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Late preterm infants

Authors
Wanda D Barfield, MD, MPH, FAAP
Kimberly G Lee, MD, MS, IBCLC
Section Editor
Leonard E Weisman, MD
Deputy Editor
Melanie S Kim, MD

INTRODUCTION

Late preterm infants are born at a gestational age (GA) between 34 weeks, and 36 weeks and 6 days. They have higher morbidity and mortality rates than term infants (gestational age ≥37 weeks) due to their relative physiologic and metabolic immaturity, even though they are often the size and weight of some term infants [1-4]. Late preterm has replaced near term to describe this group of infants, since near term incorrectly implies that these infants are "almost term" and only require routine neonatal care [5]. The epidemiology, outcomes, and management of late preterm infants will be reviewed here.

The views reported in this article are those of the author and do not necessarily represent the official position of the Centers for Disease Control and Prevention (CDC).

DEFINITION

It is well established that gestational age has a major impact upon clinical outcome. Thus, it is necessary to standardize medical terminology related to neonatal maturation by gestational age rather than birth weight so that gestational age-appropriate care can be administered, and data from different studies can be compared.

Preterm birth – The World Health Organization (WHO), the American Academy of Pediatrics (AAP), and the American College of Obstetricians and Gynecologists (ACOG) define preterm birth as the delivery of an infant before completion of 37 weeks gestation. This occurs on or before the 259th day after the first day of the last menstrual period (LMP) of the mother.

The National Center for Health Statistics (NCHS) of the Centers for Disease Control and Prevention (CDC) generally reports data on three categories of preterm birth: overall preterm (<37 weeks gestation), moderately preterm (between 32 and 36 weeks gestation), and very preterm births (<32 weeks gestation). By convention, only completed weeks of gestation are reported. Thus, infants born five days after completing 35 weeks are reported as 35 weeks gestation, and are not rounded up to 36 weeks gestation. If a more precise gestational age is desired, a superscript to specify the number of days after the completed week of gestation is usually used.

                       

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Literature review current through: Nov 2016. | This topic last updated: Fri Aug 19 00:00:00 GMT 2016.
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