Comparison of postnatal catch-up growth according to definitions of small for gestational age infants

Abstract

PurposeSmall for gestational age (SGA) is confusingly defined as birth weight (BW) either below 3rd percentile or 10th percentile for infants. This study aimed to compare postnatal catch-up growth between SGA groups according to different definitions.MethodsData of 129 infants born with BW below the 10th percentile and admitted to Korea University Anam Hospital and Ansan Hospital were retrospectively reviewed. Height and weight were measured at 6, 12, and 24 months. Results were compared between group A (BW: <3rd percentile) and group B (BW: 3rd–10th percentile).ResultsGroup A included 66 infants and group B included 63. At age 6 months (n=122), 62.9% of group A and 71.7% (P=0.303) of group B showed catch-up growth in weight. At 6 months (n=69), 55.9% of group A and 80.0% of group B (P<0.05) showed catch-up growth in height. At 12 months (n=106), 58.5% of group A, and 75.5% (P=0.062) of group B showed catch-up growth in weight. At 12 months (n=75), 52.8% of group A and 64.1% of group B (P=0.320) showed catch-up growth in height. Up to age 24 months, 66.7%/80.0% in group A and 63.6%/80.0% in group B showed catch-up growth in weight/height.ConclusionDespite different definitions, there were no significant differences between the two SGA groups in postnatal catch-up growth up to age 24 months, except for height at 6 months. Compared to infants with appropriate catch-up growth, low gestational age and BW were risk factors for failed catch-up growth at 6 months.

Eligibility for growth hormone therapy in children born small for gestational age is substantially lower than expected

“…31 Karlberg et al concluded that the vast majority (>86%) of 'healthy' full-term SGA infants will achieve ACUG already during the first 6-12 months of life, but about 50% remain short at (near) adult height. 11,32 In the present study, we also found that most children who achieve ACUG do so within the first 2 years of life (84.8% for height more than −2.5 SD and 80.5% for height more than −2 SD). This pattern may reflect the gradual diminishing effect of the intrauterine environment and the expression of the genetically programmed height.…”

“…As to the rate of achieving ACUG, most previous studies reported only 85%‐90% of spontaneous ACUG in SGA infants during the first 2 years of life 31 . Karlberg et al concluded that the vast majority (>86%) of ‘healthy’ full‐term SGA infants will achieve ACUG already during the first 6‐12 months of life, but about 50% remain short at (near) adult height 11,32 . In the present study, we also found that most children who achieve ACUG do so within the first 2 years of life (84.8% for height more than −2.5 SD and 80.5% for height more than −2 SD).…”

Factors Associated with Catch-up Growth in Term, Asymmetrical Small-for-Gestational Age Infants in the First Year of Life

“…Previous studies have shown that CUG is not influenced by antenatal factors. 12,13 The association found in our study may be attributed to the severity of antenatal medical conditions and other confounding factors such as maternal age, pregnancy weight gain, or parity, although no significance was noted via multivariate analysis.…”

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

“…This difference between studies might be due to different definitions. 26 Studies have used weight, body length, and head circumference for evaluation, with catch-up growth defined as an increase in the corresponding physical index Z scores by >0.67. 14 Full-term SGA infants tend to have rapid catch-up growth after birth.…”