Menarche 2-2 rural malnour twin culture
average age has declined
due to better
health care, nutrition
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
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
first year 80% cycles are non ovulatory. 10% in sixth year.
Therefore 5 to 6 years after menarche chances of fertility rise. D
y menarche associated with risk of breast cancer and endometrial cancer which may be related to estrogen
at used to mark the beginning of
but today in many societies 18 years of age is considered the womanhood. D