Extrauterine growth restriction in preterm infants of gestational age ≤32 weeks

Background: Extrauterine growth restriction (EUGR) in low-birthweight (LBW) infants affects their growth and developmental prognoses as well as their incidence of adult diseases. The aim of the present paper was to determine the frequency and contributing factors of EUGR in infants <= 32 weeks of gestational age. Methods: The subjects consisted of 416 infants from 22 facilities born between February and October 2002, whose gestational age was <= 32 weeks. For EUGR assessment, subjects whose body measurements in the 37-42 week postmenstrual age (PMA) period were below the 10th percentile of the standard normal distribution, were selected. Results: EUGR incidence rates for weight, length, and head circumference were 57%, 49%, and 6%. In appropriate-for-gestational-age infants, a negative correlation was found between number of gestational weeks and EUGR incidence rates for weight, length, and head circumference, but in small-for-gestational-age infants this was true only for head circumference. Lower gestational age and age in days to achieve complete feeding were among the shared factors contributing to EUGR incidence for weight, length, and head circumference. The significant factors for EUGR incidence for weight and length included whether the infant was small for gestational age, whether oxygen was administered at 36 weeks PMA, age in days at which breast-feeding was initiated, and age in days when the infant regained birthweight. Conclusions: The growth retardation of preterm LBW infants in the neonatal intensive care unit continues to pose challenges. Relevant factors other than gestational age include intrauterine growth restriction, severe chronic lung disease, and poor nutrition.