Prenatal use of indomethacin for preterm labor and renal function among very low birth weight infants.

Background: Indomethacin is administered as a tocolytic agent for threatening preterm labor <28weeks of gestation. Only a few, not conclusive, studies have investigated its nephrotoxicity in very low birth weight (VLBW) infants. We investigated whether indomethacin increases the incidence of acute kidney injury (AKI) among VLBW infants.

Methods: This is a retrospective study including all VLBW infants born at our center between January 1, 2005, and December 31, 2013. Indomethacin was administered to women with preterm labor and intact membranes. Neonatal AKI was defined according to KDIGO classification. Univariate analyses were performed comparing VLBW infants exposed to and not exposed to indomethacin. In the multivariable model, the association of indomethacin and AKI was adjusted for patent ductus arteriosus, use of nephrotoxic medications, birth weight, and gestational age.

Results: Five hundred seventy-five VLBW infants were included, 49 (8.5%) of whom were exposed to indomethacin in utero. The univariate analysis showed that infants exposed to indomethacin had lower birth weight, lower gestational age, and higher incidence of AKI than infants not exposed. The multivariable model adjusted for confounding factors confirmed an increased risk of AKI in relation to gestational age at birth <27 weeks, but not to indomethacin.

Conclusions: Our data suggest that extreme prematurity, but not the use of indomethacin, is associated with AKI.