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Postterm infant

Author
Steven Ringer, MD, PhD
Section Editor
Leonard E Weisman, MD
Deputy Editor
Melanie S Kim, MD

INTRODUCTION

Postterm infants are born at a gestational age (GA) greater than 42 weeks or 294 days from the first day of the last menstrual period. Postterm infants have higher rates of morbidity and mortality than term infants.

The epidemiology, clinical manifestations, neonatal management, and outcome of postterm infants will be reviewed here.

INCIDENCE

The incidence of postterm births varies with different patient populations and is dependent on a number of factors, such as the percentage of primigravid women, and local practice patterns regarding the rates of scheduled cesarean delivery and routine labor induction. In the United States, postterm births have decreased from 11 percent of all births in 1990 to 5.5 percent of births in 2009 [1]. In a population-based Norwegian study, the reported incidence of postterm deliveries was 7.6 percent from 1989 to 1999 [2].

In the United States, the decline in postterm births is the result of the widespread practice of inducing labor once pregnancies reach 41 weeks, a specific effort to avoid the delivery of postterm infants. (See "Postterm pregnancy", section on 'Management'.)

RISK FACTORS

The etiology of most postterm pregnancies is unknown. Risk factors for postterm births are discussed separately and include the following (see "Postterm pregnancy", section on 'Etiology and risk factors'):

          

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Literature review current through: Nov 2016. | This topic last updated: Tue Sep 20 00:00:00 GMT+00:00 2016.
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