Changes in clinical pathology parameters during gestation in the New Zealand White rabbit

Hematology and serum chemistry parameters were analyzed in 2 groups of pregnant rabbits to assess changes in these parameters over the course of gestation. These data were used to generate a historical control reference range for embryofetal development regulatory toxicology studies. During the 28-day gestation period, the following major changes were observed. Red blood cell counts, hemoglobin, and hematocrit increased slightly up to day 13 and subsequently decreased progressively to a nadir for all parameters on day 25. Reticulocyte counts increased maximally by day 16 and then decreased to a minimum value on day 28. White blood cell counts progressively declined after day 7. Platelet counts increased slightly by day 10, were relatively stable until day 13, then progressively decreased to a nadir on day 25. Aspartate aminotransferase and alanine aminotransferease values increased steadily throughout the study to reach a maximum value on day 25. Triglycerides increased to their maximum value by day 19 and then steadily decreased until day 28, whereas cholesterol decreased progressively to reach a nadir on day 25. Urea and total protein decreased steadily from day 13 onward. Calcium values decreased throughout the study to reach a minimum value on day 28. Phosphorus values increased slightly on days 7 and 13 and then progressively decreased to reach a nadir on day 28. With a few exceptions, changes that occur in clinical pathology parameters during pregnancy in the rabbit are similar to those observed in pregnant women. Therefore, the rabbit can be considered a suitable species for embryofetal development toxicity studies with regard to clinical pathology.