Premature infant

Alternative Names

Preterm infant; Preemie; Premie

Definition of Premature infant

A premature infant is a baby born before 37 weeks gestation.

Causes, incidence, and risk factors

At birth, a baby is classified as one of the following:


A premature infant’s organs are not fully developed. The infant needs special care in a nursery until the organ systems have developed enough to sustain life without medical support. This may take weeks to months.

Signs and tests

The infant may have difficulty breathing and maintaining body temperature.


When premature labor develops and cannot be stopped, the health care team will prepare for a high-risk birth. The mother may be moved to a center that specifically cares for premature infants in, for example, a neonatal intensive care unit (NICU).

Expectations (prognosis)

Prematurity used to be a major cause of infant deaths. Improved medical and nursing techniques have increased the survival of premature infants. The longer the pregnancy, the greater the chance of survival. Of babies born at 28 weeks, at least 90% survive.


Kimberly G. Lee, MD, MSC, IBCLC, Associate Professor of Pediatrics, Division of Neonatology, Medical University of South Carolina, Charleston, SC. Review Provided by VeriMed Healthcare Network. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc. – 1/8/2010

ADAM Medical Encyclopedia

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