Postnatal growth of 724 (423 premature, 301 full-term) small for gesta
tional age infants (SGA, birth length less than the third length perce
ntile (P3) for gestational age) was studied for the first 2 y of life.
The study group consisted of all SGA infants who had been admitted ov
er a period of 8 y at the Departments of Neonatology of three Universi
ty Hospitals in The Netherlands with exclusion of infants with well de
fined causes for growth retardation, such as chromosomal disorders, sy
ndromes, severe malformations, or complications during the neonatal pe
riod or later on. The aim of the study was to describe postnatal growt
h of SGA infants and to find predictive factors for catch-up growth gr
eater than or equal to P3 during the first 2 y of life. The majority (
around 85%) of the healthy SGA infants showed catch-up growth to a hei
ght greater than or equal to P3 during the first 2 y of life. The perc
entage of premature SGA infants with catch-up growth greater than or e
qual to P3 at 2 y of age (82.5%) was not significantly different from
that of full-term SGA infants (87.5%). Birth length SDS was more sensi
tive than birth weight SDS in predicting catch-up greater than or equa
l to P3 in premature SGA infants. In contrast, birth weight SDS was th
e best predictor for catch-up greater than or equal to P3 in full-term
SGA infants. Gestational age, multiple birth, and sex were not signif
icantly associated with catch-up in height greater than or equal to P3
. For children with a length still below P3 at 3 or 6 mo of age, the a
ctual length SDS at that age appeared positively associated with catch
-up greater than or equal to P3. In SGA premature infants there was al
so a positive association between the weight gain during the first 6 m
o and the catch-up growth greater than or equal to P3. SGA children wi
th short stature (height <P3) at 2 y of age need further investigation
.