| Menstrual cycle | |||||
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The menstrual cycle is a part of the female reproductive cycle that only females experience.
The menstrual cycle is the body of a woman's way of preparing for a possible pregnancy. The menstrual cycle happens once every 28 days (approximately) - although the cycle can vary anywhere from 23-35 days and still be considered to be normal and healthy.
In the first half of the menstrual cycle, the following occurs:
- oestrogen levels rise and the lining of the uterus starts to thicken
- the anterior pituitary gland releases follicle stimulating hormone (FSH) which causes an egg from one of ovaries to mature, preparing for release.
- around day 14 (the middle of the cycle) leutinising hormone is secreted which causes the mature egg to be released from the ovary - which is termed ovulation
In the second half of the menstrual cycle, the following occurs:
- the mature egg travels down the fallopian tubes and into the uterus
- progesterone levels rise, which aid the uterine walls for possible pregnancy
- if a sperm cells fertilises the egg at this time, and the fertilised egg attached to the uterus cell wall, the woman becomes pregnant
- if there is no sperm cell to fertilise the egg, it is either absorbed into the body or is dissolved
- if pregnancy does not happen, the levels of both the hormones eostrogen and progesterone steadily fall
- the uterine wall is shed during menstruation, which occurs at approximately day 28
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Important menstrual cycle facts
- The menstrual cycle is the way the body prepares for pregnancy
- Menstruation is just part of the menstrual cycle
- The menstrual cycle lasts from anywhere between 23-35 days
- Many hormones are released during the menstrual cycle anda disruption of these can cause health probelms
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Why the menstrual cycle is important
Women who are approaching menopause (in perimenopause) can experience an irregular menstrual cycle and thus irregular menstruation. Young girls who have just started menstruating also experience an irregular menstrual cycle too.
The menstrual cycle is necessary to enable pregnancy to occur.
references
- Marieb EM, Hoehn K. Human Anatomy & Physiology. 7th edition, 2006. Benjamin Cummings Publishing
- Tortora GJ, Derrickson BH. Principles of Anatomy & Physiology. 11th edition, 2005. Wiley Publishing
To learn more, go to the the following web sites:
- Monash University - Menstrual Chart (Australia)
- Family Planning Australia
- University of NSW (Australia)
- Sexual Health Information Network & Education (Australia)
- Feminist Women's Health Centre (USA)
