Menstruation, often referred to as a period, is a natural process involving vaginal bleeding that occurs as a regular part of a woman’s monthly cycle. Each month, the body gets ready for a potential pregnancy. When pregnancy doesn’t happen, the lining of the uterus, or womb, is shed. The menstrual blood consists of both blood and tissue from the inside of the uterus, which exits the body through the vagina.
Menstruation, often referred to as a period, is a natural process involving vaginal bleeding that occurs as a regular part of a woman’s monthly cycle. Each month, the body gets ready for a potential pregnancy. When pregnancy doesn’t happen, the lining of the uterus, or womb, is shed. The menstrual blood consists of both blood and tissue from the inside of the uterus, which exits the body through the vagina.
The menstrual cycle is a natural process that occurs in the female reproductive system, typically lasting about 28 days, though it can range from 21 to 35 days. It involves a series of changes in the ovaries and the lining of the uterus (endometrium) to prepare the body for a possible pregnancy.
Phases of the Menstrual Cycle
- Menstrual Phase (Day 1-5):
- This is when menstruation occurs, where the lining of the uterus is shed through the vagina, resulting in bleeding. This phase marks the beginning of the cycle.
- Hormones: Low levels of estrogen and progesterone.
Follicular Phase (Day 1-13):
- This phase starts with menstruation and continues until ovulation. During this time, the pituitary gland releases follicle-stimulating hormone (FSH), which prompts the ovaries to produce approximately 5 to 20 follicles. Each follicle houses an immature egg, but typically, only one will fully mature.
- The endometrium starts to thicken in anticipation of a possible pregnancy.
- Hormones: Rising levels of estrogen.
- Ovulation (Day 14):
- The mature egg is expelled from the ovary and travels into the fallopian tube.
- This is the most fertile period of the cycle and usually occurs around the midpoint of the cycle.
- The luteinizing hormone (LH) surges, triggering ovulation.
- Hormones: Peak levels of estrogen, LH surge.
- Luteal Phase (Day 15-28):
- After ovulation, the empty follicle transforms into the corpus luteum, which secretes progesterone to maintain the thickened lining of the uterus in case of pregnancy.
- If the egg is not fertilized, the corpus luteum breaks down, leading to a drop in progesterone and estrogen levels, triggering the menstrual phase to begin again.
- Hormones: High levels of progesterone initially, decrease if pregnancy does not occur.
Key Hormones Involved:
- Estrogen: Promotes the thickening of the endometrium.
- Progesterone: Stabilizes the endometrium and prepares it for possible implantation of an embryo.
- Follicle-stimulating hormone (FSH) promotes the development of ovarian follicles..
- Luteinizing Hormone (LH): Triggers ovulation and development of the corpus luteum.
Signs and Symptoms:
- Menstrual Phase: Cramps, bloating, breast tenderness, mood swings.
- Follicular Phase: Energy levels often increase, the skin may clear up, and some women feel more vibrant.
- Ovulation: Some may experience mild pelvic pain (mittelschmerz), increased libido, and clear cervical mucus.
- Luteal Phase: Symptoms of premenstrual syndrome (PMS) may occur, including mood changes, fatigue, and bloating.
Menstrual Irregularities:
- Amenorrhea: Absence of menstruation.
- Dysmenorrhea: Painful periods.
- Menorrhagia: Heavy menstrual bleeding.
- Oligomenorrhea: Infrequent menstruation.
Understanding the menstrual cycle is crucial for reproductive health, family planning, and managing any related health concerns.