Association between weight changes the first postnatal week and bronchopulmonary dysplasia-free survival in infants born at 23-26 weeks of gestation.

This study aimed to assess the relationship between weight change during the first postnatal week and hospital outcomes among extremely premature infants. This observational 10-year cohort study enrolled infants born at 23-26 weeks' gestational age (GA). Infants were classified in two groups, « weight loss Within the Target» (WT), if maximal weight loss was between 5 and 15% of birthweight, and « weight loss Outside the Target» (OT), if it was < 5% or > 15%. The primary endpoint was survival without moderate-to-severe bronchopulmonary dysplasia (BPD) at 36 weeks' GA, assessed using a propensity score approach. Secondary analyses were carried out among 3 subgroups of weight changes, (< 5%, 5-15%, and > 15% of birthweight). Two hundred and forty-five infants [25.7 (24.8, 26.2) weeks, 780 (680, 880) g] were included: 112 (46%) in the WT group, and 133 (54%) in the OT group. Survival without moderate-to-severe BPD was 60% (67/112) in the WT group, vs 37% (49/133) in the OT group (aOR 1.90 [1.02-3.54]). Moderate-to-severe BPD was 24% in the WT group, vs 46% in the OT group (aOR 0.44 [0.20-0.94]). Secondary analyses found higher survival without moderate-to-severe BPD, and lower rate of moderate to severe BPD in the WT infants compared to infants with maximal weight loss < 5% (p < 0.01 each).

conclusionMaximal weight loss during the first postnatal week between 5 and 15% of birthweight is associated with higher odds of BPD-free survival in extremely premature infants. WHAT IS KNOWN: • A positive fluid balance the first postnatal days is associated with poor outcomes. • Weight variation allows to estimate fluid balance and to adjust daily fluid intake. WHAT IS NEW: • Half of infants born at 23-26 weeks'gestational age lose 5-15% of birthweight. • Weight loss of 5-15% of birthweight is associated with increased BPD-free survival.