Ovarian follicules begins while the female fetus is in the uterus. In the fifth week of pregnancy, the fetus has an average of 450 to 1350 primordial germ cells in the ovary. Primitive germ cells undergo mitosis, and by the twentieth week of pregnancy, the female fetus has an average of 5 to 8 million germ cells. After mitosis is completed, germ cells undergo meiotic proliferation and arrest in meiotic prophase I, forming germ cell cysts. During the peripartum period, each germ disappears to form a primordial follicle containing an oocyte, a cell cyst, and a single layer of nutritive granulosa cells. The ovary is the most important part of the human reproductive mechanism and it is of great importance to understand the ovary better in this book we have written. I would like to thank my colleagues who contributed to the study.
