Effects of Antenatal Steroid on Postnatal Fluid Balance in Very Low Birth Weight (VLBW) Infants during the First Week of Life

ABSTRACT

PURPOSE: Antenatal steroid (AS) may result in lower insensible water loss (IWL), and higher urine output (UO) in early life. We examined if the postnatal fluid balance differed between infants exposed to AS or not (control) in VLBW infants. METHODS: Fifty-four VLBW infants were grouped into AS (n=24) or control (n=30). Fluid intake, UO, IWL and maximal % of weight loss on day 1, day 2, day 3 and day 7 after birth were analyzed. Daily maintenance fluid was determined in each infants by calculation of insensible water loss (IWL=[intake-output]-Delta wt) and UO. RESULTS: Fluid intake (AS vs control; 117.2+/-33.9 vs 126.0+/-29.6 mL/kg/d, P=0.315), IWL (28.1+/-23.7 vs 21.1+/-20.5 P=0.248), UO and maximal % of weight loss on day 7 were not different between groups similar findings were observed on day 1, day 2, and day 3 after birth. Neonatal morbidities and clinical relevant factors were not different between groups. The duration of assisted ventilation was shorter in the AS than in the control (10.8+/-9.2 vs 27.6+/-26.2, P=0.002). However, the difference disappeared after adjustment for RDS severity and oxygenation index. CONCLUSION: VLBW infants exposed to AS did not have an alteration in postnatal fluid balance during the first week of life, when given fluid based on needs reflected by IWL and UO. The decreased need for assisted ventilation in the AS group may be related to the effects of steroid on fetal lung fluid absorption or maturity, but not on postnatal fluid balance.