CRP and ileus: Those infants receiving antibiotics > 3 days had later median age of NEC onset (18.0 [9.25;34.0] vs. 5.00 [4.00;19.0]; p = 0.002), higher median CRP on the day of NEC onset (2.60 [1.10;6.00] vs. 0.70 [0.50;1.10]; p = 0.003) and longer post operative ileus days 16 days [12.5;21.0] vs. 7 days [7.00;12.0]; p = 0.021) compared those receiving antibiotics = < 3days.