The presence of antiphospholipid antibodies (APA) in the blood stream is associated with some reproductive disorders in women. In the serum of 84 pregnant women, using the Elisa method, anticardiolipin antibodies (ACA) were examined. The first group of 53 women was formed by women with pathological levels of at least one of the oncofoetal antigens (alpha-1-fetoprotein-AFP, human chorionic gonadotropin-HCG and trophoblast-specific beta-1-glycoprotein- SP1). The second group of 31 pregnant women comprised women hospitalized on account of a risk pregnancy. In the first group women with reduced HCG were most frequently represented, where in 8.8% positive ACA were recorded. Of 11 patients with elevated HCG only in one the presence of ACA was detected. In nine pregnant women with reduced HCG and SP1 or AFP ACA positivity was found in 44.4%. In the second group ACA were detected in the serum of six pregnant women who had also pathological SP1 or HCG levels. From the results ensues that ACA could interfere with transduction signalizing processes in the cell and thus influence the synthesis of some proteins.