Objective Information on outcome by gestational age fromlarge numbers of twins and triplets i s limited and is im-portant for counseling and decision-making in obstetric practice.We reviewed one of the larg est available neonatal databases to describe mortality and morbidity rates and growth in newborn infants from multiple gestations and compared these data with data for sin gletons.Study design Data from a large prospectively recorded neonatal database that incorporated neonatal records from January 1997to July 2002were reviewed.We evaluate d birth weight and neonatal mortality and morbidity ra tes that affected long -term outcome for each week of gestational age from 23to35weeks of gestation for all nonanom olous inborn twins and triplets who were admitted to the neonatal intensive care unit and compared these data to all singletons who met similar criteria during the same tim e period.Results Therewere 12,302twin and 2155triplet bir ths that met the entry criteria.The data for these newborn infants were compared with 36,931singletons.Average bir th weights at each gestational week were similar for all gestational ages until29weeks of gestation for triplets an d 32weeks of gestation for twins.After these gestational ages,the entire difference between twins and singletons was due to the weight of the smaller twin;the larger twins’mean weights were similar to singletons at all weeks that were s tudied.Birth order at each week also did not affect neonata l mortality rates,even when corrected for route of delivery and antenatal steroids.Neonatal morbidities associated wi th adverse long -term outcomes(intraventricular hemorrhage,reti nopathy of prematurity,necrotizing enteroco litis)were also not dif-ferent between multiple infants and singletons.Intrauterine growth restriction(IUGR)was associated with increased mortality rates at all gestational ages,but in the absences of IUGR,discordance was not.Conclusion Data on a large number of twins and triplets provide reassurance that neonatal outcome at all viable prema ture weeks of gestation are similar to singletons.Intraute rine growth restriction and prematurity are therefore the principal issues that drive neonatalmortality andmorbidity ra tes in multiple gestations.These data are important for obstetr ic decision -making and patient counseling. Objective Information on outcome by gestational age fromlarge numbers of twins and triplets is limited and is im-portant for counseling and decision-making in obstetric practice.We reviewed one and the neonatal databases to describe mortality and morbidity rates and growth in newborn infants from multiple gestations and compared these data with data for sin gletons.Study design Data from a large prospectively recorded neonatal database that incorporated neonatal records from January 1997to July 2002were reviewed.We evaluate d birth weight and neonatal mortality and morbidity ra tes that affected long -term outcome for each week of gestational age from 23to35weeks of gestation for all nonanom olous inborn twins and triplets who were admitted to the neonatal intensive care unit and compared these data to all singletons who met similar criteria during the same tim e period. Results Therewere 12,302twin and 2155triplet bir ths that met the entry criteria. The data for thes a newborn infants were compared with 36,931singletons.Average bir th weights at each gestational week were similar for all gestational ages until29weeks of gestation for triplets an d 32weeks of gestation for twins. After this gestational ages, the entire difference between twins and singletons was due to the weight of the smaller twin; the larger twins’mean weights were similar to singletons at all weeks that were s tudied.Birth order at each week also did not affect neonatal mortality rates, even when corrected for route of delivery and antenatal steroids .Neonatal morbidities associated wi th adverse long -term outcomes (intraventricular hemorrhage, reti nopathy of prematurity, necrotizing enteroco litis) also also dif-ferent between multiple infants and singletons.Intrauterine growth restriction (IUGR) was associated with increased mortality rates at all gestational ages, but in the absences of IUGR, discordance was not. Confidence Data on a large number of twins and triplets provide reassurance that neonatal outcome at all viable prema ture weeks of gestation are similar to singletons.Intraute rine growth restriction and prematurity are therefore the principal issue that drive neonatalmortality andmorbidity ra tes in multiple gestations .sese data are important for obstetr ic decision -making and patient counseling