Girls experience menarche at different ages. The timing of menarche is influenced by female biology as well as genetic and environmental factors , especially nutritional factors. The average age of menarche has declined over the last century but the magnitude of the decline and the factors responsible remain subjects of contention. The average age of menarche is 11.75 years.
Menarche is the culmination of a series of physiological and anatomic processes of puberty :
- Attainment of a sufficient body mass ( typically 20 % body fat).
- Dis inhibition of the GnRH pulse generator in the arcuate nucleus of the hypothalamus.
- Secretion of oestrogen by the ovaries in response to pitutary hormone.
- Over an interval of about 2 to 3 years, estrogen stimulates growth of the uterus (as well as height growth, breast growth, widening of the pelvis , and increased regional adipose tissue).
- Estrogen stimulates growth and vascularity of the endometrium , the lining of the uterus.
- Fluctuations of hormone levels can result in changes of adequacy of blood supply to parts of the endometrium.
- Death of some of the endometrial tissue from these hormone or blood supply fluctuations leads to deciduation, a sloughing of part of the lining with some blood flow from the vagina .
A specific hormonal signal for menarche is not known; menarche as a discrete event is thought to be the relatively chance result of the gradual thickening of the endometrium induced by rising but fluctuating pubertal estrogen.
The menstration , or "flow," consists of a combination of fresh and clotted blood with endometrial tissue. The initial flow of menarche is usually brighter red than mature menstrual flow. It is often scanty in amount and may be very brief, even a single instance of "spotting." Like other menses, menarche may be accompanied by abdominal cramping .
In most girls, menarche does not signal that ovulation has occurred. In postmenarchal girls, about 80% of the cycles were anovulatory in the first year after menarche, 50% in the third and 10% in the sixth year. Regular ovulation is usually indicated by predictable and consistent intervals between menses, predictable and consistent durations of menses, and predictable and consistent patterns of flow (e.g., heaviness or cramping). Continuing ovulation typically requires a body fat content of at least 22%. An anthropological term for this state of potential fertility is nubility .
On the other hand, not every girl follows the typical pattern, and some girls ovulate before the first menstruation. Although unlikely, it is possible for a girl who has engaged in sexual intercourse shortly before her menarche to conceive and become pregnant , which would delay her menarche until after the birth. This goes against the widely held assumption that a woman cannot become pregnant until after menarche.
When menarche occurs, it confirms that the girl has had a gradual oestrogen -induced growth of the uterus , especially the endometrium , and that the "outflow tract" from the uterus, through the cervix to the vagina , is open.
In very rare instances, menarche may occur at an unusually early age, preceding thelarche and other signs of puberty. This is termed isolated premature menarche, but other causes of bleeding must be investigated and excluded. Growth is usually normal. Isolated premature menarche is rarely the first manifestation of precocious puberty .
When menarche has failed to occur for more than 3 years after thelarche, or beyond 16 years of age, the delay is referred to as primary amenorrhea.
Some of the least understood environmental influences on timing of puberty are social and psychological. Nearly all of the research on these effects has concerned girls, partly because female puberty requires greater physiological resources and partly because it involves a unique event (menarche) that makes survey research into female puberty much simpler than male. In most of these studies menarche was specifically examined, assuming it to be a valid "proxy" for the more general process of puberty.
In comparison with the effects of genetics, nutrition, and general health, social influences are small, shifting timing by a few months rather than years. The most important part of a child's psychosocial environment is the family., hence at public place such happening must not be repeated., take precautions.
|SAY " NO" FOR NEXT TIME|
Some of the aspects of family structure and function reported to be independently associated with earlier menarche:
- The increased incidence of childhood obesity (both estrogen and progesterone molecules are derived from cholesterol).
- Absence of father from the home from early childhood
- High-conflict family relationships
- Had a low birth weight
- Are singletons
- Are non-white
- Were exposed to smoking
- Were not breast-fed
- Lacked exercise in childhood
Some of the aspects of family structure and function reported to be independently associated with later menarche:
- Larger family size.
- Warmer, closer or more positive relationship with biological father.
- Warmer, more supportive, low-stress family environment
- Have a number of older siblings
The understanding of these environmental effects is incomplete and the following observations and cautions are relevant:
- Mechanisms of these social effects are unknown, though a variety of physiological processes.
The main anxiety to a young girl is a new thing , and worrying thing is to whom she should tell. I think the young girls must never hide the natural process from Mother.
Mother after taking the daughter in confidence , should explain everything in details , so that the girl will develope confidence and will welcome this natural phenomenon ., and do not come in the Non sense talks of friends. If at all She has a query ., Mother must give liberty to solve her queries , with a very peace and without any kind of pressure.