Follicular phase

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Follicular phase
Figure 1. Menstrual cycle illustrating hormone levels, follicle development and uterine cycle
Biological system	Urogenital system(reproductive)

The follicular phase, also known as the preovulatory phase or proliferative phase,^[1] is the phase of the estrous cycle (or, in primates^[2] for example, the menstrual cycle) during which follicles in the ovary mature from primary follicle to a fully mature graafian follicle. It ends with ovulation. The main hormones controlling this stage are secretion of gonadotropin-releasing hormones, which are follicle-stimulating hormones and luteinising hormones. They are released by pulsatile secretion.^[1] The duration of the follicular phase can differ depending on the length of the menstrual cycle, while the luteal phase is usually stable, does not really change and lasts 14 days.