We Know Less Than We Think We Know About Perinatal Outcomes.

Most of what we think we know about survival rates for infants born at 22 or 23 weeks’ gestational age is probably wrong. It is wrong because of some well-recognized but oddly persistent quirks in the ways that outcome data are collected and reported. Here are some of those quirks:These inaccuracies and misrepresentations have real-world effects. They lead to clinical decisions, institutional policies, and national policies in which infants are deemed either viable or nonviable. Infants who are deemed nonviable are, of course, not treated, and the prediction of nonviability becomes a self-fulfilling prophecy. Alternatively, some centers or some countries change their policies, treat nonviable infants, and report better outcomes than are reported in many studies. At some such centers, survival rates for infants born at 22 weeks are >30%.6 Survival rates for infants born at 23 weeks are >50%.The solution to these inaccuracies is easy. There should be a standard way of reporting perinatal outcomes. The denominator should be every fetus that is alive at 20 weeks. Outcomes would then include (1) termination of pregnancy, (2) intrauterine fetal demise, (3) stillbirth (with reports of whether a heartbeat was present at birth), (4) survival, and (5) neurodevelopmental impairment. Such an approach has been recommended by several prominent perinatal epidemiologists.7,8 Such data, if standardized and reported, would avoid the sorts of selection bias reported by Atwell et al4 as well as the other sorts of biases noted above. It would allow us to avoid misinforming parents and allow clinical decisions for premature infants to be based on solid facts.