Menstrual Cycle or Ovarian Cycle Or Female Reproductive Cycle

  • The menstrual (Latin: mensis means a lunar month) cycle is characteristics of primates (monkeys, apes and humans).  Menstruation is defined as the cyclic discharge of blood carrying broken tissue materials through the vagina. In a human female, the fertility period extends from the age of puberty, i.e. about 11-13 years up to menopause, i.e. 45-50 years. The onset of menstruation in a female is called menarche. It starts at an age of about 11-13 years. The permanent stoppage of menstruation in a female is called menopause. It occurs at an age of about 45-50 years. Between puberty and menopause, the female reproductive system passes through a regular monthly sequence of events called the menstrual cycle. Each menstrual cycle in humans lasts for 28 days. However, many times, due to some reasons this period may increase or
    The days are counted from the first day of blood flow in the menstrual period. A series of events occur regularly in females after every 26 to 30 days throughout the childbearing period i.e. from puberty to menopause.
  • The entire duration of a Menstrual cycle can be divided into four main phases:

Phases of Menstrual Cycle:

Menstrual phase (From day 1 to 5):

  • It is also called bleeding phase. The corpus luteum produces progesterone. During 14 days of ovulation, progesterone makes the lining of the uterus thick for implantation and is necessary to sustain a healthy pregnancy. When the ovum is not fertilized,  high level of progesterone inhibits secretion of luteinizing hormones (LH). This results in a decrease in the level of progesterone secreted by corpus luteum.
  • After 14 days of ovulation if the ovum is not fertilized the lining of the uterus starts degenerating and menstruation begins. The menstruation phase lasts for four to five days. The day when bleeding starts is considered to be the first day of menstrual cycle. The menstrual flow consists of the secretion of endometrial glands, cell debris (stripped off endometrium, mucus, leucocytes), blood and unfertilized ovum. During this phase, about 35 to 45  ml of blood is lost.

Menstrual cycle 01

  • When the amount of progesterone further decreases the anterior pituitary is stimulated to secrete follicle stimulating hormone (FSH) and the follicular or proliferation starts. At the end of menstruation, the thickness of endometrium becomes 0.5 to 1 mm.
  • Failure of menstruation cycle indicates pregnancy. But it should be confirmed medically. Because sometimes the failure of menstruation may be due to poor physical and mental stress or poor health.
  • The level of estrogen, follicle stimulating hormone (FSH), progesterone and Luteinizing hormone (LH) are minimum. Actually level of FSH decreases slightly during this period.

Follicular or Proliferation Phase (From day 1 to 13):

  • This phase also begins on the first day of menstruation, but it lasts until the 13th day of the menstrual cycle. The following events occur during this phase:
  • The pituitary gland secretes a hormone that stimulates the egg cells in the ovaries to grow.
  • One of these egg cells begins to mature in a sac-like-structure called follicle. It takes 13 days for the egg cell to reach maturity. During this period the primary follicle in the ovary grows into the fully mature Graffian follicle.
  • While the egg cell matures, its follicle secretes a hormone that stimulates the uterus to develop a lining of blood vessels and soft tissue called endometrium.

Menstrual cycle 02

  • The Graafian follicle also produces a hormone, estrogen, which stimulates the uterus to prepare itself to receive the ovum. Endometrium of uterine wall regenerates and ruptured blood vessels are repaired. The uterine glands grow. Thus it prepares the uterus for possible pregnancy. Hence follicular stage is also called proliferation state. By the end of this phase, the endometrium becomes 2 – 3 mm thick and endometrial glands become coiled and corkscrew shaped. The arterioles in uterine wall grow longer and branched making the wall highly vascular.
  • The level of estrogen starts increasing and it is maintained by follicle stimulating hormone (FSH) of the anterior pituitary. The level of FSH decreases initially but increases towards the ovulation. The level of progesterone remains almost constant. The level of Luteinizing hormone (LH) increases gradually.

