Polyploidy in the human myometrium.

In an investigation to determine whether the enlargement of cells and nuclei in the myometrium of the human uterus during pregnancy is related to the development of polyploidy or not, the following facts were established, mainly on the basis of cytophotometric analysis of nuclei isolated with a newly developed mechanical technique from a series of uteri in different states with regard to the reproductive process (juvenile, nulligravida, gravida, sectio parva, sectio caesarea). 1. Polyploid nuclei arise only during pregnancy. They can still be found for many years after the puerperium; their occurrence, however, remains a discrete phenomenon. 2. During pregnancy, a swelling of virtually all diploid nuclei is observed, which is present as early as 16 weeks after conception, but a significant increase of the nuclear projection area is found only in the Caesarean section group. This swelling, which (might occur under hormonal influence is possibly of a functional nature and is separate from the development of polyploidy as such. 3. By means of the tracing of double sex chromatin bodies in the nuclei, the occurrence of tetraploid nuclei in the myometrium could be demonstrated both in nuclear suspensions and in sections of intact uterine wall.