The Concentrations of Markers of Bone Turnover in Normal Pregnancy and Preeclampsia

Background. The purpose of our study was to investigate the concentrations of markers of bone turnover in normal pregnancy and preeclampsia. Material and Methods. Forty-five pregnant patients with preeclampsia, 78 healthy pregnant women (26 in first, 26 in the second, and 26 in third trimester of pregnancy), and 20 nonpregnant women were included in the study. Serum concentrations of osteoprotegrin (OPG), receptor activator of nuclear factor kappa B ligand (sRANKL), and the markers of bone turnover, osteocalcin and CrossLaps-degradation products of type I collagen, were determined using the ELISA method. Statistical analysis was performed using Mann-Whitney U-test. Results. The concentrations of sRANKL and OPG were significantly higher in the second trimester of normal pregnancy when compared to the first and the third trimesters and to nonpregnant controls. The concentrations of osteocalcin were significantly higher in the first trimester of physiological pregnancy in comparison with nonpregnant women and with second and third trimesters of pregnancy. The concentrations of CrossLaps were significantly higher in the second trimester of normal pregnancy when compared to the first and third trimester. In preeclampsia, the sera concentrations of osteocalcin and CrossLaps were significantly higher when compared to the third trimester of normal pregnancy. Conclusion. The results suggest that the bone formation is increased in the first trimester, whereas the bone resorption is increased in the second trimester of normal pregnancy. Furthermore, the results suggest that the bone turnover is increased in patients with preeclampsia when compared to healthy normotensive pregnant women.