Serum creatinine, blood urea nitrogen change in low birth weight infants during their first days of life

Kim, Shin Mi; Ko, Jeong Hee; Shim, Eun Jung; Lee, Dae Hyoung; Cho, Do Jun; Kim, Dug Ha; Min, Ki Sik; Yoo, Ki Yang

Abstract

OBJECTIVE
To study the changes in serum creatinine and correlation between gestational age or birth weight and serum creatinine in low birth weight infants in the immediate postnatal period.
METHODS
Medical records of all premature infants, who were admitted to the neonatal intensive care unit of Hallym University Hospital between January 2003 and December 2007, were reviewed. 162 infants met our inclusion criteria. Medical records were reviewed for : birth weight, gestational age, length, gender, APGAR scores, use of medications, blood urea nitrogen (BUN) and serum creatinine (Scr) during the first days of life. Premature infants were separated into three groups according to their birth weight: 500 to 999 g; 1,000 to 1,499 g; and 1,500 to 2,000 g.
RESULTS
Scr was found to decrease postnatally, however there was a delay in the decrease of Scr in the subgroup of infants<1,000 g BW, Scr was also found to decrease with increasing birth weight at 1 week after birth (Pearson test, p=0.01). Serum BUN was found to decrease with increasing birth weight at 1 week after birth (Pearson test, p=0.00).
CONCLUSION
In low birth weight infants Scr decrease during the first days of life. However, in infants smaller than 1,000 g birth weight there is a delay in the decrease of their Scr that extends beyond the first days of life. Our findings indicate progression of renal function is directly correlated to birth weight.