Emergency cesarean section in dogs: Usefulness of amniotic fluid biochemical parameters and placental morphology as indicators of neonatal viability

Abstract

In recent years, special attention has been paid to the analysis of fetal fluids and placental histopathology to identify parameters that can be used as indicators of maternal reproductive quality, embryonic viability, and fetal and neonatal health. Newborn health reflects the functioning of the fetal adnexa and its relationship with maternal tissues. Therefore, evaluating these components is promising for the early detection of newborns at risk. This study aimed to detect the biochemical characteristics of the amniotic fluid (AF) and histopathological characteristics of the placenta for comparison between canine neonates born by elective (EL) and emergency (EM) cesarean sections (CSs) and associate the results with neonatal viability in the first 24 h. A total of 38 neonates born by ELCS (n = 19) and EMCS (n = 19) were selected. AF was collected to analyze the concentration of its biochemical components [alanine aminotransferase (ALT), alkaline phosphatase (ALP), creatinine, urea, total protein, albumin, total and direct bilirubin, lactate, glucose, potassium, chloride, calcium, and sodium]. Histopathological processing of the placenta was used to describe the lesions and identify the arrangement of collagen fibers using hematoxylin-eosin and picrosirius staining. There was an increase in ALP activity (P = 0.035) and the concentrations of lactate (P < 0.001) and potassium (P = 0.031), and a decrease in chlorides (P < 0.001) in the AF of neonates in the EMCS group. The comparisons between the groups did not show differences between the presence and extent of lesions in the placenta; however, a difference was observed in the arrangement of collagen fibers in the placental structure. A comparison between AF and histopathological findings showed a negative correlation (r = -0.609, P = 0.003) between glucose concentration and the presence of necrosis in the placental labyrinth. It was observed that the composition of the AF changed owing to the influence of the type of cesarean, possibly caused by prolonged hypoxia in cases of dystocia. ALP activity and lactate, potassium, and chloride concentrations in the AF might be explored as markers of neonatal health in EMCS. Under the conditions of this study, no correlations were found between the placenta's histopathological characteristics and the neonates' viability.

Keywords: Collagen; Dystocia; Histopathology; Hypoxia; Reproduction.