ABSTRACT
The development of the oocyte is the key event in the follicular phase of the menstrual cycle. The ovary contains thousands of primordial follicles that are in a continuous state of development from birth, through periods of anovulation, such as pregnancy, to the menopause. These initial stages of follicular development are independent of hormonal stimulation. In the absence of the correct hormonal stimulus, however, follicular development fails at the pre-antral stage, with ensuing follicular atresia. Development beyond the pre-antral stage is stimulated by the pituitary hormones (luteinizing hormone [LH] and folliclestimulating hormone [FSH]), which can be considered as key regulators of oocyte development.
