Menstrual cycle

Menstrual cycle is the periodic discharge of blood and mucosal tissue from the uterus, occurring from puberty to menopause in a woman who is not pregnant.

Menstrual Cycle

Physiology

The menstrual cycle is a complex and essential physiological process that occurs in the female reproductive system, preparing the body for potential pregnancy. The cycle typically occurs in monthly intervals, lasting around 28 days, though it can vary between individuals. It involves hormonal fluctuations that lead to changes in the ovaries and the uterus, such as the maturation of an egg and the buildup and shedding of the uterine lining.

Phases of the Menstrual Cycle

The menstrual cycle can be divided into several distinct phases, which can be further categorized into two main parts: the ovarian cycle and the uterine cycle.

Ovarian Cycle

The ovarian cycle consists of three phases:

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Cervix with menstrual flow

1. Follicular phase: This phase begins on the first day of menstruation and lasts until ovulation. During the follicular phase, the pituitary gland releases follicle-stimulating hormone (FSH), which stimulates the growth of several ovarian follicles. These follicles contain immature eggs, and only one will usually mature and be released during ovulation.
2. Ovulation: Ovulation typically occurs around the midpoint of the menstrual cycle, around day 14 in a 28-day cycle. A surge in luteinizing hormone (LH) triggers the release of the mature egg from the dominant follicle. The egg then travels down the fallopian tube, where it can be fertilized by sperm.
3. Luteal phase: This phase begins after ovulation and lasts until the start of the next menstruation. The ruptured follicle transforms into the corpus luteum, which secretes progesterone and estrogen. These hormones prepare the uterus for a potential pregnancy by thickening the endometrial lining.

Uterine Cycle

Lining of Uterine Wall

The uterine cycle consists of three phases:

1. Menstruation: If the egg is not fertilized or does not implant in the uterine lining, hormonal levels drop, and the thickened endometrial lining is shed through the vagina. This process is known as menstruation, which typically lasts between 3 to 7 days.
2. Proliferative phase: This phase overlaps with the follicular phase of the ovarian cycle. As estrogen levels rise, the endometrial lining begins to regenerate and thicken in preparation for a potential pregnancy.
3. Secretory phase: Coinciding with the luteal phase of the ovarian cycle, the secretory phase is characterized by increased levels of progesterone, which further prepares the endometrial lining for potential implantation by increasing blood flow and nutrient supply.

Hormonal Regulation

The menstrual cycle is regulated by a complex interplay of hormones, including:

• Gonadotropin-releasing hormone (GnRH): Secreted by the hypothalamus, GnRH stimulates the pituitary gland to produce FSH and LH.
• Follicle-stimulating hormone (FSH): Produced by the pituitary gland, FSH stimulates the growth and development of ovarian follicles.
• Luteinizing hormone (LH): Also produced by the pituitary gland, LH triggers ovulation and the formation of the corpus luteum.
• Estrogen: Secreted by the developing follicles and later the corpus luteum, estrogen helps regulate the menstrual cycle and is responsible for the development and maintenance of female secondary sexual characteristics.
• Progesterone: Produced by the corpus luteum, progesterone prepares the uterus for pregnancy by thickening the endometrial lining and suppressing further ovulation.

Menstrual Cycle Irregularities and Disorders

Menstrual cycle irregularities and disorders can arise due to various factors, including hormonal imbalances, stress, or underlying medical conditions. Some common menstrual cycle irregularities and disorders include:

• Amenorrhea: The absence of menstruation for three or more consecutive months. Primary amenorrhea occurs when menstruation has not begun by age 15, while secondary amenorrhea refers to the cessation of menstruation in someone who has previously had regular periods.
• Dysmenorrhea: Painful menstruation, characterized by severe cramps and discomfort during the menstrual period.
• Menorrhagia: Abnormally heavy or prolonged menstrual bleeding, which can lead to anemia and disrupt daily activities.
• Oligomenorrhea: Infrequent menstrual periods, with cycles lasting longer than 35 days.
• Polycystic ovary syndrome (PCOS): A hormonal disorder characterized by the presence of multiple small cysts in the ovaries, irregular periods, and elevated levels of androgens, which can cause excessive hair growth and acne.

Menstrual Cycle and Fertility

A woman's fertility is closely tied to her menstrual cycle. Ovulation, which typically occurs around the midpoint of the cycle, represents the time when a woman is most fertile. Tracking ovulation and fertility awareness can be helpful for those trying to conceive or avoid pregnancy. Methods to track ovulation include monitoring basal body temperature, observing changes in cervical mucus, and using ovulation predictor kits.

Menstrual Hygiene and Health

Maintaining proper menstrual hygiene is essential for overall health and well-being. During menstruation, women should use sanitary products, such as pads, tampons, or menstrual cups, to manage menstrual flow. It is crucial to change these products regularly to prevent infection and maintain hygiene. Additionally, practicing good personal hygiene, such as bathing regularly and washing hands before and after changing sanitary products, is important.

Menstrual cycle Resources
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