Researchers believe that gestational age should not be the only factor to determine the type of care a very premature baby receives after birth.
In a new study, published in The New England Journal of Medicine, researchers found that babies born between 22 and 25 weeks gestation were more likely to survive, and survive without disability, if:
- They were born at a later gestational age
- Their mothers were given antenatal corticosteroids shortly before giving birth (a common treatment for women at risk of delivering prematurely to lower a baby's risk for respiratory distress after birth)
- They were female
- They were born single, rather than part of a multiple birth
- They had higher birth weights
Researchers analyzed data from almost 4,500 babies born between 22 and 25 weeks gestation.
They assessed the health of the surviving babies when they reached 18 to 22 months corrected age (the age they would have been if they were born at full term). Seventy-three per cent had either died or lived but developed some impairment, while the remaining lived and did not develop a disability.
Traditionally, doctors use gestational age to determine whether a preemie receives intensive-care treatment or so-called "comfort care." Intensive care includes ventilation and other life-saving, but invasive, procedures. The less-painful comfort care ensures that a baby's basic needs are met if doctors feel that intensive care is not necessary, or won't work.
Babies born at 25 weeks will usually get the full range of treatments, while a baby born at 22 weeks will most likely receive the less-invasive care.
But the researchers note that it can be hard to determine a baby's exact gestational age, so even a week's difference can mean the baby isn't getting appropriate care.
As a follow-up to their study, the researchers developed an online tool, available in-hospital to parents and physicians, to assess what type of care may be best for a baby born at a severely low birth weight (less than 1,000 grams, or 2.2 pounds).
Doctors can use the program to compile information related to the risk factors that influence survival. This should help physicians and families with the choice between intensive or comfort care.
"Every individual is different, and no single tool can precisely predict a given baby's chances of survival or disability," Dr. Duane Alexander said in a statement. Alexander is the director of the Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD).
"However, the researchers' findings, and the tool they developed, provide important information that physicians and family members can consult to help them make the most informed treatment decisions possible."
Abstract:
Intensive Care for Extreme Prematurity -- Moving beyond Gestational Age
Jon E. Tyson, M.D., M.P.H., Nehal A. Parikh, D.O., John Langer, M.S., Charles Green, Ph.D., and Rosemary D. Higgins, M.D., for the National Institute of Child Health and Human Development Neonatal Research Network
Background: Decisions regarding whether to administer intensive care to extremely premature infants are often based on gestational age alone. However, other factors also affect the prognosis for these patients.
Methods: We prospectively studied a cohort of 4446 infants born at 22 to 25 weeks' gestation (determined on the basis of the best obstetrical estimate) in the Neonatal Research Network of the National Institute of Child Health and Human Development to relate risk factors assessable at or before birth to the likelihood of survival, survival without profound neurodevelopmental impairment, and survival without neurodevelopmental impairment at a corrected age of 18 to 22 months.
Results: Among study infants, 3702 (83%) received intensive care in the form of mechanical ventilation. Among the 4192 study infants (94%) for whom outcomes were determined at 18 to 22 months, 49% died, 61% died or had profound impairment, and 73% died or had impairment. In multivariable analyses of infants who received intensive care, exposure to antenatal corticosteroids, female sex, singleton birth, and higher birth weight (per each 100-g increment) were each associated with reductions in the risk of death and the risk of death or profound or any neurodevelopmental impairment; these reductions were similar to those associated with a 1-week increase in gestational age. At the same estimated likelihood of a favourable outcome, girls were less likely than boys to receive intensive care. The outcomes for infants who underwent ventilation were better predicted with the use of the above factors than with use of gestational age alone.
Conclusions: The likelihood of a favourable outcome with intensive care can be better estimated by consideration of four factors in addition to gestational age: sex, exposure or non-exposure to antenatal corticosteroids, whether single or multiple birth, and birth weight.
