Menarche 2-2 rural malnour twin culture
Menarche
Globally the
average age has declined
due to better
health care, nutrition
. D
Influenced by genetics, environment specially nutrition. D
Between 13 and 14. D
12.5 in United States. 12.7 in Canada. 12.9 in UK. D
Similar age as their mother.
Assam 13.2 d
Twin sisters within 2 months
and non identical twins 20 months apart.
Great role of genetics
possible. D
Polygenic
inheritance. D
Climate variation not. Nigeria and eskimo girls 14.4 despite
different climates. Assam and European girls 13.2 d
India 12.8 v and 13.8. Singapore 12.4 and 14.4
v. Nutrition has effect. D
Tripathi 1987. Delhi 11.2 Calcutta 12.5 12.8 Gujarat 14.8. d
urban girls earlier
than rural. D
in the
first year 80% cycles are non ovulatory. 10% in sixth year.
Therefore 5 to 6 years after menarche chances of fertility rise. D
earl
y menarche associated with risk of breast cancer and endometrial cancer which may be related to estrogen
. D
Culturally
at used to mark the beginning of
womanhood
but today in many societies 18 years of age is considered the womanhood. D