THE PREVALENCE OF LUPUS ANTICOAGULANT AND ANTICARDIOLIPIN ANTIBODIES IN WOMEN WITH A HISTORY OF FIRST TRIMESTER MISCARRIAGES

Objective To determine the prevalence of lupus anticoagulant and raised anticardiolipin antibodies in women with a history of two or more miscarriages in the first trimester of pregnancy. Design A prospective study of lupus anticoagulant and anticardiolipin antibody levels in unselected women with a history of two or more first trimester miscarriages. Setting The prepregnancy clinic and miscarriage antenatal clinic in a tertiary referral centre. Subjects Two hundred and forty-three women, of whom 113 (47%) had a past history of two miscarriages, and 130 (53%) had three or more miscarriages. Main outcome measures Quantitative detection of lupus anticoagulant and anticardiolipin antibodies; number of miscarriages in women in the normal and the abnormal groups. Results Of the 243 women tested, 41 (16.8%) had an abnormality of lupus anticoagulant or anticardiolipin antibodies. This was significantly different from the normal population as previously reported. Sixteen women (6.6%) were positive for lupus anticoagulant, 20 (8.2%) had elevated anticardiolipin antibodies, and five (2%) had both abnormalities. The most frequently positive test for lupus anticoagulant was the dilute Russel viper venom time, and IgG was the most frequently elevated anticardiolipin antibody. Of the women with a history of only two miscarriages, 15% had an abnormality of lupus anticoagulant or anticardiolipin antibodies, compared with 185% of those with a history of three or more miscarriages. This did not reach statistical significance. There were 117 (48%) primary miscarriers and 126 (52%) secondary miscarriers. Of the primary miscarriers, 17% had an abnormality, compared to 18% of the secondary miscarriers. Conclusions These findings provide further evidence of an association between lupus anticoagulant and anticardiolipin antibodies and early pregnancy loss. It is not known if these are the cause of miscarriage, markers for miscarriage, or if antiphospholipid antibodies develop as a result of a noncontinuing pregnancy. Further studies comparing various treatments are required before women with these antibodies can be optimally managed.