Influence of perinatal factors on the onset of puberty in boys and girls: implications for interpretation of link with risk of long term diseases.

The authors examined the hypothesis that perinatal factors influence the onset of puberty. Children born as singletons in Uppsala, Sweden, in 1973-1977 were followed for height development before and during their school years (through 16 years of age). In all, 62 children born after preeclampsia, 129 born prematurely, 90 born small for gestational age, 175 born large for gestational age, 49 born short for gestational age, and 38 born tall for gestational age were compared with 688 "normal" children. Differences in age and height at puberty onset and age at menarche were analyzed using the t test and analyses of covariance. For boys, the mean age at puberty onset did not differ between normal boys and those with perinatal factors. Boys born small or short for gestational age were 4 cm shorter than normal boys, and those born large for gestational age were 3 cm taller than normal boys. Among girls, patterns for differences in height were similar. Girls born small for gestational age were 5 months younger than normal girls at the onset of puberty and menarche. Patterns of early childhood growth seemed to explain the relations between these perinatal factors and height and age at puberty. The authors conclude that body size at birth affects stature at puberty; in girls, smallness for gestational age is associated with earlier puberty. Associations between intrauterine exposures and disease risk may be confounded by, or mediated through, effects on adolescence.