Ovulation phase (Day 14):

  • On the 14th day of the cycle, the pituitary gland secretes a hormone that causes Graafian follicle to rupture and the ovary to release the matured egg cell. The released egg cell is swept into the fallopian tube by the cilia of the fimbriae. The cells of the ruptured Graafian follicle form the corpus luteum which secretes the hormone, progesterone.

Menstrual cycle 03

  • Levels of estrogen, FSH and LH are at their peaks. The peak level of LH at the mid of cycle (14 th day) is called LH surge. Which makes the Graffian follicle to rupture and release the ovum (egg).

Luteal phase or Secretory Phase (From day 15 to 28):

  • The period after ovulation is called luteal phase. This phase begins on the 15th day and lasts until the end of the cycle. The egg cell released during the ovulation phase stays in the fallopian tube for 24 hours (up to day 15 or  16). If a sperm cell does not fertilize the egg cell within that time, the egg cell disintegrates.
  • After shedding the ovum, the remaining part of the Graffian follicle is called corpus luteum (Latin: yellow body). The corpus luteum produces progesterone. Progesterone makes the lining of the uterus thick for implantation and is necessary to sustain a healthy pregnancy. The production of progesterone continues till the placenta begins to take over progesterone production. The corpus luteum formed is active in this period hence this phase is called luteal phase. Due to a high level of progesterone in this phase, this phase is also referred as progesterone phase. At the same time, nutritious fluid is secreted during this period hence this phase is also known as the secretory phase.
  • If the ovum is not fertilized: The progesterone that causes the uterus to retain its endometrium gets used up by the end of the menstrual cycle. This causes the menstrual phase of the next cycle to begin. At the end of the 28th day, this ovum is rejected along with the uterine lining. The corpus luteum regenerates and gets converted into fibrous tissue called corpus albicans (Latin: white body). This marks the start of a slow disintegration of the thickened lining of the uterus and the next menstrual cycle 

Menstrual cycle 04

  • If the ovum is fertilized: If the egg is fertilized, the corpus luteum starts receiving HCG(human chorionic gonadotropin) from the developing embryo. HCG instructs the corpus luteum to keep producing progesterone. Progesterone promotes further thickening of uterus up to 4 to 5 mm thick. endometrial glands become more coiled and more corkscrew shaped.  There is a secretion in the uterus from these glands which provides nourishment of dividing egg. The uterus is made ready for implantation. The higher progesterone inhibits further follicular maturation.

Irregular Menstrual Cycles:

  • When a girl begins menstruating, it may take some time for her periods to become regular. Most women have between 11 and 13 menstrual periods each year. Bleeding usually lasts around 5 days, but this too can vary, from 2 to 7 days. When menstruation first starts, it can take up to 2 years to establish a regular cycle (attaining the balance between estrogen and progesterone). However, for some female, the time between periods and the amount of bloodshed vary considerably. This irregularity is known as irregular menstruation.
  • The variation may be due to illness or mental tension such as stress or depression. The two hormones that impact menstruation are estrogen and progesterone.  sue to emotional condition the balance between them is not maintained.
  • Before menopause, women often have irregular periods, and the amount of bloodshed may vary.
  • Extreme weight loss, extreme weight gain, endurance physical activity, eating disorders may be other causes of irregular menstruation.

Hygiene  During the Menstrual Cycle (Period):

  • Daily bathing along with regular/daily washing of the genital area is essential. The vagina has its own cleaning mechanism which has a fine balance of good and bad bacteria. Use of soap can kill the good bacteria making way for infections. So use some warm water. Soap can be only used for external cleaning only and not the inner part.
  • Sanitary pads and/or cloths used should be changed at least twice a day, if not more frequently.
  • It is important to maintain menstrual hygiene in order to reduce the risk of contracting an infection of the female reproductive tract and urinary tract. To avoid infection the washing direction should be from the vagina to anus. opposite direction may cause infection.
  • If pads or napkins are not changed frequently, the old blood begins to smell. This may lead to social embarrassment.
    Home-made sanitary napkins should be washed thoroughly with hot water and soap and should be dried in a sunny and airy place. They should be stored in a clean and dry place.
  • When a female has periods, they should carry extra sanitary pads stored in a clean pouch or paper bag, a soft towel, some paper tissues or towels, hand sanitizer, a healthy snack, bottle of drinking water, a tube of antiseptic medication (if any).
  • Moderate exercise and sufficient rest are also important.

