A critical assessment of the role of antiphospholipid antibodies in infertility

Antiphospholipid antibodies (aPL) are a family of autoantibodies that are associated with pregnancy complications including stillbirth and recurrent miscarriage. Infertile women, and those with recurrent IVF implantation failure, have an increased incidence of aPL (22% and 30%, respectively) compared with a healthy, fertile population (1–3%). Despite this increased incidence, aPL are not predictive of an adverse outcome from IVF. In this review we critically assess the literature in this field, which we believe to be awash with poorly designed studies. Our main criticism is that studies have not examined the fertility outcomes for individual aPL, but rather have examined outcomes for women with between one and eight different aPL. The wide range of antibodies tested and collectively analyzed means that any clinically relevant effects of a specific antibody would be undetectable, if such effects exist. It is also difficult to envisage how aPL present in the maternal blood might damage zygotes or embryos in order to induce infertility. We review the experimental data, looking at possible mechanisms by which aPL might induce infertility. Despite the multiplicity of studies we demonstrate in this review that the question of whether aPL are associated with, or cause, reduced fertility remains unanswered. We also demonstrate that there is no evidence that supposedly aPL-induced infertility or implantation failure after IVF can be treated with pharmacological interventions.