Outcomes of Preterm InfantMorbidity and Mortality in Late Preterm and Early Term Newborns: A Continuum
Section snippets
Definitions
Late preterm and early term newborns include infants that are categorized as infants born at 34 0/7 to 36 6/7 weeks’ gestation and 37 0/7 to 38 6/7 weeks’ gestation, respectively (Fig. 1). Late preterm was defined by participants at a 2005 workshop of the Eunice Kennedy Shriver National Institutes of Child Health and Human Development of the National Institutes of Health to address an emerging body of evidence that such infants had higher rates of morbidity and mortality than was generally
Magnitude of late preterm and early term births
The percentage of live births in the United States that were born late preterm increased between 1990 and 2006 from 7.3% to 9.14%, a 25% increase.11 This increase accounted for 84% of the increase in the rate of prematurity during that same 16-year period. During 2007 and 2008, the percentage of live births that were late preterm decreased by 3% to 8.77% of all live births (about 15,000 fewer late preterm births). Although this trend is encouraging, the percentage of live births born late
Acute Medical Morbidities and Mortality
Late preterm and early term infants are physiologically and metabolically less mature than late term infants. Risks of respiratory distress and death and/or a severe neurologic disorder are inversely associated with gestational age (Figs. 2 and 3).3, 6, 8, 9, 23, 24 In a population-based study of 150,426 live-born infants, severe respiratory failure (ie, treatment with mechanical ventilation and/or nasal continuous positive airway pressure) decreased from 20% at 34 weeks’ gestation to 0.3% at
Management of late preterm and early term infants
The focus of care of late preterm and early term infants is individualized depending on the specific medical and social issues that may occur. Counseling of women by pediatric and obstetric caregivers about the possible outcomes for late preterm and term infants is important when delivery of such infants is indicated so that families are informed of possible morbidities, admission to neonatal intensive care, prolonged birth hospitalizations, and readmission for hospital care. If delivery of
Causes of late preterm and early term births
Preterm births have increased for many reasons including demographic changes of women who become pregnant (such as delayed childbearing), infertility treatments, increased maternal age, increased multiple gestations, and maternal comorbid conditions including obesity.58 Several risk factors have been identified for late preterm and, by extrapolation, early term births.58, 59, 60 Late preterm birth has been associated with chorioamnionitis (relative risk, 3.1; 95% confidence interval, 2.6–3.7),
Summary
Late preterm and early term infants have significantly greater risks of medical complications and morbidities during the birth hospitalization and during the first weeks after birth than term infants. Neonatal and infant mortality and morbidity rates are largely influenced by gestational age with the lowest rates at 39 to 40 weeks’ gestation. Neonatal morbidity and mortality are significantly increased by maternal or fetal illness. Long-term morbidities occur in a small, but significant,
References (76)
- et al.
Determinants of morbidity in late preterm infants
Early Hum Dev
(2010) - et al.
Changes in the gestational age distribution among U.S. singleton births: impact on rates of late preterm birth, 1992–2002
Semin Perinatol
(2006) - et al.
Adverse neonatal outcomes: examining the risk between preterm, late preterm and term infants
Am J Obstet Gynecol
(2008) A recommendation for the definition of “late-preterm” (near-term) and the birth weight-gestational age classification system
Semin Perinatol
(2006)- et al.
The cost of prematurity: quantification by gestational age and birth weight
Obstet Gynecol
(2003) - et al.
Emergency department visits and rehospitalizations in late preterm infants
Clin Perinatol
(2006) - et al.
Early discharge among late preterm and term newborns and risk of neonatal mortality
Semin Perinatol
(2006) - et al.
School outcomes of late preterm infants: special needs and challenges for infants born at 32 to 36 weeks gestation
J Pediatr
(2008) Preeclampsia as a cause of preterm and late preterm (near-term) births
Semin Perinatol
(2006)- et al.
Indications for late preterm birth, can obstetricians make a difference?
Am J Obstet Gynecol
(2008)
Indications for delivery and short-term neonatal outcomes in late preterm as compared with term births
Am J Obstet Gynecol
Late preterm birth: how often is it avoidable?
Am J Obstet Gynecol
The influence of obstetric practices on late prematurity
Clin Perinatol
Premature rupture of membranes at 34 to 37 weeks’ gestation: aggressive versus conservative management
Am J Obstet Gynecol
Induction versus expectant management in premature rupture of the membranes with mature amniotic fluid at 32 to 36 weeks: a randomized trial
Am J Obstet Gynecol
Later preterm gestation: physiology of labor and implications for delivery
Clin Perinatol
Rethinking the definition of “term pregnancy”
Obstet Gynecol
Elective delivery at less than 39 weeks
Curr Opin Obstet Gynecol
Consortium on Safe Labor. Respiratory morbidity in late preterm births
JAMA
Mortality of late-preterm (near-term) newborns in Utah
Pediatrics
Late preterm birth and neonatal outcome: is 37 weeks’ gestation a threshold level or a road marker on the highway of perinatal risk?
Birth
Increased risk of adverse neurological development of late preterm infants
J Pediatr
Short-term neonatal outcome in low-risk, spontaneous, singleton, late preterm deliveries
Obstet Gynecol
Neonatal outcome associated with singleton birth at 34–41 weeks of gestation
Int J Epidemiol
Optimizing care and outcome for late-preterm (near-term) infants: a summary of the workship sponsored by the National Institute of Child Health and Human Development
Pediatrics
Births: preliminary data for 2008
Natl Vital Stat Rep
Births: final data for 2006
Natl Vital Stat Rep
Neonatal respiratory morbidity and mode of delivery after term: influence of timing of elective caesarean section
J Obstet Gynaecol
Neonatal respiratory morbidity risk and mode of delivery at term: influence of timing of elective caesarean delivery
Acta Paediatr
Timing of elective repeat cesarean delivery at term and neonatal outcomes
N Engl J Med
Fetal lung maturity. Practice Bulletin No. 97
Obstet Gynecol
Induction of labor. Practice Bulletin No. 107
Obstet Gynecol
Decreasing elective deliveries before 39 weeks of gestation in an integrated health care system
Obstet Gynecol
Reduction in elective delivery at <39 weeks of gestation: comparative effectiveness of 3 approaches to change and the impact on neonatal intensive care admission and stillbirth
Am J Obstet Gynecol
A statewide initiative to reduce inappropriate scheduled births at 36(0/7)-3(6/7) weeks’ gestation
Am J Obstet Gynecol
Late-preterm birth. Does the changing obstetric paradigm alter the epidemiology of respiratory complications?
Obstet Gynecol
Resuscitative procedures at birth in late preterm infants
J Perinatol
Cited by (121)
Risks of stillbirth, neonatal mortality, and severe neonatal morbidity by birthweight centiles associated with expectant management at term
2023, American Journal of Obstetrics and GynecologyThe effect of tocolytics in women with preterm labor after 34 weeks of gestation: A propensity score-matched study
2022, European Journal of Obstetrics and Gynecology and Reproductive BiologyThe cause of birth is associated with neonatal prognosis in late preterm singletons
2020, Journal of Gynecology Obstetrics and Human Reproduction
Disclosures: The author has nothing to disclose.