Biochemical analysis of catecholamine and cortisol for the evaluation of the fetal distress in third trimester stillbirths.

Background: Stress hormones like catecholamine and cortisol are thought to reflect the magnitude of physical stress in adults and were studied in relationship to the cause of death and agony time. Intrauterine distress, intrapartum events, and modes of delivery can affect the fetal endocrine stress response, as reflected by biochemical analyses. The aim of the present study was to evaluate the role of catecholamines and cortisol as markers of ante-mortem fetal distress. The role of cortisol as a marker of circadian timing of delivery was also assessed.

Methods: A 2-year prospective cohort-comparison inclusion of stillbirths and newborns took place with collection of antemortem data, labor parameters, neonatal outcome, post-mortem data and blood samples. Stillbirths were classified as acute or chronic on the basis of a multidisciplinary evaluation. Heart blood of stillbirths and cord blood of newborns were analyzed by high pressure liquid chromatography (HPLC) for adrenaline and noradrenaline and by immunoassay for cortisol determination.

Results: Fifteen stillbirths and 46 newborns, as a comparison group, delivered by spontaneous vaginal birth, elective, and emergency cesarean sections were included. Stillbirths' main cause of death was cord thrombosis. Levels of adrenaline and noradrenaline (median: 14,188 pg/ml and 230.5 pg/ml, respectively) were significantly higher (p < 0.001) in stillbirths than in newborns and were also higher in acute compared to chronic distress. Cortisol levels were significantly higher (p < 0.05) in spontaneous vaginal delivery (median: 18.2 μg/dl) compared to elective cesarean sections (median: 3.8 μg/dl). No difference in cortisol concentrations was detected between newborns delivered at morning and at afternoon/evening.

Conclusion: Our results suggest that the biochemical measurement of adrenaline and noradrenaline levels might reflect a marked physical stress response during the process of death in stillbirths. On the contrary, the elevation of cortisol levels could mirror the elevation in maternal cortisol level during vaginal delivery. For the post-mortem evaluation of stillbirths, the analysis of CA levels could provide additional data on the duration of distress, useful to integrate the forensic diagnosis.