Urinary ß2-microglobulin in very preterm neonates with chorioamnionitis.

It is important to identify premature infants with prenatal inflammation as it contributes to short- and long-term complications. Our object was to study how prenatal inflammation affects the urinary β(2)-microglobulin (β(2)-MG) level. Preterm neonates were divided based on the presence of chorioamnionitis (CAM) into the CAM (n = 100) and non-CAM groups (n = 117). These were further subdivided into five groups each: 30 preterm neonates of 23-26; 42 neonates of 27-28; 54 neonates of 29-30; 51 neonates of 31-32; and 40 neonates of 33-34 weeks' gestation. The urinary β(2)-MG level within 48 h of birth was significantly higher in the CAM group than in the non-CAM group among the neonates of 23-26 weeks' gestation (18.3 ± 6.9 vs 10.0 ± 5.6 × 10(4) μg/gCr, p = 0.0018) and the neonates of 27-28 weeks' gestation (16.2 ± 10.8 vs 8.8 ± 3.3 × 10(4) μg/gCr, p = 0.0101). However, there was no difference in urinary β(2)-MG level between the CAM and the non-CAM group among the neonates ≥ 29 weeks 'gestation. Moreover, the elevated urinary β(2)-MG level in the neonates ≤ 28 weeks ' gestation with CAM had disappeared by 1 week after birth. The reasons for the increase in urinary β(2)-MG level within 48 h of birth in very preterm neonates (≤ 28 weeks' gestation) with CAM are believed to be not only prematurity, but also prenatal inflammation. It is suggested that the urinary β(2)-MG level during the early postnatal period can identify prenatal inflammation.