The Timing of Human Menarche

Abstract

<p>Like other aspects of female physiology, menarche is senstlive to aspects of the spcial and physical environment. Two surveys, involving 1,314 Ontario residents, were distributed to examine the relationship between family composition and the timing of human menarche. The average menarcheal age was 13.00 years and is concordent with previous estimates for central Canada. Menarche occurred most frequently in the spring and summer months and occurred later in women born ofter 1960 than in those born prior to this date. Most socioeconomic factors did not significantly influence the timing of menarche, but weight per height was marginally and negatively correlated with menarcheal age. Total score on a life events inventory, a measure of stress, was negatively and significantly correlated with the age at menarche. Menarcheal age was positively related to the age at which a girl began dating. The most striking finding was that girls who experienced father absence before menarche matured on average 4.5 months earlier than girls who lived with both parents continuously. Moreover, girls who had experienced father absence before ten years of age and because of divorce matured 5-6 months earlier than girls growing up with both parents. Absence of the mother and number of brothers end sisters did not appear to be related to the timing of menarche. A significant correlation existed between mothers' and daughters' ages at menarche. The mothers of father-absent girls tended to be early maturers, dated early, had early first births and reported more negative views of men than did the mothers of father-present girls. Heredity and psychological stress may largely account for the early age at menarche observed in father--absent girls, but physical exposure to a father and other psychological factors could elso be involved.</p>