Antiphospholipid antibodies and human reproductive failure

Routine screening for circulating antiphospholipid antibodies (aPL), namely the lupus anticoagulant (LA) and anticardiolipin antibodies (aCL), was carried out in a total of 1273 women aged < 45 years. Of them, 822 were experimental subjects and 451 were controls. The former comprised the following three study groups: 498 infertile patients (group 1), 284 spontaneous recurrent aborters (group 2), and 40 patients with repeated failure of embryo transfer (group 3). Controls included five groups of women: 125 normal healthy women who had never been pregnant (group 4), 125 normal healthy parous women with no previous abortion (group 5), 52 women in labour after normal pregnancies at term (group 6), 49 infertile patients achieving a livebirth with their first in-vitro fertilization (IVF) and embryo transfer (group 7), and 100 female patients with systemic lupus erythematosus (positive controls, group 8). aPL positivity in the eight groups studied was as follows: 24, 9.2, 10, 0.8, 0, 0, 0 and 42% respectively for groups 1 to 8. There were no differences within groups 1 and 3 regarding incidence of aPL when patients were grouped according to infertility aetiological factors and indications of IVF respectively. Twenty-six out of 284 recurrent aborters (9.2%) tested positive for aPL, and the LA and/or a CL were identified as the aetiological factor in 12% of patients (24/199) with supposedly unexplained recurrent abortion. Incidence of positive sera for aPL in group 1 was similar to that observed in control groups 4, 5 and 6. On the contrary, incidence of aPL positivity in groups 2 and 3 was significantly higher than in control groups 4, 5 and 6 and among infertile women (group 1). The difference between groups 3 and 7 almost reached statistical significance. Interestingly, there was no difference between groups 2 and 3, but groups 2 and 7 resulted probably different regarding incidence of aPL positive sera. As expected, the highest incidence of patients testing positive for aPL was found in group 8. Seven infertile patients having circulating aPL and becoming pregnant spontaneously or after specific infertility treatment, successfully carried to term in spite of the fact that they did not receive immunotherapy. Among recurrent aborters, the live-born baby rate was significantly higher after treatment with low-dose aspirin than prior therapy. It is concluded that the presence of circulating aPL may be associated with recurrent abortion but with infertility. In addition, our results favour a possible role of aPL in failure of implantation after IVF embryo transfer.