Analysis of longitudinal follow-up data of physical growth in singleton full-term small for gestational age infants

Objective This study aimed to investigate the catch-up growth pattern of singleton full-term small for gestational age (SGA) infants in the first year after birth. Methods A single-center retrospective cohort study was performed to assess singleton full-term SGA infants. Weight, length, and head circumference were measured at birth, and at 1, 3, 6, and 12 months of age. Results Two hundred ten SGA infants were included in this study. Boys (n = 90) and girls (n = 120) showed a similar gestational age, birth weight, and body length. Weight, length, and head circumference in SGA infants in all age groups increased with age, with the fastest growth stage from birth to 3 months. The speed of weight and head circumference catch-up was higher than that of body length. At 12 months, significant associations of height in boys with height of the fathers, mothers, and both parents combined appeared. The height of girls showed associations with the mothers' and the parents' height. Conclusions Full-term SGA infants grow rapidly after birth, with the fastest growth rate in the first 3 months, as examined by weight, body length, and head circumference. However, the catch-up speed of weight and body length were not balanced in this study.