Maternal serum ADAM12 levels correlate with PAPP-A levels during the first trimester.

Background: We wished to investigate the correlation between a new Down screening marker ADAM12 (a disintegrin and metalloproteinase-12) and pregnancy-associated plasma protein-A (PAPP-A) and free beta-human chorionic gonadotropin (fbeta-hCG) during the first trimester of pregnancy.

Methods: ADAM12, PAPP-A and fbeta-hCG were measured in 225 serum samples of randomly chosen pregnancies with completely normal outcome. The samples were taken between pregnancy weeks 9+0 and 12+6.

Results: The ADAM12 levels tended to increase with advanced gestational age and the highest levels were detected at pregnancy week 12. The ADAM12 levels correlated with PAPP-A levels. After weight correction and logarithmic transformation the multiples of median (MoM) of ADAM12 still correlated with the MoMs of PAPP-A and also with the MoMs of fbeta-hCG. Smokers had lower ADAM12 levels than non-smokers.

Conclusion: The secretion of ADAM12 seems to resemble the secretion of PAPP-A in the end of the first trimester. Accordingly ADAM12 appears not to be a separate marker independent of PAPP-A. It remains to be assessed whether adding ADAM12 in Down screening risk calculation will reduce the false positive rate during the first trimester of pregnancy.