Growth and sexual maturation of low birth weight infants at early adolescence.

OBJECTIVE To assess the growth and sexual maturity of non-handicapped children with birth weight less than 2000 g at 12 years. DESIGN Prospective cohort study. SETTING Infants discharged from a Neonatal Special Care Unit of a referral hospital with birth weight less than 2000 g between 1987-1989 and followed up till the age of 12 years. METHODS The height, weight and head circumference was measured. Sexual maturity was determined by Tanners score and age of menarche in girls was reported by parents. Parental height and weight was recorded. Intelligence quotient was determined by Weschslers Intelligence Scale. RESULTS The cohort of 180 low birth weight (LBW) infants (birth weight less than 2000 g) was divided into 3 groups according to their gestation - preterm SGA (n=73), full term SGA (n=33) and preterm AGA (n=74). Ninety full term AGA infants served as controls. Preterm SGA children had significantly less height (mean deficit 5.8 cm), weight and head circumference (P<0.001). There was no significant difference in sexual maturity and onset of menarche between the study group and controls. There was a correlation between head circumference and IQ and preterm SGA children had the lowest mean IQ (85.4 +/- 17.7). Mothers height contributed 14% variance to a total variance of 25.3% for Z score of height at 12 years. Mothers weight contributed a variance 21.1% to a total variance of 29.4% for Z score of weight. CONCLUSION Preterm SGA children were shorter, lighter and had the smallest head circumference, and also had the lowest IQ. Mothers height and weight was an important determinant of height and weight at 12 years.