Follicular Phase

**Definition:** The period of the MENSTRUAL CYCLE representing follicular growth, increase in ovarian estrogen (ESTROGENS) production, and epithelial proliferation of the ENDOMETRIUM. Follicular phase begins with the onset of MENSTRUATION and ends with OVULATION.

**Tree numbers:** - G08.686.605.310

**Synonyms:** - Menstrual Cycle, Follicular Phase - Preovulatory Phase - Menstrual Proliferative Phase - Menstrual Cycle, Proliferative Phase