In Western countries with temperate climates and health-conscious lifestyles, girls usually reach puberty and menstruate around the ages of 12 to 14. Slight postponements can occur, but consultation is required if the first period occurs around age 9 or after age 16.
It also turns out that women who began menstruating before the age of 12 should think about having children sooner than their peers who mature a little later. A study conducted by Australian researchers on a group of 50,000 women from the UK, Australia, Japan and Scandinavia found that the age at which the menarche occurs correlates with the timing of the onset of menopause.
Among the participants of the study, the average age at which they had their first menstrual period was 13 years, while the last was 50 years. It turned out, however, that the subjects who entered puberty before the age of 12 had a 31% probability of early menopause and the end of the fertile period between the ages of 40 and 44.
Based on the discovery, the researchers recommended that women who started menstruating early in life should think ahead about expanding their family and not put off the decision to have children for too long.