Growth and sexual maturity pattern of girls with mental retardation

Background: Growth of mentally retarded children differs from that of normal children. However, the adolescent growth and development of Indian mentally retarded children has not been studied. Aim: This study was conducted to evaluate the physical growth and sexual development of adolescent mentally retarded girls in North Indian population and to compare it with that of normal girls of same age group. Materials and Methods: One hundred mentally retarded (intelligence quotient (IQ) less than 70) and 100 normal girls between 10 and 20 years of age were categorized into 1-year age groups. Their height was measured and the sexual development was assessed based on breast development (BD) and pubic hair growth (PH) stages 1-5 on the basis of Tanner scale. The data was then compared between the two groups using Student's t-test. The mean age of menarche was calculated by applying Probit analysis. Results: The mean height of mentally retarded girls was significantly retarded as compared to normal girls at all ages; however, the mean height gain during 11-20 years was same in both the groups. The mentally retarded girls also showed significant retardation in PH growth at 15-17 years and in BD at 15-16 years of age. Conclusions: The physical growth and sexual development of adolescent mentally retarded girls was retarded as compared to the normal girls. The physical growth retardation occurred during early childhood (before 11 years), however the retardation in sexual maturity occurred during middle adolescence, between 15-17 years of age.