Kristie McNealy, MD

A study published this week in the New England Journal of Medicine, looked at preemies born at gestational ages between 22 weeks 0 days and 25 weeks 6 days, and tried to find factors which would favor survival and impairment free survival. The study included 4446 infants, 83% of whom (3702) received intensive care in the form of mechanical ventilation (i.e. they were placed on a ventilator). At the time of follow-up at 18-22 months, 49% of the study infants had died.

Of the babies studied, 73% had either died or were neurodevelopmentally “impaired” at 18-22 mos. In addition, 61% of the babies had either died or had profound impairment. In case you’re wondering, impairment was defined as a score of 70 or below on either the Psychomotor Developmental Index or the Mental Developmental Index of the Bayley Scales of Infant Development (on a scale of 50 to 150, with 150 indicating the most advanced development), moderate or severe cerebral palsy, bilateral blindness, or bilateral hearing loss requiring amplification. Those are not mild impairments, to say the least. To be categorized as profoundly impaired, a child had either scored below 50 on the Bayley (a child considered “untestable”), and/or they had motor impairment so severe that they required an adult’s help to move.

As far as positive predictors of survival and impairment free survival go, four important factors were identified. Not surprisingly, these factors were:

1. female gender
2. higher birth weight
3. singleton pregnancy
4. exposure to antenatal corticosteroids.

As a result of this study, a web based tool was developed to allow practitioners to quickly assess the likelihood of death or disability in extremely premature infants. Of course, the tool cannot predict what will happen to any particular infant, but it can provide statistics that doctors can share with parents in order to help them make informed decisions about resuscitation and continuation of care.

This study included a lot more interesting data and analysis than I can cover here. I encourage all of you to check it out, and leave your thoughts in our comment section.

Reference: J Tyson, N Parikh, J Langer, C Green, R Higgins. Intensive Care for Extreme Prematurity – Moving Beyond Gestational Age. NEJM. April 17, 2008. Volume 358:1672-1681.