Relationship between antiphospholipid antibodies and recurrent fetal loss in patients with systemic lupus erythematosus and apparently healthy women.

We studied 199 patients with systemic lupus erythematosus (SLE) who had been at risk for recurrent fetal loss. Thirty-six had had recurrent fetal loss. These patients, plus a group of 38 healthy women with history of recurrent fetal loss and a group of healthy women who had had at least 3 pregnancies, were tested for antiphospholipid antibodies (APLA) of the 3 major immunoglobulin isotypes using an ELISA method with cardiolipin as antigen. Thirty of the 36 patients with SLE with recurrent fetal loss, 23 of the 163 patients with SLE without recurrent fetal loss, 3 of the 38 healthy women with recurrent fetal loss and no healthy woman with normal obstetric histories had APLA. In all but 3 of the patients with SLE with recurrent fetal loss these included APLA of the IgG isotype. Considering the odds ratio of having recurrent fetal loss as 1 for those patients with SLE without APLA, we found it to be 10.54 times higher in patients with SLE with high titer APLA. Titers of IgG APLA were also 3.2 times higher in patients with SLE with recurrent fetal loss than in those without. We conclude that recurrent fetal loss associates strongly with APLA of the IgG isotype.