies are strongly linked to late pregnancy failure in patients with SLE.