[Age at menarche of students in Vojvodina].

By the status quo method the age of menarche was investigated in 15,235 girls, aged 10.5 to 17.5 years, from 35 places in the Socialist Autonomous Province of Vojvodina. Menarche was recorded in 8,188 (53.74%) girls. It proved to appear (the median obtained by the probit analysis) at the age of 12.68 +/- 0.01 years, i. e. at that age 50% of girls had menarche. The confidence limits were 12.63 and 12.70 years. The age of menarche in relation to parents' profession showed no significant differences between different occupations. The highest difference was observed between daughters of fathers-intellectuals (12.56 years) and mothers-intellectuals (12,60 years) on the one hand and daughters of fathers-peasants (13.05 years) and mothers-housewives (12.87 years) on the other. According to monthly income per household member, the earliest menarche (12.59 years) was found in girls with the highest income (over 2500 Dinars) and the latest (12.90 years) in those with the lowest income (below 1500 Dinars), the difference not being statistically significant.