BACKGROUND AND OBJECTIVES: Neonatal outcomes vary by gestational age. We evaluated the association of early-term, full-term, and postterm birth with asphyxia, neurologic morbidity, and perinatal mortality.

Background: Birth asphyxia, estimated to account for a million neonatal deaths annually, can cause a wide variety of neurodevelopmental impairments. There is a need to develop new, swift methods to identify those neonates who would benefit from neuroprotective treatments such as hypothermia. Objectives: To examine the utility of cord serum copeptin, a stable byproduct of arginine vasopressin release, as a biomarker of birth asphyxia based on a comparison with 2 biomarkers of hypoxia and brain trauma: erythropoietin and S100B. Methods: The study population consisted of 140 singleton, term neonates: 113 controls and 27 with birth asphyxia (2/3 criteria met: umbilical artery pH <7.10, base excess ≤12 mmol/L, and 5-min Apgar score <7). All deliveries were planned vaginal, but 51 neonates were born by emergency cesarean section. Copeptin, S100B, and erythropoietin levels in umbilical artery samples were measured by immunoassays. Results: Copeptin correlated in the entire study population more strongly with umbilical artery base excess than S100B and erythropoietin, and only copeptin correlated with arterial pH. Furthermore, only copeptin levels were significantly higher in cases of birth asphyxia, and in vaginally born neonates they were found to increase as a function of labor duration. Copeptin was elevated in neonates born via vacuum extraction, whereas erythropoietin levels showed a slight increase after emergency cesarean section. Conclusions: In this study population, S100B and erythropoietin were not valid biomarkers of birth asphyxia. In contrast, our work suggests that copeptin has high potential to become a routinely used biomarker for acute birth asphyxia and neonatal distress.

High amniotic fluid erythropoietin concentrations are associated with decreased umbilical artery pH and base excess and with adverse neonatal outcome in pregnancies complicated by intrauterine growth restriction before 34 gestational weeks. In selected pregnancies complicated by intrauterine growth restriction, determining amniotic fluid erythropoietin could be a useful additional tool in fetal surveillance and possibly in optimizing timing of delivery.

Objective. Erythropoietin-a hormone regulating erythropoiesis-is a biomarker of chronic fetal hypoxia. High erythropoietin levels in fetal plasma and amniotic fluid are associated with increased risk of adverse neonatal outcome. Since the risk of perinatal morbidity and mortality is increased in pregnancies beyond 41 gestational weeks, we evaluated erythropoietin levels in amniotic fluid and umbilical cord serum in apparently low-risk term (≥37 gestational weeks) and prolonged pregnancies (≥41 gestational weeks) with labor induction. Study Design. This prospective cohort study comprised 93 singleton pregnancies at 37 +0-42 +1 gestational weeks, of which prolonged pregnancies numbered 63 (67.7%). Amniotic fluid samples were collected at time of labor induction by amniotomy. Umbilical cord blood samples for evaluation of pH, base excess, and umbilical cord serum erythropoietin were collected at birth. Erythropoietin levels were measured by immunochemiluminometric assay. Normal value of amniotic fluid erythropoietin level was defined as ≤3 IU/L, and abnormal value as ≥27 IU/L. Normal umbilical cord serum erythropoietin was defined as <40 IU/L. Data on maternal pregnancy and delivery characteristics and short-term neonatal outcomes such as Apgar score were obtained from the hospital charts. Associations were calculated using Spearman's rank correlation coefficient. The Chi-square test, Fisher's exact test and the Mann-Whitney U test were utilized to determine differences in the study groups. Results. Amniotic fluid erythropoietin levels correlated with gestational age (r=0.261, p=0.012) and were higher among prolonged pregnancies as compared to term pregnancies (p=0.005). There were 78 (83.9%) vaginal deliveries, and among these erythropoietin levels in amniotic fluid correlated with the levels in umbilical cord serum (r=0.513, p<0.000). Umbilical cord serum erythropoietin levels correlated with gestational age among vaginal deliveries (r=0.250, p=0.027). Erythropoietin levels in amniotic fluid and umbilical cord serum did not correlate with umbilical artery pH or base excess, or other adverse pregnancy outcome. Conclusions. In vaginal deliveries erythropoietin levels in amniotic fluid correlated with the levels in umbilical cord serum. Erythropoietin levels correlated with gestational age, probably due to weakening placental function and relative hypoxemia occurring in advanced gestation. However, in this relatively low-risk study population erythropoietin was not related to adverse delivery outcome.