Correlation between month of menarche and month of birth.
The month of menarche and month of birth were studied in 47,218 women who were born during a period of 90 years between 1881 and 1970. Among those born prior to 1960, there was a tendency for menarche to occur more frequently at the month of birth. This coincidence was not, however, found among those born after 1960.
D036861:Delivery, Obstetric; D005260:Female; D006801:Humans; D007564:Japan; D008572:Menarche; D012621:Seasons