Canine pulmonary clearance during feto-neonatal transition according to the type of delivery.

The success of immediate adaptation to extrauterine life depends on appropriate lung function, however, elective cesarean section can increase the risk of respiratory distress as a result of reduced pulmonary fluid absorption. This study aimed to evaluate the influence of birth mode on pulmonary clearance and respiratory performance of canine neonates in the transition period. For this purpose, 37 neonates were selected according to the obstetric condition: Vaginal Eutocia (n = 17) and Elective C-section (n = 20). Neonates were evaluated for neonatal vitality score, as well as evaluation of heart and respiratory rates, body temperature and body weight, venous hemogasometric evaluation, blood lactate and glucose, pulse oximetry and radiographic evaluation during the first 24 h of life. Additionally, amniotic fluid electrolyte composition of each puppy was evaluated. There was no influence of the type of delivery on electrolyte composition of canine amniotic fluid and neonatal pulmonary liquid content, analyzed by thoracic X-Rays. On the other hand, elective cesarean section delayed pulmonary adaptation, resulting in hypoxemia and less efficient compensatory response to acid-base imbalance and thermoregulation. In conclusion, elective c-section does not delay pulmonary clearance, whilst alters pulmonary adaptation by less efficient gas exchange and lower oxygenation, hindering the compensatory response to acid-base imbalance during the fetal-neonatal transition in dogs.

Maternal and neonatal cortisol and catecholamines throughout vaginal eutocia and C-section in dogs.

Increased fetal cortisol is associated with catecholamine release, a primary factor for neonatal adaptive responses. However, relationship between canine peripartum cortisol and catecholamine is unknown. We aimed to compare serum adrenaline, noradrenaline and cortisol during peripartum in bitches and neonates of distinct obstetric conditions and to assess amniotic fluid cortisol concentration. Twenty females and maximum of three puppies per litter were allocated into Vaginal Eutocia (10 females; 17 neonates) and Elective C-section (10 females; 20 neonates) groups. Amniotic fluid was collected at delivery for cortisol concentration. Maternal and neonatal blood were collected prepartum, intrapartum, postpartum and 1h postpartum, and at birth, 30 and 60min, 12hs and 24hs, respectively, for cortisol, adrenaline and noradrenaline assessment. C-section determined higher noradrenaline throughout delivery and cortisol concentration from intrapartum through 1h postpartum, compared to vaginal birth. C-section maternal cortisol showed progressive increase from intrapartum onwards, while neonatal cortisol remained unchanged. No difference of maternal cortisol concentration occurred along whelping, whereas a significant decrease was verified for vaginal delivery puppies from birth until the 12hs. Puppies delivered vaginally had higher cortisol concentration at birth and 30min, compared to c-section puppies. There was a higher concentration of amniotic fluid cortisol in vaginal eutocia. In conclusion, c-section induces higher maternal stress during and after surgery, whilst vaginal delivery is a more neonatal physiologically stressful condition, contributing to better adaptation during transition.

Both spontaneous vaginal delivery and elective caesarean section influence neonatal redox status in dogs.

BACKGROUND: The influence of birth mode on redox balance is unknown in dogs. We aimed to compare antioxidant activity and oxidative stress of puppies born by elective c-section or vaginal delivery. METHODS: Twenty-one bitches were elected for spontaneous vaginal delivery (n = 10) and elective cesarean section (n = 11) groups, considering only the first and last puppies born. Neonatal oxygen saturation, lactatemia, superoxide dismutase (SOD), reduced glutathione (GSH), glutathione peroxidase (GPx) and total antioxidant capacity; marker of oxidative stress (thiobarbituric acid reactive substances [TBARS]) and protein oxidation were analysed at birth, 1 h, 12 h, 24 h and 72 h. RESULTS: C-section newborns had lower oximetry at birth and 1 h. Lactatemia was higher in the last vaginal delivery puppies and higher at birth, and 1 h. Regardless of birth mode, last puppies had hyperlactatemia at birth. Vaginal delivery puppies had higher TBARS, while protein oxidation was higher in c-section, mostly in last puppies. C-section puppies had higher GPx activity, whereas GSH concentration decreased overtime. Surgically born puppies had lowering SOD between 12 h and 72 h. CONCLUSIONS: Vaginal delivery enhances lipid peroxidation, counteracted mostly by GPx. Conversely, c-section triggers protein oxidation, acutely scavenged by SOD and GSH, thus puppies are less exposed to the negative consequences of oxidative stress.