New Rhythm For Preemies

BACKGROUND: Approximately 10 percent of all pregnancies in the United States result in pre-term births. A baby is considered pre-term if he is born before 37 weeks gestation. A full-term pregnancy is 37 to 40 weeks gestation. Pre-term deliveries are costly both financially and emotionally for families, and the infants are at risk for multiple health and developmental problems. A baby's chances for survival increases 3 percent to 4 percent per day between 23 and 24 weeks of gestation and about 2 percent to 3 percent per day between 24 and 26 weeks of gestation.

Most neonatal intensive care units keep babies in near darkness to simulate the mother's womb. Constant bright light has been shown to be too stressful on pre-term infants, causing irregular heart rates and decreased sleep. Now, researchers from Duke University took at hint from an adult's natural cycle of daylight and darkness, and the circadian rhythms that adults rely on for health, growth and development. During gestation babies grow within a rich circadian environment provided by the mother.

RESEARCH: In the study babies were assigned randomly to three groups: cycled light from birth, cycled light once they reached 32 weeks post conceptual age (equivalent to gestational age if the baby had not been born pre-term) and cycled light at 36 weeks post conceptual age. Infants in all three groups were similar with respect to degree of prematurity and birth weight. The babies were weighed daily. By creating an environment that may encourage growth, the Duke research suggests, these pre-term complications may be reduced.

RESULTS: The study found that exposing babies born before 31 weeks of gestation to cycled light helps them grow faster and infants who received cycled light from birth and cycled light at 32 weeks post conceptual age grew more rapidly than the babies who received cycled light just before discharge. In addition, it showed no short-term advantages to keeping infants in total near darkness -- the standard practice with many infants.

According to nurse researchers, by growing faster such pre-term infants can leave the hospital sooner and may have improved developmental outcomes. The study is published in the February 2002 issue of the Journal of Pediatrics.

A second study is underway to determine the long-term impact of the cycled light to see if the benefits continue two to five years down the road.

FOR MORE INFORMATION, PLEASE CONTACT:
Amy Austell
Medical Center News Office
387 Hanes House
Duke University Medical Center 3354
Durham, NC 27710
(919) 684-4148
E-mail: amy.austell@duke.edu

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