Antiphospholipid antibodies circulate in the bloodstream, can bind to cell membranes, and may cause small clots to form. They have various names such as lupus, cardiolipin and antinuclear antibodies. They are found in 2-15% of the population, even in men.

It has been shown that women who have recurrent miscarriages have a higher incidence of antiphospholipid antibodies (APAs), and the use of the anticoagulant heparin, or aspirin, may reduce this risk. This treatment has been used for 10 years.

A theoretical extension of the “recurrent miscarriage” theory, is that in some women who have recurrent IVF failures, APAs may be responsible. Monash IVF studied the incidence of antiphospholipid antibodies (sending samples to the USA) and their effect on the outcome of IVF treatment, but found no evidence of an association. This has also been the experience of large controlled trials in the USA, so we have concluded that there is no evidence for their importance. Furthermore treatment of IVF patients with APAs has not produced improved success rates in controlled studies overseas.

There is evidence of a possible relationship between blood clotting factors and IVF success rates and Monash IVF. Clinicians sometimes do refer patients to haematologists for screening for their clotting factors.