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March 1996

Postconceptional Age of Surviving Preterm Low-Birth-Weight Infants at Hospital Discharge

Author Affiliations

From the Department of Pediatrics, Madigan Army Medical Center, Tacoma, Wash.

Arch Pediatr Adolesc Med. 1996;150(3):260-262. doi:10.1001/archpedi.1996.02170280030005

Background:  Prediction of the duration of hospital stay of preterm, low-birth-weight infants currently requires inconvenient referral to published tables.

Objective:  To determine whether postconceptional age (gestational age plus chronologic age) could serve as a useful clinical marker for the more convenient prediction of individual durations of hospital stay.

Design:  Case series.

Setting:  Regional military teaching medical center with level III obstetric and neonatal services.

Patients:  Nine hundred sixty surviving preterm, low-birth-weight infants in the neonatal intensive care unit.

Main Outcome Measure:  The strength of the relationship of birth weight to postconceptional age at the time of discharge was tested by analysis of variance.

Results:  Postconceptional age at the time of hospital discharge varied in a highly predictable manner with birth weight (P<.001). The mean and variance were greatest for infants with very low birth weights and decreased with increasing birth weight. Postconceptional age at the time of discharge reached a minimum of 36.0±1.4 weeks (mean±SD) for infants with birth weights of 1750 to 2240 g.

Conclusions:  Most preterm, low-birth-weight infants meet current eligibility criteria for hospital discharge at a postconceptional age of 35 to 37 weeks. This level of maturity is sufficiently predictive to serve as a convenient, easy-to-remember clinical marker for expected durations of hospital stay. For infants with birth weights of less than 1000 g, discharge at a postconceptional age of 37 to 42 weeks is a more realistic expectation.(Arch Pediatr Adolesc Med. 1996;150:260-262)