Study Pinpoints 4 Factors That Influence Survival Odds for Babies Born at 22-

Study Pinpoints 4 Factors That Influence Survival Odds for Babies Born at 22-25 Weeks

By Miranda Hitti

WebMD Medical NewsReviewed by Louise Chang, MDApril 16, 2008 -- For babies born extremely early, new research shows that four factors -- aside from the baby's gestational age -- may affect their odds of survival if given intensive care.

The four factors are:

Sex (survival is better for girls)

Single birth or multiple birth (survival is better for singletons)

Mother's treatment with corticosteroids before giving birth to help the baby's lungs develop (a plus for preemie survival)

Birth weight (the higher the better)

So says a new study of more than 4,000 extremely preterm babies born in the U.S. at 22-25 weeks of gestation.

The study is \"exciting,\" says Donna R. Halloran, MD, MSPH, assistant professor of pediatrics at St. Louis University, who reviewed the study for WebMD.

\"I think without a doubt it will change the way we counsel families,\" says Halloran, who plans to start using the findings right away in counseling parents of extremely preterm babies.

U.S. preterm births are up 21% since 1990, according to a recent report in Pediatrics. Most of those preemies are born at 34-36 weeks of gestation, not at the much younger ages covered in the new study, which appears in The New England Journal of Medicine.

Extremely Preterm Babies

The researchers -- who included Jon Tyson, MD, MPH, of the University of Texas Medical School at Houston -- tracked the babies from birth up to 22 months.

At birth, 83% of the babies got intensive care with mechanical ventilators to help them breathe. That decision was up to the parents and their doctors, not the researchers, who simply tracked the babies' progress.

Of the nearly 4,200 babies with follow-up information available 18-22 months after birth, 61% had died or had profound impairment.

Among babies who got intensive care, survival rates were better for girls, singletons, babies whose mothers had gotten corticosteroid treatment before giving birth, and babies with higher birth weights.

Considering those factors, along with gestational age, may help parents and doctors gauge the chance that intensive care will lead to a \"favorable outcome,\" Tyson's team writes.

Still, those patterns are \"no substitute for sound medical judgment\" tailored to each baby, Rosemary Higgins, MD, of the National Institute of Child Health and Human Development, tells WebMD.

Higgins, who worked with Tyson and other scientists on the study, says it's not clear why survival rates were better for girls than boys. \"There's probably some biologic difference that we don't understand yet,\" Higgins says.

Better Counseling for Parents
What the study really gets at, Halloran says, is what sort of interventions parents want for their extremely preterm child.

She reels off a list of questions those parents face, sometimes with only hours to decide before a baby is born way before its due date.

\"Should we be intervening? Should we be performing resuscitation on the baby? Should we be putting them on a ventilator? Should we be taking what are sometimes very extreme measures to save this baby? What's going to happen to the baby after that?\" asks Halloran, who didn't work on Tyson's study.

\"It's such a difficult time\" for parents, she says. \"What they want more than anything is information.\"

\"Of course, they want to know what's going to happen to their child. But I can't tell them that. ... We can't predict the future but we can give them probabilities. ... Now we can be much more specific and much more knowledgeable and confident in the counseling that we're providing.\"

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