The Optimal Postnatal Growth Trajectory for Term Small for Gestational Age Babies: A Prospective Cohort Study

ObjectivesTo identify an optimal growth trajectory for term small for gestational age (SGA) babies from birth to 7-years-old.Study designData were from the Collaborative Perinatal Project, a US multicenter prospective cohort study from 1959-1976. Five weight growth trajectories of the 1957 term SGA babies were grouped by a latent class model. We selected the optimal growth pattern based on the lowest overall risks of childhood diseases.ResultsCompared with appropriate for gestational age children, SGA babies with no catch-up growth (439, 22.4%) had higher risks of infection in infancy (aOR 1.2, 95% CI 1.0-1.6), growth restriction (11.2, 8.6-14.6), and low IQ (2.1, 1.7-2.8) at age 7 years. Those with excessive catch-up growth (176, 8.9%) had higher risks of overweight/obesity (7.5, 5.4-10.5) and elevated blood pressure (1.7, 1.1-2.4) at age 7 years. Babies with slow catch-up growth (328, 16.8%) or regression after 4 months (285, 14.6%) were associated with higher risks of low IQ (1.6, 1.2-2.1) and growth restriction (2.2, 1.5-3.2), respectively. Only babies with appropriate catch-up growth (729, 37.3%) did not have increased risk of adverse outcomes. Further, we also tested linear growth trajectories with similar findings.ConclusionsThe optimal growth trajectory for term SGA infants may be fast catch-up growth to about the 30th percentile in the first several months, with modest catch-up growth thereafter, to be around the 50th percentile by 7-years-old.