Menarche signifies beginning of Menstruation in a female.
Age at Menarche is always asked or whenever a woman goes for Gynecological or obstetrical
Understanding Menarche would entail understanding MENSTRUATION
WHAT IS MENSTRUATION?
Menstruation is the cyclical shedding of the inner lining
of the uterus that manifests as periodic bleeding from the vagina occurring throughout a
womans reproductive life. First menstruation for a girl (menarche) signals
the onset of her reproductive life that usually ends with menopause (stoppage of the
A menstrual period generally lasts from
three to seven (4-5) days. An average of about 100 ml of blood is lost. Menstruation also
ceases during pregnancy and often during breastfeeding.
During the first years of menstruation
may be irregular, but most women eventually establish a regular pattern. It is common for
intervals to be as brief as 21 days or as long as 45. Some women never become entirely
regular, but this does not affect their health. Irregularity is also common in the older
woman just before menopause.
A woman of any age needs a physical examination when her
irregularity is more than slight, as when there are many months between periods.
WHAT HAPPENS DURING MENSTRUATION?
The uterine wall is made up of two layers, first a
muscular layer myometrium (comprises almost 99% of the uterine wall) and the
endometrium - inner thin layer of cells, to which the foetus gets attached during
pregnancy. Accordingly, every month the endometrium has to be prepared to accept the
embryo. This happens through a series of hormonal fluctuations.
In order to understand what exactly happens, lets
understand the hormonal changes.
The hypothalamus, which is situated in the brain,
controls all the hormones of the body. In this case hypothalamus releases a hormone
that called as gonadotropin-releasing hormone in turn acts on the pituitary gland which in
turn releases hormones acting on the Thyroid gland. Hormones produced by the thyroid gland
ultimately act on the ovary to produce oestrogen and progesterone - the female sex
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Without going into intricacies let us remember that there
is more of oestrogen in the first half of the cycle whereas there is more of progesterone
in the latter half.
Physiology of Menstruation