What characterizes the luteal phase of the ovarian cycle?

The luteal phase of the ovarian cycle is characterized by the period that follows ovulation, which occurs around the midpoint of the menstrual cycle. Specifically, it typically lasts about 14 days, ending with the start of menstruation if fertilization does not occur. During this phase, the ruptured follicle transforms into the corpus luteum, which secretes hormones like progesterone that are crucial for preparing the uterine lining for a potential implantation of a fertilized egg.

The significance of this phase lies in its role in maintaining the uterine environment favorable for pregnancy. Should fertilization happen, the corpus luteum is maintained by hormones from the developing placenta; otherwise, it degenerates, leading to a drop in hormone levels and the onset of menstruation.

For clarity, the other phases and events of the menstrual cycle, such as the follicular phase (the first 14 days) or menstruation itself, do not define the luteal phase. The days of ovulation denote the moment an egg is released from the ovary but do not characterize the subsequent luteal phase, which is concerned with the actions that take place afterward. This understanding is key to grasping female reproductive physiology in the context of the ovarian cycle.