[Menarche in Bulgarian--secular trend in twenty century]

The aim of the study was to determine the time of menarche in Bulgarian girls and specify the changes in menarcheal age during 20 century.

We examined in a longitudinal study 93 girls from 3 schools in Sofia in the period from 1994-2000.

Mean age of menarche in girls was 11.96 + 0.75 years, (x + SD), median 12, 00 years. At the age of eleven 41.9% of the investigated girls have already had menarche and at the age of 10--4.3%. By the completion of the 12 years 90.3% were with menarche and at 14 years of age--100%. In a study in Bulgaria, done by the beginning of 20 century (1904-1906), the mean age of menarche was 15.0 + 3.32 years, 3 years later than it was found by us at the end of the century.

We observed a secular trend of earlier time of menarche in Bulgarian girls during 20th century.