Premature Infants: Factors In Survival

Each year in the U.S., approximately 40,000 babies are born between 22 and 25 weeks’ gestation, far ahead of the normal 40 weeks. Some of the most agonizing decisions in medicine are when physicians and parents are forced to decide how much, if any treatment to give an extremely premature infant. Traditionally, gestational age is used to determine the type of care a "preemie" receives after birth. For instance, a baby born in the 25th week would normally receive intensive care, but a baby born in the 22nd week would be given “comfort care.” However, researchers believe there are at least four factors other than gestational age that should be considered.

In a new study, published in The New England Journal of Medicine, researchers analyzed data from 4,446 premature infants. The babies were assessed at birth and the survivors were examined again when they reached 18 to 22 months corrected age, the age they would have been if they had been born full term. Seventy-three percent of the study infants had either died or lived but had impairment. The remaining infants lived and did not develop a disability.

The researchers found that the chances of survival, as well as survival without disability, was influenced by not only a later gestational age, but sex (females have a better survival rate), birth weight, whether they were a single or multiple birth (single babies fare better), and whether or not the mother was given antenatal corticosteroids which stimulates the development of the baby’s lungs. The researchers used the criteria to develop an online calculator of sorts, which uses these factors to determine the chances of the baby’s survival as well as the likelihood of disabilities. The tool is available in-hospital and can provide important information to help doctors and parents access the best treatment options.

Dr. Eric C. Eichenwald, medical director of the newborn center in Texas Children’s Hospital in Houston, called the study “important” and said the calculator was “a way in which we can provide more accurate information to the process of counseling parents as to what the burdens of intensive care might be.” While some extremely premature infants do well, many others die, often after weeks or even months of painful invasive procedures in the intensive care unit. Survivors often suffer problems such as brain damage, vision and hearing loss, behavior problems and other disabilities.
The study researchers estimated that if all babies born at 22 to 23 weeks received intensive care, for every 100 infants treated there would be 1,749 extra hospital days, at a typical cost of $3,400 a day, with only zero to nine additional survivors, zero to three surviving with no impairment.

Dr. Rosemary Higgins, an author of the study and a program scientist at the neonatal Research Network of the National Institute of Child Health and Human Development (NICHD) said the study and the calculator were part of an effort to give doctors and parents more solid evidence on which to base their decisions. She said people are often misled by the reports of so-called “miracle babies” who beat the odds, and wrongly envision high rates of survival and good health.

Dr. Higgins said she has no idea what effect this information will have on medical practice or whether it would change the way extremely premature infants are treated. Every case is different, and two families in the exact same situation are likely to make opposite decisions about whether or not to pursue treatment.