A woman has reached menopause when her ovaries stop releasing eggs (ovulating). Because bleeding does not come every month as menopause approaches, a woman is considered no longer fertile once she has gone 12 months in a row without having any bleeding.
Menopause usually occurs between the ages of 45 and 55. About half of women reach menopause by age 50. By age 55 some 96% of women have reached menopause.
To prevent pregnancy until it is clear that she is no longer fertile, an older woman can use any method, if she has no medical condition that limits its use. By itself, age does not restrict a woman from using any contraceptive method.