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Background and Objectives: Haemorrhage is a leading cause of mortality and morbidity of mother and foetus. Pregnancy is associated with changes which may influence responses to bleeding. This study was designed to examine the influence of controlled haemorrhage and compare thermoregulation and haematological and biochemical parameters in pregnant and nonpregnant rabbits.
Materials and Methods: Twelve pregnant and nonpregnant rabbits, 6 in each group, were used in the studies. Both groups of animals were subjected to 20% haemorrhage of total blood volume on gestation day 21. The rectal temperature (Tr), respiratory rate (RR) and heart rate (HR) were monitored for 2 days following bleeding. Blood samples were collected at 24 hrs before induction of bleeding and then after bleeding at 30 min, 24 hrs and 48 hrs. The samples were used for measurements of haematological parameters; coagulation profile, arterial blood gases and serum electrolytes.
Results: The general trend indicates lower Tr values in pregnant rabbits at 30 min post-haemorrhage. The values of RR and HR were significantly (P ≤ 0.01) higher in pregnant and nonpregnant animals at 24 hrs post-haemorrhage. The pregnant rabbits showed significant (P<0.05) decrease in platelets count at 24 hrs post-haemorrhage compared to the nonpregnant values. In pregnant rabbits, haemorrhage was associated with significant increase in PT. The activated partial thromboplastin time (APTT) was significantly (P≤ 0.01) prolonged at 24 hrs post-haemorrhage in pregnant and nonpregnant rabbits. The partial pressure of arterial oxygen (PaO2) in pregnant and nonpregnant rabbits was significantly (P≤ 0.01) increased at 24hrs and 48 hrs post-haemorrhage. The partial pressure of arterial carbon dioxide (PaCO2) decreased significantly (P≤0.01) at 30 min post-haemorrhage in pregnant rabbits. There was a slight increase in Na and Ca levels in pregnant rabbits’ post-haemorrhage. Haemorrhage in rabbits was associated with significant decreases in plasma osmolality in pregnant rabbits.
Conclusion: Pregnancy induces modifications in some physiological responses to haemorrhage. The information generated could be used in monitoring maternal health during pregnancy and risks of changes associated with haemorrhage in mammals.