Infants Born Late Preterm: Epidemiology, Trends, and Morbidity Risk

Late preterm infants, defined as infants delivered from 34 through 36 completed weeks’ gestation, are less mature developmentally and physiologically than term infants (37 to 41 completed weeks’ gestation). Such immaturity places infants born late preterm at higher risk of morbidity and mortality than term infants during infancy and potentially throughout life. The purpose of this article is to review the epidemiology of infants born late preterm by describing the frequency of late preterm births; trends over time; and differences according to maternal age, race, and ethnicity. In addition, the article describes limitations associated with accurate estimation of gestational age and explains how these limitations may affect understanding of the true frequency of late preterm birth. Finally, the evidence of neonatal, postneonatal, and childhood morbidity risk associated with being born late preterm is compared with that of infants born at term.

[1]  Gabriel J Escobar,et al.  Increased risk of adverse neurological development for late preterm infants. , 2009, The Journal of pediatrics.

[2]  C. Hall,et al.  Persistence of Morbidity and Cost Differences Between Late-Preterm and Term Infants During the First Year of Life , 2009, Pediatrics.

[3]  M. Kramer.  Late preterm birth: appreciable risks, rising incidence. , 2009, The Journal of pediatrics.

[4]  A. Hjern,et al.  Perinatal complications and socio-economic differences in cerebral palsy in Sweden – a national cohort study , 2008, BMC pediatrics.

[5]  C. Ananth,et al.  Characterizing risk profiles of infants who are delivered at late preterm gestations: does it matter? , 2008, American journal of obstetrics and gynecology.

[6]  J. Gould,et al.  School outcomes of late preterm infants: special needs and challenges for infants born at 32 to 36 weeks gestation. , 2008, The Journal of pediatrics.

[7]  W. Callaghan,et al.  The relationship between cesarean delivery and gestational age among US singleton births. , 2008, Clinics in perinatology.

[8]  W. Engle,et al.  Late preterm infants, early term infants, and timing of elective deliveries. , 2008, Clinics in perinatology.

[9]  W. Barth,et al.  Late-Preterm Birth: Does the Changing Obstetric Paradigm Alter the Epidemiology of Respiratory Complications? , 2008, Obstetrics and gynecology.

[10]  E. Declercq,et al.  Effect of Late-Preterm Birth and Maternal Medical Conditions on Newborn Morbidity Risk , 2008, Pediatrics.

[11]  C. Berg,et al.  Variation between last-menstrual-period and clinical estimates of gestational age in vital records. , 2007, American journal of epidemiology.

[12]  K. Leveno,et al.  Neonatal Mortality and Morbidity Rates in Late Preterm Births Compared With Births at Term , 2006, Obstetrics and gynecology.

[13]  W. Engle,et al.  “Late-Preterm” Infants: A Population at Risk , 2007, Pediatrics.

[14]  C. Shapiro-Mendoza,et al.  Differences in mortality between late-preterm and term singleton infants in the United States, 1995-2002. , 2007, The Journal of pediatrics.

[15]  W. Callaghan,et al.  Trends in Preterm-Related Infant Mortality by Race and Ethnicity, United States, 1999–2004 , 2007, International journal of health services : planning, administration, evaluation.

[16]  U. Reddy,et al.  Infertility, assisted reproductive technology, and adverse pregnancy outcomes: executive summary of a National Institute of Child Health and Human Development workshop. , 2007, Obstetrics and gynecology.

[17]  I. Adams-Chapman.  Neurodevelopmental outcome of the late preterm infant. , 2006, Clinics in perinatology.

[18]  W. Callaghan,et al.  The Contribution of Preterm Birth to Infant Mortality Rates in the United States , 2006, Pediatrics.

[19]  M. Hedegaard,et al.  Gestational Age and Birth Weight in Relation to School Performance of 10-Year-Old Children: A Follow-up Study of Children Born After 32 Completed Weeks , 2006, Pediatrics.

[20]  G. Escobar,et al.  Unstudied infants: outcomes of moderately premature infants in the neonatal intensive care unit , 2006, Archives of Disease in Childhood - Fetal and Neonatal Edition.

[21]  Stephen R. Evans,et al.  Risk factors for neonatal morbidity and mortality among "healthy," late preterm newborns. , 2006, Seminars in perinatology.

[22]  E. Declercq,et al.  Early discharge among late preterm and term newborns and risk of neonatal morbidity. , 2006, Seminars in perinatology.

[23]  Eve Blair,et al.  Epidemiology of cerebral palsy. , 2006, Seminars in fetal & neonatal medicine.

[24]  B. Sibai.  Preeclampsia as a cause of preterm and late preterm (near-term) births. , 2006, Seminars in perinatology.

[25]  G. Hankins,et al.  The role of stillbirth prevention and late preterm (near-term) births. , 2006, Seminars in perinatology.

[26]  Siobhan M. Dolan,et al.  Changes in the gestational age distribution among U.S. singleton births: impact on rates of late preterm birth, 1992 to 2002. , 2006, Seminars in perinatology.

[27]  K. Joseph,et al.  Trends in twin preterm birth subtypes in the United States, 1989 through 2000: impact on perinatal mortality. , 2005, American journal of obstetrics and gynecology.

[28]  K. Joseph,et al.  Trends in Preterm Birth and Perinatal Mortality Among Singletons: United States, 1989 Through 2000 , 2005, Obstetrics and gynecology.

[29]  G. Escobar,et al.  Rehospitalisation after birth hospitalisation: patterns among infants of all gestations , 2005, Archives of Disease in Childhood.

[30]  H. Thaler,et al.  First- and second-trimester ultrasound assessment of gestational age. , 2004, American journal of obstetrics and gynecology.

[31]  Marvin L. Wang,et al.  Clinical outcomes of near-term infants. , 2004, Pediatrics.

[32]  T. Nesbitt,et al.  The Cost of Prematurity: Quantification by Gestational Age and Birth Weight , 2003, Obstetrics and gynecology.

[33]  Deren Bader,et al.  US birth weight/gestational age-specific neonatal mortality: 1995-1997 rates for whites, hispanics, and blacks. , 2003, Pediatrics.

[34]  M. Kramer,et al.  The impact of the increasing number of multiple births on the rates of preterm birth and low birthweight: an international study. , 2002, American journal of public health.

[35]  K. Joseph,et al.  Obstetric intervention, stillbirth, and preterm birth. , 2002, Seminars in perinatology.

[36]  K. Joseph,et al.  Changes in stillbirth and infant mortality associated with increases in preterm birth among twins. , 2001, Pediatrics.

[37]  K. Joseph,et al.  Causes and Consequences of Recent Increases in Preterm Birth Among Twins , 2001, Obstetrics and gynecology.

[38]  P. Hope,et al.  Educational and behavioural problems in babies of 32–35 weeks gestation , 2001, Archives of disease in childhood. Fetal and neonatal edition.

[39]  M. Kramer,et al.  The contribution of mild and moderate preterm birth to infant mortality. Fetal and Infant Health Study Group of the Canadian Perinatal Surveillance System. , 2000, JAMA.

[40]  C. Makinson.  The health consequences of teenage fertility. , 1985, Family planning perspectives.