ReviewThe epidemiology, etiology, and costs of preterm birth
Introduction
Preterm birth (PTB), defined as delivery prior to 37 weeks of gestation, is considered one of the leading health indicators of a nation [1], as it is the most frequent cause of neonatal death and the second most frequent cause of death in children aged <5 years worldwide [2]. Furthermore, those infants who do survive have higher rates of long-term morbidity, including neurologic and developmental disabilities, compared to infants born full term [3]. The development of effective preventive measures to reduce the incidence of PTB is, thus, urgently needed. This requires a thorough understanding of the epidemiology of the condition as well as familiarity with the previously studied factors thought to be related to pathogenesis. But perhaps most importantly, progressive approaches to studying this longstanding public health problem are essential.
Section snippets
Recent trends in preterm birth rates
During the latter part of the 20th century, an alarming increase in the PTB rate occurred in the USA as well as in other countries worldwide [4], [5]. Multiple factors were thought to have contributed to the rising PTB rate including higher average maternal age, more frequent use of assisted reproductive technologies, an increase in non-infertility-related multiple gestations (multiple gestation will be discussed elsewhere in this volume), and higher rates of preterm inductions and cesarean
Racial disparities in preterm birth
One of the most persistent findings in the study of the epidemiology of PTB is that rates of PTB vary according to women's racial and ethnic background. This disparity is most clearly evident in the relatively heterogeneous US population. In 2013, 16.3% of pregnant non-Hispanic black women delivered prior to 37 weeks compared to only 10.2% of non-Hispanic white women and 11.3% of Hispanic women. Additionally, the early PTB rate (<32 weeks) in non-Hispanic black women was more than twice the
Approaches to the study of the etiology of premature birth
Preterm birth is often regarded as a single outcome in clinical practice, public policy, and research. However, in reality, numerous biological mechanisms that vary between individuals are thought to lead to PTB. These etiologic pathways are poorly understood, despite significant research efforts. In contrast, there are multiple well-established risk factors for PTB, many of which are addressed in other chapters of this issue of Seminars (Box 1). The identification of risk factors by clinicians
The cost of prematurity
In 2005, it was estimated by the Institute of Medicine (IOM) that the societal cost of PTB in the USA annually was $26 billion [33]. This value included medical care costs up to age 5 years for children born preterm, maternal delivery costs, and the cost of early intervention. In addition, disability-specific lifetime medical, special education, and lost productivity costs for four specific developmental disabilities that are associated with PTB, including cerebral palsy, mental retardation,
Conclusion
Whereas the PTB rate is declining in many developed countries, currently about one in every eight infants in the USA is born prematurely. The consequences of PTB are substantial as it is associated with higher rates of infant morbidity and mortality, increased risk of long-term medical complications and neurodevelopmental impairment, family stress, and significant societal cost. The prevention of PTBs is a public health priority. However, research in the area of PTB prevention, although
Conflict of interest statement
None declared.
Funding sources
None.
References (63)
- et al.
National, regional, and worldwide estimates of preterm birth rates in the year 2010 with time trends since 1990 for selected countries: a systematic analysis and implications
Lancet
(2012) - et al.
Preventing preterm births: analysis of trends and potential reductions with interventions in 39 countries with very high human development index
Lancet
(2013) - et al.
Validation of birth certificate data. A study of women in New Jersey’s HealthStart program
Ann Epidemiol
(2001) - et al.
Comparison of pregnancy dating by last menstrual period, ultrasound scanning, and their combination
Am J Obstet Gynecol
(2002) - et al.
First- and second-trimester ultrasound assessment of gestational age
Am J Obstet Gyencol
(2004) - et al.
Modeling community-level effects on preterm birth
Ann Epidemiol
(2003) - et al.
Neighborhood socioeconomic status, maternal race and preterm delivery: a case–control study
Ann Epidemiol
(2002) - et al.
Racial and ethnic disparities in preterm birth: the role of stressful life events
Am J Obstet Gynecol
(2004) - et al.
The risk of preterm birth across generations
Obstet Gynecol
(1997) - et al.
Epidemiology and causes of preterm birth
Lancet
(2008)
Challenges in defining and classifying the preterm birth syndrome
Am J Obstet Gynecol
Impairment of growth in fetuses destined to deliver preterm
Am J Obstet Gynecol
Fetal growth and onset of delivery: a nationwide population-based study of preterm infants
Am J Obstet Gynecol
The preterm birth syndrome: issues to consider in creating a classification system
Am J Obstet Gynecol
The preterm birth syndrome: a prototype phenotypic classification
Am J Obstet Gynecol
Economic costs associated with moderate and late preterm birth: primary and secondary evidence
Semin Fetal Neonatal Med
Leading health indicators for healthy people 2020: letter report
Neurologic and developmental disability at six years of age after extremely preterm birth
N Eng J Med
Births: final data for 2013
Global report on preterm birth and stillbirth (1 of 7): definitions, description of the burden and opportunities to improve data
BMC Pregn Childbirth
Trends in spontaneous and indicated preterm delivery among singleton gestations in the United States, 2005–2012
Obstet Gynecol
International comparisons of infant mortality and related factors: United States and Europe, 2010
Preterm birth time trends in Europe: a study of 19 countries
Br J Obstet Gynaecol
Neonatal outcomes of extremely preterm infants from the NICHD Neonatal Research Network
Pediatrics
Infant mortality statistics from the 2013 period linked birth/infant death data set
Neonatal mortality and morbidity rates in late preterm births compared with births at term
Obstet Gynecol
Optimizing care and outcome for late-preterm (near-term) infants: a summary of the workshop sponsored by the National Institute of Child Health and Human Development
Pediatrics
Timing of indicated late-preterm and early-term birth
Obstet Gynecol
ACOG committee opinion no. 561: nonmedically indicated early-term deliveries
Obstet Gynecol
Trends in preterm birth and perinatal mortality among singletons: United States, 1989 through 2000
Obstet Gynecol
Assessing the quality of medical and health data from the 2003 birth certificate revision: results from two states
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