Follicular phase menstruation refers to the first phase of the menstrual cycle in women. The menstrual cycle is a regular sequence of hormonal changes that occur in the female reproductive system, preparing the body for potential pregnancy each month. The follicular phase marks the beginning of this cycle.
During the follicular phase, the primary focus is the development of ovarian follicles, which house the immature eggs. The hypothalamus, a region of the brain, releases a hormone called gonadotropin-releasing hormone (GnRH), which stimulates the pituitary gland to release follicle-stimulating hormone (FSH). FSH then prompts several ovarian follicles to start maturing. As these follicles grow, they release the hormone estrogen into the bloodstream.
Estrogen has various effects on the body, such as stimulating the thickening of the uterine lining (endometrium) to prepare for potential implantation of a fertilized egg. At the same time, the increased estrogen levels also suppress the release of FSH, causing only one dominant follicle to continue maturing, while the others undergo a process of regression.
The follicular phase typically lasts for about 14 days, but can vary in duration among individuals. It is followed by the ovulation phase, during which the mature follicle bursts, releasing the egg for possible fertilization. If fertilization does not occur, the menstrual phase begins, leading to the shedding of the uterine lining and the start of a new menstrual cycle.
