What are the two phases of the menstrual cycle?

The menstrual cycle is primarily divided into two main phases: the follicular phase and the luteal phase.

During the follicular phase, which begins on the first day of menstruation, the ovaries prepare to release an egg. This phase is characterized by the maturation of follicles in the ovaries under the influence of follicle-stimulating hormone (FSH). The increase in estrogen levels from these developing follicles leads to the thickening of the uterine lining in preparation for potential implantation.

Following ovulation, which occurs at the end of the follicular phase, the luteal phase begins. During this time, the ruptured follicle transforms into the corpus luteum, which secretes progesterone. This hormone is crucial for maintaining the uterine lining, should fertilization occur. If fertilization does not happen, the corpus luteum degenerates, leading to a drop in hormone levels, triggering the onset of menstruation and the cycle begins again.

Other choices refer to specific phases or events within the broader menstrual cycle but do not encapsulate the cycle as a whole in the same way. The proliferative and secretory phases are parts of the endometrial cycle, corresponding with the follicular and luteal phases of the ovarian cycle,