Folikulaariset

Folikulaariset, also known as follicular phase, is the first phase of the menstrual cycle in women. It begins on the first day of menstruation and lasts approximately 14 days. During this phase, the follicle-stimulating hormone (FSH) stimulates the growth of follicles in the ovaries. One or two follicles typically dominate and begin to produce estrogen, which prepares the uterine lining for potential pregnancy. The dominant follicle continues to grow and eventually releases an egg, marking the onset of ovulation. The release of the egg is triggered by a surge in luteinizing hormone (LH), which also causes the remaining follicles to convert into the corpus luteum. The corpus luteum produces progesterone, which maintains the uterine lining and prepares the body for potential implantation of a fertilized egg. If fertilization does not occur, the corpus luteum degenerates, leading to a decrease in progesterone levels and the shedding of the uterine lining, resulting in menstruation and the start of a new menstrual cycle. The follicular phase is crucial for fertility, as it is during this phase that ovulation occurs and the uterine lining is prepared for potential implantation.