Development of Follicle During Period:

Menstrual cycle 06

Hormone Levels During Period:

Menstrual cycle 07

Uterian Wall During Period:

Menstrual cycle 08

Effect of Levels of Hormones:


  • Estrogens can be produced by fat tissue, the liver, the adrenal glands and the ovaries. The ovaries are the primary source of estrogens in premenopausal women, except for women who are pregnant. If they are normal and balanced by progesterone produced by corpus luteum a woman feels well.
  • There is a condition called estrogen dominance where too much estrogen is circulating in relation to progesterone. In such conditions following symptoms are observed in females. Irregular or otherwise abnormal menstrual periods, Headaches (especially premenstrually), Mood swings (most often irritability and depression)
  • Lower estrogen results in less vaginal lubrication, increase in urinary tract infections, irregular or missing of periods, headaches, attack of preexisting migraines, depression, fatigue and trouble in concentration. The causes of low estrogen are excessive exercises, eating disorders, low functioning pituitary gland, etc.


  • Progesterone is produced by corpus luteum in ovaries. It is responsible for making uterus ready for prospective pregnancy.
  • High level of progesterone results in weight fluctuations, drowsiness, depressed state ( not exactly depression),  dizziness, anxiety, feeling of tense, pain in legs. sleep inertia, etc.
  • Low level of progesterone results in headaches, migraines, mood changes, anxiety, depression, irregularity in periods.

Estrogen-Progesterone Balance:

  • Estrogen is balanced by progesterone. If it is not balanced estrogen may become the dominant hormone. This may lead to a variety of symptoms, including weight gain, mood swings, depression, heavy bleeding, irregular menstrual cycle, fibroids, gallbladder problems and thyroid dysfunction.


  • Menopause is the process through which a woman ceases to be fertile or menstruate. It is a normal part of life and is not a disease or a condition. It is a natural process in the body of any woman, but it causes drastic changes.
  • A diagnosis of menopause is confirmed when a woman has not had a menstrual period for one year.
  • The symptoms of approaching menopause are
    • irregular periods: (periods may shorten or lengthen),
    • Lower fertility: 3 to 5 years before menopause the estrogen level starts dropping. (Perimenopause stage). The lower level of estrogen decreases chances of pregnancy.
    • Vaginal dryness: Due to the low level of estrogen vaginal lubrication decreases. Which results in vaginal dryness, itching, and vaginal atrophy.
    • Hot flashes: These symptoms are shown in the first year of the final period. It is a sudden sensation of heat in the upper body. It may start in the face, neck, or chest, and progress upward or downward. It may make the skin red and patchy. The female start sweating, heart rate increases and irregular. These symptoms are mainly observed in the night during sleep cycles.
    • Insomnia:  Sleeps may be disturbed due to anxiety.
    • Urinary problems: There are possibilities of occurrence of urinary tract infections.
    • Emotional changes: Depression, mood swings may be observed. that may lead to disturbed sleep.
    • Low Concentration: short-term memory and difficulty in focusing.
    • Physical Change:  Accumulation of fat in abdominal region resulting in obesity, hair loss, breast shrinkage.

Possible Effects of Menopause:

  • Cardiovascular disease: (due to decrease in estrogen)
  • Osteoporosis: A decrease in bone density. Bones become brittle.
  • Urinary incontinence: frequent, sudden, and overwhelming urges to urinate. Women may involuntarily urinate after coughing, sneeze, laughing, or lifting during menopause.
  • Breast cancer:

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