The Menarche Age And Its Changing Tendency For 30 Years For The 4 Groups Of Girls In Huhhot

Menarche is one important indicator of sexual maturity for adolescent girls. With the long-term acceleration in growth of girls, the menarche age is also constantly moving up. At present, there is a lot of relevant research documentation at home and abroad. In China, there still exists a tendency of constant moving up of the menarche age of girls whereas there are few reports on whether the tendency of constant moving up of the menarche age is still going on in the various regions or whether the menarche age tends to be stable. This article was written after the author investigated 4666 cases of menarche age in 4 groups of people (urban Mongolian ethnic group, rural Mongolian ethnic group, urban Han ethnic group, and rural Han ethnic group) in Huhhot, inner Mongolia, in December 2002. It has conducted research on the long-term variation tendency of menarche age of the female on the basis of year of birth and year of menarche. Furthermore, it has given an analysis of the month and age distribution of menarche for the menstruating women in the 4 groups under the current investigation.Result: (1) In terms of menarche age, the menarche age of the girls in Huhhot is mainly concentrated,at the age of 12-13 with the youngest at 8 and the oldest at 17. (2) On the basis of grouping as per the year of birth, the general variation tendency is that the menarche age of the 4 groups of females born in 1963-1992 in Huhhot has been moving up. However, for nearly 10 years after 1993, the speed of moving up has greatly decreased (urban Mongolian ethnic group at 2. 52 months as per the Status quo method and 0. 60 month as per the Retrospective method, rural Mongolian ethnic group at 6.12 months as per the Status quo method and 1.80 month as per the Retrospectivemethod, urban Han ethnic group at 2.40 months as per the Status quo method and 3. 00 month as per the Retrospective method, and rural Han ethnic group at 0.96 months as per the Status quo method and 2.88 month as per the Retrospective method). That indicates the ceasing of the tendency of moving up of menarche age and the tendency of gradual concentration of menarche age of the 4 groups. (3) On the basis of grouping as per the menarche year, the general tendency is that the menarche age of the 4 groups of menstruating females in 1979-2002 has been moving up. However, since 1988, the speed of moving up for each decade has been as follows: only 2. 60 months for urban Han ethnic group, 2.40 months for rural Han ethnic group, 0.90 month for urban Mongolian ethnic group, and 0, 20 month for rural Mongolian ethnic group. That indicates the ceasing of the tendency of moving up. Furthermore, of the menarche groups of 2000-2002, the menarche age of the 4 groups tends to be the same. (4) The monthly distribution of menarche of the 4 groups of females in Huhhot has shown the features of double-peaks with the highest frequency in summer. (5) As a result of statistical analysis of the data contained in this article by the Status quo method, it is indicated that the menarche age of the urban Mongolian ethnic group, rural Mongolian ethnic group and urban Han ethnic group in Huhhot is earlier than the average level in the large cities in China and that of the local rural Han ethnic group is earlier than the average level in the fairly well-off rural areas in our country. In conclusion, the menarche age of females in Huhhot may have reached the lower limit of genetic control and the menarche age has shown a stable tendency.