Follicular Phase

Follicular Phase: the long phase constituting the first half of the human menstrual cycle. As the menstrual flow ceases, the ovarian follicle continues its development started at the end of the previous cycle and increases its production of inhibin B and estradiol. The endometrium is stimulated by increasing levels of estrogen and increases in thickness to prepare for possible reproduction. At the end of this phase the luteinizing hormone surge and follicle-stimulating hormone surge begin, signaling the start of the ovulatory phase.