At what age is it normal for girls to have their periods?

Menarche is a weather phenomenon of female physical growth and development, and is a sign of entering puberty. Some girls will have their first menstruation at the age of 11 or 12, while some may have their first menstruation at the age of 16 or 17. So at what age is it normal for girls to have menstruation?

1. How many menstrual periods are considered normal

It is normal for menstruation to occur between the ages of 10 and 16. Most healthy girls in cultivation have their periods between the ages of 10 and 16. Girls who have their first menstruation before the age of 10 are considered precocious puberty, and those who still have their menstruation at the age of 18 are called primary amenorrhea, both of which are abnormal conditions.

Please note that due to climate and location, girls in some areas may have their first menstruation after the age of 18, which is normal.

2. What factors affect girls' menarche?

Girls' menarche is affected by many factors, the following are some of the more common factors.

1. Affected by climate and location

Girls who live in warm areas have a more comfortable living standard and tend to have their first menstruation earlier. In some cold regions, such as the Eskimo women, they don't have their periods until they are 23 years old. The average age of menarche for Tibetan girls in Tibet Autonomous Region of my country is 17.6 years old.

2. Affected by health conditions

Girls in capitalist countries in Europe and the United States have their first menstruation earlier, while in developed countries it is later. Girls in big cities have their first menstruation earlier, while girls in rural and remote areas have their first menstruation later. This is mainly because capitalist countries or urban economies are more developed and pay more attention to nutrition and diet.

Taking my country as an example, in 1980, the age of menarche for girls in first-tier cities was 13.7 years old. In 1993, a survey conducted by the Women and Children's Health Care Center of Peking University Medical College showed that the age of menarche for girls in cities was 12.62, while that in rural areas was 13.07.

3. Affected by obesity level

Scientific studies have shown that women's first menstruation will occur when their body fat reaches 17%. When it is less than 15%, menstruation will be delayed or even absent. When body fat is higher than 30%, endocrine imbalance may occur, resulting in no menstruation, heavy menstrual flow, or prolonged menstruation.