Lupus anticoagulant and anticardiolipin antibodies in an obstetric population.

Lupus anticoagulant (LA) and anticardiolipin antibodies (ACA) have been reported to be associated with fetal loss. OBJECTIVE. Our aim was to estimate the incidence of LA and to examine the correlation between LA and ACA in pregnant women. To investigate the clinical significance of LA and ACA in an obstetric population. STUDY DESIGN. A prospective, cross sectional study of 2856 consecutive women admitted to a department of obstetrics and gynecology for delivery or due to pregnancy complications during an 11 month period. METHODS. Activated partial thromboplastin time (APTT) was determined in all patients. LA and ACA were determined if APTT > or = 35 sec. For reference ACA was determined in a group of randomly selected patients with APTT < 35 sec. The results were analyzed in relation to the obstetrical records. RESULTS. Overall incidence of APTT > or = 35 sec.: 7.0%, significantly more frequent in patients with early spontaneous abortion (18.6%) and intrauterine growth retardation (17.5%). Incidence of LA 0.07%. The patients had undetectable ACA and no clinical condition related to LA. Incidence of ACA class IgM (IgM-ACA) in patients with APTT > or = 35: 20.4%, significantly higher than in the reference group (9.6%). Uncomplicated pregnancy in 84% of patients with IgM-ACA. No cases of ACA class IgG (IgG-ACA) in patients with APTT > or = 35 but two cases in the reference group (one normal pregnancy, one spontaneous abortion). CONCLUSION. LA is a rare manifestation with uncertain significance in otherwise healthy pregnant women. IgM-ACA in low titer occurs relatively frequently during normal pregnancy.