RESUMO
Menopause, cessation of menstruation, is a public event for all women that occur between the ages of 45-55 [or even sooner]. A variety of researches done in Iran and the rest of the world show age at menopause can depend on numerous factors such as race and genetics, socioeconomics, history of fertility, physical activity, nutrition, sexual behaviors, diseases and etc. However, there are inconsistencies between results from different researches which can be related to methodology and methods of analysis. Present research has been done to analyze methodologies which estimate age at natural menopause and its associated factors by considering their power and weakness points. The cohort and cross-sectional methodologies to estimate age at natural menopause are introduced as well as appropriate statistical techniques to determine effective factors. Iranian and the some foreign papers, which their main object or one of the principle objects was estimating age at menopause, are introduced and analyzed. The results show that prediction and estimation of age at menopause are more complicated than it seems. Nearly all Iranian and some foreign surveys are poor in methodology and methods of analysis which decreases the efficacy and correctness of their findings