The objective of this study was to establish the serum IGF-1 level in newborn infants, and investigate its association with growth and diseases.

In a retrospective study, serum IGF-1 levels were measured for newborn infants admitted to NICU at Kyungpook University Hospital from March 2007 to July 2007. Birth data, disease history, and hospital course were obtained from medical records.

Of 52 blood samples obtained at birth, serum IGF-l levels in 30 preterm infants (31.6±27.3 ng/mL) were lower than in 22 full-term infants (53.4±40.0 ng/mL; P <0.05). In sick full-term infants, serum IGF-1 levels (46.0±40.2 ng/mL) were lower than in healthy full-term infants (64.1±39.5 ng/mL; P <0.05). In preterm infants, there were no differences in IGF-1 levels between healthy (33.2±23.3 ng/mL) and sick infants (30.6±30.4 ng/mL); however, IGF-1 levels in both sick and healthy preterm infants were lower than in healthy full-term infants. Among infants admitted after 8 days of life, serum IGF-1 levels were higher in infants who gained weight (70.8±36.2 ng/mL) than in infants who lost weight (13.3±19.9 ng/mL; P <0.01); however IGF-1 levels showed no difference between gender or method of delivery.

The study showed lower IGF-l levels in preterm infants than in full-term infants. Additionally, the IGF-l level in infants with weight loss was lower than in infants with weight gain. These results indicate that serum IGF-1 is associated with gestational age and postnatal growth.