Prematurity; Low Birth Weight; Survival: Disability--An Overview, 1/2001 

The chances that a premature baby will survive depends on the cause for the premature labor and the degree of development of the infant; the latter is ascertained by its gestational age (age in uterus) and/or birth weight. Since gestational age can sometimes be uncertain, birth weight is often used as an index of development.¹ 

The National Center for Health Statistics, a government agency, has reported that the 1st month mortality rate (rate of death per 1,000 live births) in 1997 was:

A normal pregnancy lasts about 40 weeks (gestational age) and the usual weight for a full term infant is about 7+ lbs. Babies are considered premature if they are born before 37 weeks or are less than 5 lbs. in weight. 24-26 weeks of age is considered the gray zone for survival; death generally occurs before hospital discharge if the baby is less than 24 weeks gestational age. 

The rate of prematurity has increased steadily in the past 15 years due to factors such as multiple births, often a result of fertility enhancement; multiple births is an important risk factor for prematurity. One in nine babies, about 436,000 a year, are born prematurely. 

The brain, heart and lungs are particularly prone to delayed development or injury in prematures. A study published in the New England Journal of Medicine in August 2000 found that severe disability is common among children born extremely premature. It said that more than half of children born at 25 weeks or less (40 weeks being normal) had severely delayed development when evaluated at 30 months of age; about 10% had severe neuromotor disability (C.P.) and 7% were blind. 

Comment:
Gestational age and birth weight of the infant are among the most important indices of determining the survival of an infant and the probability of survival. With the steadily increasing number of premature and low-birth weight infants being born in this country--and surviving because of the skills of the neonatal team, the occurrence of new cases of cerebral palsy is steadily increasing. Thus, prevention of prematurity has become one of the major research objectives of our Foundation. We are focusing on why does prematurity occur: what are the characteristics (biological, medical, social, etc.) of mothers at high risk of premature delivery? How can premature delivery be prevented? How to protect the premature infants brain from damage? Networking with the National Institute of Health, the Centers for Disease Control and Prevention and with the medical research community, our Foundation is giving priority attention to these questions. 

As an aside, it must be remembered that 60% of children who have cerebral palsy were NOT premature. Some of the factors that lead to their brain injury are similar to those that are involved in brain injury in the premature infant; others are not. We are also working to sort these out.
 

¹ Information derived from a number of sources including the NEJM, the National Center for Health Statistics, USA Today and previous Research Fact Sheets.
 

UCP Research & Educational Foundation, January 2001

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