Cortisol fetal fluids concentrations and newborn outcome in term pregnancy Chihuahua dogs : preliminary results

AIM OF THE STUDY In humans the amniotic fluid cortisol (C) concentration towards term pregnancy was associated to fetal lung maturation [1] and well correlated with gestational age [2]. To date, canine fetal fluids composition has not been completely investigated from a clinical perspective. The present study was aimed to evaluate C amniotic and allantoic concentrations in term pregnancy Chihuahua dogs, in relation to some clinical maternal and neonatal parameters, to provide information for a better management of both mothers and puppies at the time of parturition. MATERIALS AND METHODS The study enrolled 10 Chihuahua bitches, 2-5 years old, healthy at a general examination, both regularly vaccinated and dewarmed. All these bitches underwent an elective Caesarean Section (CS) at term. The parturition day was scheduled on the basis of the ovulation date estimation, on the fetal ultrasonographic measurements of both the inner chorionic cavity and biparietal diameter, and on progesteronemia. The amniotic and allantoic fluids were aseptically collected from each puppy and stored until analysis for C by RIA. At birth, the newborn puppies were evaluated for viability by Apgar score [3], maturity, gender, absence of gross malformations, and weight. Cortisol concentrations in the two types of fluids were statistically evaluated by t-test, in relation to newborn viability and gender as well as to maternal parity. RESULTS Sixteen males and 10 females normal newborns were enrolled. On the basis of Apgar score, 23 puppies had Apgar ≥ 7 and 3 Apgar < 7. According to parity, 3 bitches were primiparous and 7 multiparous. Mean (±SD) amniotic and allantoic C concentrations in total samples, in relation to newborn viability and gender as well as to maternal parity, are reported in Table 1. Table 1- Amniotic and allantoic C concentrations (mean±SD) in total samples, in relation to newborn viability and gender, and to maternal parity. Amnios Allantois Cortisol (ng/ml) Cortisol (ng/ml) Total samples 9.7±5.50 (n=19) 11.3±7.74 (n=18) Apgar ≥ 7 9.8±5.74 (n=17) 11.58±8.16 (n=16) Apgar < 7 8.5±3.61 (n=2) 9.5±3.58 (n=2) Males 9.5±6.00 (n=9) 8.5±3.69 (n=8) Females 9.7±5.61 (n=9) 14.1±10.66 (n=8) Primiparous 12.4±4.86 (n=6) 19.7±9.54 (n=5) Multiparous 8.4±5.48 (n=13) 7.9±3.84 (n=12) CONCLUSIONS In this study, the preliminary results failed to show significant differences in C levels between the two type of fluids. Additionally, significant differences in C concentrations were not found neither on the basis of newborn viability and gender nor on the basis of maternal parity. The absence of significant differences is most likely due to the small number of samples and high inter-individual variations as demonstrated by the wide SDs.