The effects of the menstrual cycle, pregnancy and early lactation on haematology and plasma biochemistry in the baboon (Papio hamadryas)

The changes in the haematology and clinical biochemistry associated with th e different stages of the menstrual cycle, gestation and lactation in the b aboon (Papio hamadryas) were evaluated in a prospective longitudinal study. Serial EDTA and heparin blood samples were collected from 12 baboons. Haem oglobin concentration, haematorcrit, red blood cell and white blood cell co unts were decreased in the luteal compared to the follicular phase (P < 0.0 01): the reverse effect was observed for platelet count, total protein and albumin concentrations. The changes in plasma concentrations of sodium, pot assium, urea, creatinine and cholesterol and plasma osmolality were charact erized by reductions (P < 0.01) in early pregnancy which were maintained th roughout gestation. Plasma concentrations of total protein, albumin and alk aline phosphatase, as well as haemoglobin, haematocrit and red cell count w ere reduced (P < 0.001) from mid-gestation. Platelet count and plasma calci um concentration fell continuously throughout gestation (P < 0.001). Plasma triglycerides were lower and plasma iron was higher (P < 0.01) in gestatio n compared to the phases of the menstrual cycle and lactation. By 1 week po st partum, all parameters except haemaglobin had returned to pre-conception levels.