The relationship of fetal serum markers of bone metabolism to gestational age

The aim of this study is to determine the pattern of fetal bone metabolism by measuring umbilical cord levels of carboxy terminal pro-peptide of type I pro-collagen (PICP) and cross-linked carboxyterminal telopeptide of type I collagen (ICTP). PICP and ICTP directly monitors the rate of bone formation and resorption, respectively. Samples were obtained at the time of delivery from 20 healthy women with pregnancies at different gestations. There is a significant inverse correlation between fetal levels of PICP and ICTP, and gestation (PICP r = -0.504, p = 0.023; ICTP r = -0.713, p < 0.001), and between ICTP and birth weight (r = -0.466, p = 0.038), but the birth weight effect is a function of gestational age. Therefore, both bone formation and resorption decrease with gestational age. Although contrary to the suggestion that fetal ossification increases at the end of pregnancy, such changes may be due to the shift from growth to maintenance. (C) 1998 Elsevier Science Ireland Ltd.