Lck Low

Born small for gestational age: consequences for growth

A large number of studies have documented a strong correlation between size at birth and subsequent height, although the reported incidence of catch‐up growth and consequently the impact on final height has varied with time and between countries. These variations may be real, but could also be related to a number of methodological problems. The aim of this study was to explore two important aspects related to postnatal growth after disturbed fetal growth: first, the definition of small for gestational age (SGA), including the selection of cut‐off points in defining shortness; and, secondly, the importance of the general socio‐economic status of the population with regard to the incidence of growth faltering in early life. Data were analysed from two longitudinal population‐based studies, one from Sweden and one from Hong Kong. Of the Swedish cohort, 3.8% had a birth length below –2 SD scores; in the Hong Kong population the corresponding value was 11.9% (Swedish reference values were used in both studies). The following conclusions were made. Size at birth is important for postnatal growth, and the difference in length at birth of 9–10 cm between the two extreme birth length subgroups remains, on average, until maturity. This seems to be true for the two study populations with different degrees of socio‐economic development. However, the rate of catch‐up growth is highly dependent on the definition of SGA, on the rate of catch‐up growth in early life and on the incidence of growth faltering between 6 and 18 months of age.

Spontaneous growth in Chinese patients with Turner's syndrome and influence of karyotype

The pretreatment mixed cross‐sectional and longitudinal height measurements of 203 patients with Turners syndrome (TS) were analysed. Only one observation was included per year per child and a total of 858 observations formed the basis of the growth study. The mean and SD values were fitted separately by a second‐degree polynomial function, giving smoothed growth curves. The spontaneous growth pattern of Chinese girls with TS runs parallel to published Caucasian TS growth curves. The mean final height of Chinese patients with TS was 142 cm compared to 147 cm and 139 cm observed in Northern European and Japanese patients, respectively. Patients with the 46, X, i(Xq) karyotype were found to be significantly shorter, whereas children with the 45, X/46, XY and 46, X, del(Xq) karyotypes were significantly taller among this group of patients. Patients with TS who were disomic for Xp are significantly taller than patients who were monosomic for Xp. Our results suggest that karyotype can have a significant effect on the growth of children with TS.