Introduction Small for gestational age (SGA) is defined as infants with a birth weight below the 10th percentile for gestational age. However, this definition does not differentiate SGA infants who are constitutionally small from those who are growth-restricted (FGR). The risk of mortality and morbidity is increased in infants with FGR. Ponderal index (PI) is a useful tool to detect FGR. Therefore, it is important to define PI of SGA infants and we aimed to determine the PI of SGA term infants born in our hospital.

Material and methods This study included 3187 newborns who were born at or after 37 weeks’ of gestation at American Hospital, Istanbul, Turkey. Infants whose birth weight was below 10^th percentile according to the growth curve of Turkish neonates were considered as SGA infants. PI of SGA infants were calculated according to the formula; [weight (in g) x 100] ÷ [length (in cm)]³. PI of SGA infants were plotted on the PI – gestational age curve. Statistical analyses were performed by SPSS 17.0.

Results There were 107 (3.36%) SGA infants. 62 (57.9%) of them were female, and 45 (42.1%) of them were male. PI was in normal ranges (between 10–90p) in 85% (10–90p). In 7 neonates (6.5%) PI was above 90 p. In 8 neonates (7.5%) PI was below 3–10p and only 1 neonate (%0.9) had PI below 3p. None of them had severe morbidity or died. There was no correlation between PI and gestational age (spearman; r=0.027, p=0.78).

Conclusion With normal growth, the PI increases gradually from 30 to 37 weeks gestation and then remains constant which is a finding compatible with our study as we also observed no correlation between PI and gestational age in this study. Only 9 SGA infants (8.4%) had fetal malnutrition among whom only one of them had severe wasting with no morbidity and mortality. It may be reasonable to evaluate only SGA infants with PI less than 10 p.