Estimation of Neonatal Outcome and Perinatal Therapy Use
Steven B. Morse, MD, MPH*§; James L. Haywood, MD*; Robert L. Goldenberg, MD‡; Janet Bronstein, PhD§; Kathleen G. Nelson, MD*; and Waldemar A. Carlo, MD*
ABSTRACT. Objectives. To learn whether US obste-tricians and pediaobste-tricians accurately estimate rates of sur-vival and freedom from handicap in preterm infants and to learn whether their knowledge and attitudes influence their choice of interventions that may enhance survival. Methods. A cross-sectional survey of obstetricians and pediatricians practicing in the United States was performed using a pretested questionnaire designed to identify their knowledge regarding survival and handi-cap-free rates of infants born at 23 to 36 weeks of gesta-tion. At each week of gestation, they were asked whether they would provide specific therapeutic interventions to either the expectant mother or infant. Survival and hand-icap-free rates were compared with published national rates. Obstetricians and pediatricians were divided into an optimists group and a pessimists group, based on their estimates of survival. The rates at which each group used therapeutic interventions were compared.
Results. Both obstetricians and pediatricians under-estimated survival rates from 24 through 35 weeks of gestation and freedom from serious handicap from 23 through 36 weeks of gestation. On the average, optimists accurately predicted neonatal survival. Obstetricians who underestimated neonatal survival would less often administer antenatal corticosteroids, perform a cesarean section for fetal distress, and transfer a mother to a ter-tiary center. Pediatricians who underestimated neonatal survival would less often use mechanical ventilation, cardiopulmonary resuscitation, inotropes, intravenous fluids, thermal support, and oxygen supplementation.
Conclusion. Physicians underestimate survival and freedom from handicap in preterm infants. Underestima-tion of outcome is associated with restricUnderestima-tion in the use of appropriate interventions. Pediatrics 2000;105:1046 –1050; prematurity, survival, knowledge, attitudes, practice.
ABBREVIATIONS. NICHD, National Institute of Child Health and Human Development; CI, confidence interval.
D
ecision-making by obstetricians and pediatri-cians regarding perinatal interventions relies heavily on their knowledge and attitudes. The reported misperceptions about neonatal survival and eventual quality of life for preterm infants may result in less than appropriate care for pregnantwomen and their infants.1,2Underestimation of neo-natal outcome is especially important because ad-vances in the care of preterm infants generally have improved survival without increasing rates of seri-ous handicap.3– 8 We have reported that both pedia-tricians and obstepedia-tricians in Alabama currently un-derestimate rates of survival and freedom from handicap in preterm infants.9,10Through analysis of hypothetical management by surveyed obstetricians and pediatricians in our state, it was demonstrated that physicians with inaccurate knowledge were less aggressive in attempting to salvage potentially viable fetuses and neonates.9,10This study was designed to determine if US physicians accurately estimate sur-vival and freedom from handicap of preterm infants. The study also sought to determine whether knowl-edge and attitudes about survival rates of preterm infants affect physicians’ treatment practices.
METHODS
A questionnaire that asked pediatricians and obstetricians to estimate survival and the percentage of survivors who would be expected to be free of major handicap for preterm infants born under optimal conditions at a perinatal center at 23 through 36 weeks of gestation was developed and pretested. A hypothetical case of a healthy primigravid woman in preterm labor with intact membranes was given to the obstetricians. The obstetricians were asked which interventions they would undertake at each week of gestation, including the administration of corticosteroids, admin-istration of tocolytics, monitoring of the fetus in labor, cesarean section for fetal distress, and transfer of the mother to a center capable of ventilating sick newborns (assuming their own hospital did not have that capability). The pediatricians were asked which interventions they would undertake at each gestational age in-cluding thermal support, oxygen by hood for cyanosis, intrave-nous fluids for hydration and/or nutrition, inotropic agents for treatment of hypotension, mechanical ventilation for respiratory distress, and cardiopulmonary resuscitation.
In 1993, expedited human subject approval was obtained from the University of Alabama at Birmingham Institutional Review Board. Cover letters, questionnaires, and self-addressed stamped envelopes were mailed to 1158 physicians board-certified in ob-stetrics– gynecology randomly selected from the American Col-lege of Obstetricians and Gynecologist Directory and to 699 phy-sicians randomly selected from the American Academy of Pediatrics Fellowship Directory who were not practicing a pedi-atric subspecialty. These sample sizes were chosen based on re-sponse rates in the local pretesting surveys and were randomly selected based on geographic distribution for each specialty. Ques-tionnaires were serially coded to allow for the second mailing to nonresponders. Study participants were told in the cover letter the reason for the serial number coding and assured anonymity of their responses. Two weeks after the first mailing, a second mail-ing was sent to all nonrespondents. Participants who indicated subspecialty practice or faculty status in subspecialties were elim-inated from analysis.
