Effect of short-term antenatal dexamethasone administration on type I collagen synthesis and degradation in preterm infants at birth

To assess the effects of antenatal corticoid administration on foetal colla gen metabolism, cord serum concentrations of the aminoterminal propeptide a nd carboxyterminal telopeptide of type I procollagen (PINP and ICTP), which reflect rates of type I collagen synthesis and degradation, respectively, were measured in 67 consecutive preterm infants with gestational ages rangi ng from 24 to 32 wk. The samples were divided into three groups, depending on the administration and timing of antenatal corticosteroid treatment for enhancement of foetal lung maturity: cases in which the mothers had receive d a full 2-dose administration of dexamethasone on consecutive days 1 to 6 d before delivery (n = 23; Complete-Dexa), those who had received only a si ngle dose of dexamethasone less than 24 h before delivery (n = 17; Partial- Dexa) and those who had not received any antenatal steroids (n = 27; No-Dex a). Infants in the Complete-Dexa group had significantly lower median PINP levels than those in the No-Dexa group (3326 vs 4028 mug/l; p = 0.036); the median PINP level in the Partial-Dexa group (3999 mug/l) was close to that of the No-Dexa group. No significant differences in ICTP concentrations we re seen between the groups. Conclusion: A significant suppression of foetal collagen synthesis but not degradation was found to be associated with antenatal dexamethasone adminis tration. This should be taken into consideration, e.g. when assessing wheth er to administer repeated or single courses of corticosteroids antenatally in high-risk pregnancies.