妊娠時の造血機能

I. 造血小板機能

抄録

Until recently, reliable reports concerning the platelet count of pregnant women have been seldom obtained, though many papers on this matter have been published.
On the functional aspects of megakaryocytes, on the other hand, only a few reports were available, and the results of these studies seemed to remain discrepant.
Thus, the author has studied the change in platelet count during the period of maternity and puerperium on 144 normal pregnant women. The trnsition pattern of megakaryocytes in these stadia was also observed on 37 subjects. Furthermore, the changes in platelets and megakaryocytes by artificial abortion have been studied in six instances.
1) In the first and second trimester of pregnancy, platelet count revealed apparent decrease or a tendency to decrease. But it trended to increase in the last trimester of pregnancy, and by puerperium it seemed to return to the normal.
2) The numbers of megakaryocytes generally increased during the course of maternity; the increase in megakaryocyte count seemed rather mild in the first trimester, but later this tendency was enhanced gradually and maximum megakaryocyte count was proved in puerperium. The platelet forming ability of each megakaryocytes was declined in the first and second trimester. But an increasing tendency of platelet forming ability of the megakaryocytes was seen by the last trimester and reached to normal by puerperium.
3) Platelet count and megakaryocytes picture of women, who were undergone artificial abortion in early period of pregnancy, showed a tendency to return to normal to compare with that of unoperated subjects, but it seemed rather weak than that expected in puerperium. The returing in platelet count and megakaryocytes picture following the artificial abortion performed during the latter half of term was markedly enhanced, and nearly the same to that of puerperium, to compare with that expected in subjects operated during the former half of term.
4) It is inferred, therefore, from the results of this study that the thrombocytopenia developed in the course of pregnancy is due to, at least in a part, the decreased platelet forming ability of megakaryocytes.
5) It is also suspected that the functional abnormality of megakaryocytes seems to originate from the development of chorionic gonadotropin in pregnant women.