AMINOTERMINAL PROPEPTIDE OF TYPE-III PROCOLLAGEN IN CORD-BLOOD AND AMNIOTIC-FLUID OF APPROPRIATE-FOR-GESTATIONAL-AGE INFANTS - A PREDICTOR OF AGE-RELATED FETAL GROWTH-RATE

Procollagen propeptide serum levels reflect the rate of collagen produ ction. Because the prenatal period is unrivaled in terms of relative a mounts of collagen synthesized per unit of time, this life episode mus t be the most sensitive period for the study of these biochemical mark ers of growth variability. N-terminal propeptide of type III procollag en (PIIINP) concentration was measured by two different methods (Fab'- fragment and whole antibody-based RIA assay) on paired samples of cord serum and amniotic fluid from a study cohort of 602 perinates with ge stational age ranging from 20 to 41 wk. The aim of this study is to as sess the clinical usefulness of the PIIINP assay for the evaluation of fetal somatic growth variation during the second half of normal pregn ancies. It was demonstrated that the PIIINP level in cord serum, as we ll as in amniotic fluid, reflects age-related growth activity in ''hea lthy'' fetuses (n = 504) with normal intrauterine growth. This reflect ion was independent of the cumulative body mass or length already atta ined at the time of investigation. The PIIINP concentration closely mi rrors the shape of the fetal somatic growth velocity curve, expressed as weight-specific gain (g/kg/d) during the second half of pregnancy. It can be concluded that PIIINP level in cord blood or amniotic fluid of fetuses with normal intrauterine growth is an interesting parameter for the assessment of maturity-related fetal growth potential.