Where do periods come from?

Menstrual periods are part of a natural process in women of reproductive age called the menstrual cycle. Here's how periods occur:

1. Menstrual Cycle: The menstrual cycle typically lasts around 28 days, although it can vary from person to person. It consists of two primary phases: the follicular phase and the luteal phase.

2. Follicular Phase: At the start of the menstrual cycle, the body prepares for the possibility of pregnancy. Estrogen levels rise, stimulating the growth and maturation of a follicle (a small sac containing an egg) in one of the ovaries. During this phase, the lining of the uterus also begins to thicken to create a suitable environment for implantation of a fertilized egg.

3. Ovulation: Approximately 14 days before the onset of the next period (in a typical 28-day cycle), a surge in luteinizing hormone (LH) causes the mature follicle to rupture and release an egg from the ovary into the fallopian tube. This process is known as ovulation.

4. Luteal Phase: After ovulation, the emptied follicle transforms into a corpus luteum, which produces progesterone and some estrogen. Progesterone and estrogen support the further thickening of the uterine lining in preparation for potential embryo implantation.

5. Menstrual Phase: If pregnancy does not occur, the corpus luteum begins to break down, leading to a decline in progesterone and estrogen levels. Without hormonal support, the thickened uterine lining sheds and is expelled from the body through the vagina, resulting in menstrual bleeding. This marks the start of a new menstrual cycle.

Note that the pattern and duration of menstrual cycles can vary among individuals, and periods may be influenced by hormonal factors, stress, lifestyle, and overall health. If you have any concerns or irregularities with your menstrual cycle, it's advisable to consult a healthcare professional.