Amniotic fluid levels of CA 19.9 and CA 15.3 in normal and Down's syndrome pregnancies.

CA 125, CA 19.9 and CA 15.3 are antigenic determinants on glycoproteins commonly used as serum markers in gynecologic oncology. CA 125 was also investigated in the amniotic compartment of Down's syndrome pregnancies. The objective of this study was to evaluate the concentration of CA 19.9 and CA 15.3 in the amniotic fluid of normal and Down pregnancies. The concentration of these antigens was measured in stored amniotic fluid samples from 15-19 weeks pregnancies with and without Down's syndrome fetuses and expressed in multiples of the median for normal pregnancies of the same gestational age. The study group included 20 samples selected from single Down's syndrome pregnancies. Each of these samples were matched with three control samples from unaffected pregnancies, matched for maternal age, gestational age and duration of storage of the sample. The median MoM values of CA 19.9 and CA 15.3 in Down's syndrome pregnancies were respectively 1.11 MoM and 1.16 MoM, not significantly different from those of unaffected pregnancies (CA 19.9: 1.02 MoM; CA 15.3: 0.99 MoM). In the present study we have not found significantly different levels of CA 19.9 and CA 15.3 in the amniotic fluid of fetuses affected by Down's syndrome and in the controls.