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Pediatric Bioethics

May, 2018

What Do We Know about Outcomes for Babies Born at the Borderline of Viability?


John D. Lantos, MD | Director of Pediatric Bioethics | Professor of Pediatrics

Most people have pretty strong opinions about whether or not treatment should be offered to babies born at 22 or 23 weeks of gestation. Many centers do not offer lifesaving treatment at these gestational ages. Others recommend it. But most of what we think we know about outcomes for these babies is probably systematically wrong. That is because most reported outcome statistics have well-known, easily identifiable, and theoretically correctable errors.

Here are some of the most common errors

  1. Outcome statistics are reported for all live births regardless of whether they were given any active interventions aimed at keeping them alive. For example, Rysavy et al., reported that for babies born at 22 weeks in the U.S., overall survival was 5 percent, but survival among babies who received active treatment was 25 percent.1  Many people, including professional societies, cite that paper in support of their claim that survival is <5 percent regardless of whether or not attempts were made to resuscitate and save babies.2   We simply don't know what the survival rate would be if resuscitation were offered or provided to all babies.3

  2. Different centers and different countries use imprecise or idiosyncratic definitions of stillbirth. “Stillbirth” may refer to late fetal death, which is a death after 28 weeks of gestation, or at least 1,000 grams birth weight, or it may include early fetal death, which is a death after 22 weeks of gestation or at least 500 grams birth weight. In some countries, any baby born at less than 24 weeks or 500 grams is classified as a stillbirth, even if they were born with signs of life. This would decrease the number of “live births” and might lead to an overestimate of actual survival rates.4

  3. Finally, different centers take different approaches to active obstetrical management at low gestational ages. Some antenatal interventions, like antenatal steroids, lead to better outcomes. If reported outcomes do not distinguish babies whose mothers received steroids from those whose mothers didn’t, it could lead to worse reported outcomes than would be achieved if steroids were routinely administered. But, we don’t know the magnitude of the likely change. 

These inaccuracies and misrepresentations have real-world effects. They lead to clinical decisions, institutional policies and national policies about which babies are viable and which are not. Babies who are deemed non-viable are, of course, not treated, and the prediction of non-viability becomes a self-fulfilling prophecy. Alternatively, some centers, or some countries, change their policies, treat “non-viable” babies, and report better outcomes than are reported in many studies. At some such centers, survival rates for babies born at 22 weeks are above 30 percent. Survival rates for babies born at 23 weeks are above 50 percent. 

There are two important responses to these errors – one methodological and one for doctors who counsel parents today. Methodologically, we should change and standardize the ways that we collect and report perinatal outcomes. The denominator should be every fetus that is alive at 20 weeks. Outcomes would then include 1) termination of pregnancy; 2) intra-uterine fetal demise; 3) stillbirth (with reports of whether or not a heartbeat was present at birth); 4) survival; and 5) neurodevelopmental impairment. Such an approach has been recommended by several prominent perinatal epidemiologists.5,6  Such data, if standardized and reported, would avoid the sorts of biases noted previously. It would allow us to avoid misinforming parents and allow clinical decisions for premature babies that are based on solid facts. 

As clinicians, we should recognize the limitations of current data when counseling parents. We should use reported data with caution and understand that the clinical circumstances of each case are unique. Often, the best way to prognosticate for any individual baby is through a trial of therapy, careful observation of the response to therapy, and ongoing communication with parents about the ways that response to therapy might change our prior estimates of prognosis.7

References:

  1. Between-hospital Variation in Treatment and Outcomes in Extremely Preterm Infants. Rysavy MA, Lei L, Bell EF. N Engl J Med 2015;372:1801-11.

  2. American College of Obstetricians and Gynecologists; Society for Maternal-Fetal Medicine ACOG Obstetric Care Consensus No. 3. Summary: Periviable Birth. Obstet Gynecol. 2015;126:1123-5.

  3. Variation of Practice and Poor Outcomes for Extremely Low Gestation Births: Ordained before Birth? Janvier A, Baardsnes J, Hebert M, Newell S, Marlow N. Arch Dis Child Fetal Neonatal Ed. 2017;102(6):F470-F471.

  4. Methodological Challenges in International Comparisons of Perinatal Mortality. Joseph KS, Razaz N, Muraca GM, Lisonkova S. Curr Epidemiol Rep 2017;4:73-82. 

  5. Survival of Infants Born at Periviable Gestational Ages. Patel RM, Rysavy MA, Bell EF, Tyson JE. Clin Perinatal. 2017;44:287-303.

  6. The Fetus-at-risk Approach: Survival Analysis from a Fetal Perspective. Joseph KS, Kramer MS. Acta Obstet Gynecol Scand 2018; 97:454-55. 

  7. The Value of a Trial of Therapy - Football as a 'Proof-of-concept.’ Meadow W, Meadow X, Tanz RR, Lagatta J, Lantos J. Acta Paediatr. 2011;100(2):167-9.