The Follicular Phase

The Follicular phase is the first phase of the menstrual cycle. The phase lasts about 2 weeks or 1-14 days in this cycle. During this period the follicles in the ovaries mature and continue to mature until the point of ovulation. This phase can be charted by the beginning of a woman’s menstrual cycle, or the first day of bleeding. A lot happens during this phase after the menstrual cycle and there a few hormones that play major roles to make it all happen.

Hormones Involved

Estradiol is the main hormone during the Follicular phase and the increased levels of estrogen stimulate the production of GnRH which also increases the production of LH. As the LH amount increases a LH-Surge happens right before ovulation. But to get there, the estrogen stimulates the lining of the uterus to thicken it allowing the amount of estrogen to rise until it triggers the surge. Once the surge is done and over with, the menstrual cycle moves into the ovulation phase and out of the Follicular phase.