Analysis of circulating annexin A5 parameters during pregnancy: Absence of differences between women with recurrent spontaneous pregnancy losses and controls

Objective We investigated whether levels of annexin A5 (AnxA5), AnxA5 anticoagulant activity and binding, and anti-AnxA5 antibodies might be altered in women with previous histories of recurrent spontaneous pregnancy losses (RSPL) when tested during pregnancy. Study design Ninety pregnant women with histories of 3 or more RSPL (cases) and 150 women without adverse pregnancy histories (controls) were assayed for these AnxA5 parameters. Results There were no significant differences between cases and controls in AnxA5 levels (median, 23.1 ng/mL [range, 2.1-201.1 ng/mL] vs 19.7 ng/mL [2.1-151.5 ng/mL]; P = .20), AnxA5 anticoagulant activity (183% [101%-236%] vs 168% [128%-256%]; P = .39) and binding (6.0 ng/aliquot PL [2.1-19.5 ng/aliquot PL) vs 6.1 ng/aliquot PL [1.6-16.8 ng/aliquot PL]; P = .72), and anti-AnxA5 antibody levels. Conclusions AnxA5 parameters do not distinguish between cases and controls when tested during pregnancy. The pregnant state itself appears to be associated with altered levels of AnxA5 parameters.