Classification of newborns by birth weight according to the use of conventional customized curves (CCs) and new CCs (new CCs). SGACC or SGANEW CC, small for gestational age according to the use of conventional curves (CCs) or new, customized curves (new CCs), respectively). SGACConly by: Infants classified as SGA according to the CCs and as AGA according to the new CCs. SGANew CConly by: Infants classified as SGA according to the new CCs and AGA according to the CCs. OR1: Odds ratio of SGACConly by, SGANEW CConly by, and SGAby both CC versus AGAby both CC for the composite outcome 1 (cesarean section, Apgar < 7 at 1st min, Apgar < 7 at 5th min, NICU admission or mortality). OR2: Odds ratio of SGACConly by, SGANew CConly by, and SGAby both CC versus AGAby both CC for composite outcome 2 (Apgar < 7 at 1st min, Apgar < 7 at 5th min, NICU admission or mortality).* p value < 0.05 and *** p value < 0.001.