Abstract
Crosman 1 recently stated that the average leucocyte count of the pregnant albino rat is approximately 7,000 to 10,000 higher than that of non-pregnant animals. Comparison with our data on pregnant and non-pregnant rats respectively, shows that there is such great fluctuation in the counts of individual rats that only averages from a long series are significant in this regard. Our average count for the leucocytes of the pregnant female rat throughout the last third of pregnancy (16 to 22 days) is 10,758 per cu. mm. of blood as against 12,372 for our non-pregnant animals. (Table I.) These results suggest a decrease in the average count of the leucocytes during the last third of pregnancy. Certainly no leucocyte increase occurs. A high peak appears in one maternal count at the time when the fetuses are from 23 to 27 mm. long (19th day), namely, 16,000 cells. The fact that 3 other rats with fetuses at this same stage of development showed a similar increase arrests attention. However, we do not consider it justifiable to conclude that there is a significant increase of leucocytes during pregnancy.
To further check our results we have compared them with the average leucocyte counts for non-pregnant rats given by Adams and Shevket2 from Wistar stock and from Mt. Holyoke stock respectively. In the Wistar stock these investigators report an average leucocyte count of 12,540 per cu. mm.; and in the Mt. Holyoke stock 10,750. When compared with these averages, our counts show no significant discrepancy.
The erythrocyte counts from pregnant and non-pregnant rats show such a slight difference that we conclude that there is no change in the average count during pregnancy. The average erythrocyte count for 28 non-pregnant females is 9,336,071 per cu. mm.; and for 29 pregnant animals 8,086,551.
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