Abstract
Background Menarche is an important event in a female's reproductive health. However, the age at menarche is variable and has implications on the future health of the girl. The purpose of this study was to estimate the mean age at menarche of North Indian adolescent girls and its association with the Tanner stage and to study the trend of menarcheal age in India in the 21st century. Materials & methods A longitudinal descriptive study was conducted on 470 healthy girls aged nine to 16 years in expectant menarche (Tanner stage II). They were followed for six months to check for the attainment of menarche. Those who achieved menarche were grouped in Group I and the rest in Group II. The data were analyzed using the independent t-test. Results Menarche was achieved by 263 girls in the six-month follow-up period. The mean (SD) age of menarche was 13.13 (1.23) years. Group I girls were mostly in Tanner stage IV and above. Group II girls had a mean (SD) age of 11.53 (1.1) years and were mostly in Tanner stage III or below. The estimated decline in the age of menarche in the 21st century was about 0.41 years per decade. Conclusion The girls who achieved menarche had a significantly higher age and Tanner stage of sexual maturity than girls who did not achieve menarche in the study period. Tanner stage is a better measure to estimate the pubertal onset than age. The studies on the age of menarche in the current century reveal that the declining trend in the menarcheal age is continuing in India.