title: [Age of menarche. Secondary sex characteristics. Interrelation. Secular trend].
abstract: Our purpose was to determine the mean age of menarche in young females of our population. To relate menarche with maturation stages of secondary sex character. To observe if the secular trend persist after the first observation. Consistently two temporal observations spaciated for 10 years were performed. Two hundred and eighty three healthy women who belonged to a higher middle-level and attending a high school from Cordoba National University were studied. Such women were in an age range between 11.0 to 18.0 years. Anthropometric and biological maturation examination were undertaken (Tanner). The mean age of onset of secondary sex characters was determined in a longitudinal follow-up group (54 girls). The mean age of menarche in the overall sample was determined by the retrospective method and in the subsample of 54 girls longitudinally followed in the 70-80 decade was determined by the prospective method in which the menarche was correlated with stages of mamary development (B) an pubic hair (PH). The mean age of menarche in 146 young females with a follow-up from 1.981 through 1.990 was determined. In the overall sample the mean of age of menarche was of 12.59 years +/- 1.17; in the subsample (54 girls) of 12.75 years +/- 1.03. In this subsample 70.37% of them has the menses in the B3 stage, 22.22% in B4, 5,5% in B2 and 1.85% in B5. 74.07% PH3, 18.51% in PH4, 0.52% in PH2 and none in PH5. In the sample of 146 young females with a follow-up between 1981 and 1990 the mean age of menarche was 12.36 years. If this result is compared with that of the 54 girls longitudinally followed in the prior decade and with the overall sample, a difference of 0.39 years and 0.23 years respectively is proved. This difference favoring an earlier age of menarche would show: 1 degree) That in our environment the secular trend is maintained, the age advances 4 months every 10 years and 2 degree) That the longitudinal prospective method is more reliable than the retrospective one.
authors.affiliation: Cátedra de Pediatría y Neonatologia, U.N.C.
authors.forename: S M
authors.initials: SM
authors.lastname: Zurlo de Mirotti
authors.forename: A M
authors.initials: AM
authors.lastname: Lesa
authors.forename: M
authors.initials: M
authors.lastname: Barrón de Carbonetti
mesh_terms: D000293:Adolescent; D000328:Adult; D000367:Age Factors; D001118:Argentina; D001824:Body Constitution; D002648:Child; D005260:Female; D006801:Humans; D008572:Menarche; D011446:Prospective Studies; D012044:Regression Analysis; D012494:Sampling Studies; D012727:Sex Characteristics; D012959:Socioeconomic Factors
vernacular_title: Edad de menarca. Caracteres sexuales secundarios. Interrelacion. Tendencia secular.