Endocrinology

Approximately eight days into the follicular phase, FSH levels decrease due to negative feedback at the level of the pituitary gland and estradiol levels increase due to previous stimulation by FSH at the level of the ovary.

 Follicular Development

Primary unilaminar continue to develop into primary multilaminar follicles. With increased estrogen production, the follicles form fluid-filled vesicles which can later mature into an antrum.

 Uterine Endometrial Cycle

The late follicular phase is marked by proliferation of the functionalis and proliferation and elongation of non-secreting endometrial glans.