Epidemiologic survey of menstrual patterns amongst adolescents in Nigeria.

Nine hundred and fifty secondary school girls aged between 10 and 18 years were randomly selected and surveyed. Information on their age at menarche, regularity of menstruation at onset and the time of survey and length of period of irregularity were sought using a well structured questionnaire. Estimation of blood loss per period premenstrual symptoms and signs, prevalence and severity of dysmenorrhoea were also inquired about. This study demonstrated a secular trend in the age at menarche when compared with other similar studies conducted in the previous decade in Nigeria. A higher prevalence of 71.8% of any grade of dysmenorrhoea was found in this study when compared with figures from developed countries, this and the short mean duration of irregular menstruation (3.7 months after menarche) were taken to be evidence of early establishment of regular ovular menstruation.