Histology of the human corpus luteum of early and late pregnancy.

The aim of this investigation has been to examine which histological parameters are of value in the age determination of the corpus luteum of pregnancy. The material comprises representative ovarian biopsies from 16 women from the 10th through 42nd week of gestation. The following histological parameters have been found useful for the age determination of the corpus luteum: 1) the size of the granulosa cells; 2) the number of K-cells, vacuoles and colloid inclusions in the granulosa cell layer; 3) the size of the theca interna cells; (4) the size of the vessels in the theca interna. Futhermore, the differentiation of the corpus luteum of pregnancy from the corpus luteum of menstruation is described, and some indications for a histological age determination of the corpus luteum of pregnancy are mentioned.