Are Late-Preterm Infants Mature Enough?

December 1, 2007

In addition to term infants (born after at least 37 weeks' gestation), many hospitals currently consider late-preterm infants (born between 34 and 36 weeks' gestation) mature enough to be admitted to the well-baby nursery. Several studies, including one recently published by Young and colleagues1 from Utah, have shown an increased mortality among these late-preterm (also known as near-term) infants.

Is the well-baby nursery the best place to care for near-term infants?

In addition to term infants (born after at least 37 weeks' gestation), many hospitals currently consider late-preterm infants (born between 34 and 36 weeks' gestation) mature enough to be admitted to the well-baby nursery. Several studies, including one recently published by Young and colleagues1 from Utah, have shown an increased mortality among these late-preterm (also known as near-term) infants.

While previous studies have raised the question of where in the hospital these infants should be admitted after birth, some have had small sample sizes and others have relied on older data.

Another recently published study by Tomashek and colleagues2 may spark renewed interest in whether to care for late-preterm infants in the well-baby nursery or a special care unit. These authors used data from the National Center for Health Statistics to examine birth and death rates of singleton term and late-preterm infants--and to look at the causes of death in these infants. From 1995 to 2002, there were more than 30 million singleton live births in the United States; gestational age was reported in the database for 99% of these infants. Among those infants whose gestational age was reported, 82.1% were born at term and 7.1% were born during the late-preterm period. The authors divided the infant deaths into those that occurred at 0 to 6 days of life (early-neonatal), at 7 to 27 days (late-neonatal), and at 28 to 364 days (post-neonatal).

Overall mortality rates were at least 3 times higher among late-preterm infants than in term infants in each of the 8 years included in the study. The rate of death during the first week of life was increased 5-fold among late-preterm infants. Also, there was a 3-fold increase in the rate of death from 1 week to 1 month of life among these infants.

Using data compiled from the reports of infant deaths from 2000 to 2002, the authors examined the causes of death within each age-at-death category and compared the results of term infants and late-preterm infants. While the study was limited by dependence on recorded causes of death, mortality rates from congenital anomalies; sepsis; and abnormalities of the placenta, amniotic membrane, or cord were more than 4 times higher among late-preterm infants than term infants. Additional increases in death rates were seen from such disorders as pneumonia, atelectasis, and sudden infant death syndrome.

As the authors note, previous studies have demonstrated increased morbidity among late-preterm infants. Combined with the greater mortality seen in the Tomashek study and others, especially during the first week of life, the safety of admitting these infants to the well-baby nursery must be called into question. With increases in scheduled inductions and early deliveries related to maternal health issues, more and more infants are being born in the late-preterm period--making morbidity and mortality more likely.

We do not know whether late-preterm infants who diewould have done better had they had a longer gestation or been admitted to a special care unit. Until further studies are completed, however, we should consider admitting late-preterm infants to a unit where infants can be observed more closely than in the well-baby nursery. *

References:

REFERENCES:

1.

Young PC, Glasgow TS, Li X, et al. Mortality of late-preterm (near-term) newborns in Utah.

Pediatrics.

2007;119:e659-e665.

2.

Tomashek KM, Shapiro-Mendoza CK, Davidoff MJ, Petrini JR. Differences in mortality between late-preterm and term singleton infants in the United States, 1995-2002.

J Pediatr.

2007;151:450-456.