Multicenter data obtained from the 1988 –1989 National Insti-tute of Child Health and Human Development (NICHD) Neonatal Network11and from the 1982–1986 March of Dimes Multicenter
From the Departments of *Pediatrics, ‡Obstetrics and Gynecology, and the §Schools of Medicine and Public Health, University of Alabama at Birming-ham, BirmingBirming-ham, Alabama.
Received for publication Apr 20, 1999; accepted Sep 22, 1999.
Reprint requests to (W.A.C.) University of Alabama at Birmingham, De-partment of Pediatrics, 525 New Hillman Building, Birmingham, AL 35233. E-mail: wcarlo@peds.uab.edu
Prevention Trial12 were used for survival rates comparisons. NICHD data were chosen for gestational ages 23 through 30 weeks, inclusive, because at the time of the questionnaire, they were the most recent multicenter survival data of extremely pre-term infants published. However, because the NICHD Neonatal Network study reported outcomes of infants who were born at
⬍1500 g birth weight, only data of infants up to 30 weeks of gestation were used, because infants of⬎30 weeks of gestation were more likely to have been small for gestational age. Survival rates for infants of 31 through 36 weeks of gestation were obtained from the earlier March of Dimes Trial that entered all infants born before 37 weeks of gestation regardless of birth weight.12
Handicap-free rates from a summary of outcome studies pub-lished between 1978 and 1984 were used.13This reference was chosen because handicap rates were reported by gestational age rather than birth weight as is frequently done. Handicap-free was defined as not having a major handicap, including cerebral palsy, mental retardation (intelligence quotient: ⬍70), developmental delay (developmental quotient:⬍70), blindness, deafness, or se-vere failure to thrive. More recent reports show even lower hand-icap rates, but the data could not be used in the current study because they were analyzed by birth weight and not by gestational age.
To determine whether the estimates of survival rates correlate with the willingness to use therapeutic interventions, participants were subdivided into optimists and pessimists based on their estimates of survival rates at each gestational age. An optimist group was formed at each gestational age from those physicians who estimated survival above the median response. Similarly, a pessimist group for each week of gestation was composed of those who estimated survival below the median response. The groups were compared regarding their willingness to intervene with ther-apeutic interventions.
The estimates of survival and freedom from handicap at each gestational age were compared with rates obtained from the lit-erature review (actual) using unpairedttests performed at each gestational age between 23 and 36 weeks of gestation, inclusive. To assess the relationship between survival estimates and willing-ness to use therapeutic interventions, differences between the optimist and pessimist groups’ percent use of each intervention at each gestational age were tested for significance using2analysis. Using relative risk ratio analysis, which is commonly applied to exposure/disease dyads, optimists and pessimists were compared as to their likelihood of using each therapy. Optimists and pessi-mists were considered exposures and the use or lack of use of each therapy was considered the disease. Using this construct, 2⫻2 tables were formed and a relative risk ratio was calculated and termed likelihood of use. In keeping with relative risk ratio anal-ysis, 95% confidence interval (CIs) were also determined for each therapy at each gestational age.
RESULTS
Three hundred seventy-nine (33%) obstetricians and 362 pediatricians (52%) responded after the 2 mailings. Ninety-four percent of the obstetrician re-sponding and 75% of the pediatricians rere-sponding were able to be included after removal of those in-dicating subspecialty practice. Responding obstetri-cians were on average 45 years of age and 76% male. The percentages of obstetricians associated with each nursery level were: 47% with level III, 41% with level II, and 12% with level I centers. Pediatricians who responded were also on average 45 years of age and predominately male (65%). Obstetricians underesti-mated survival at each week from 23 through 36 weeks of gestation (eachP⬍.05; Fig 1). Pediatricians significantly underestimated survival rates at each week from 24 through 35 weeks of gestation (each
P⬍.05; Fig 1). In addition, both groups of physicians significantly underestimated handicap-free rates of infants from 23 through 36 weeks of gestation (each
P ⬍ .05; Fig 2). At the more advanced gestational ages, estimates of both pediatricians and
obstetri-cians were progressively closer to the actual rates. Optimists accurately estimated survival rates and handicap-free rates, whereas pessimists significantly underestimated both rates.
Among pediatricians, the optimist and pessimist groups differed in their stated willingness to use therapeutic interventions. The optimist group was 1.1 (95% CI: 1.01–1.17) to 1.8 times (95% CI: 1.22–2.67) more likely to use mechanical ventilation for infants between 23 and 27 weeks of gestation. Inotropic sup-port was 1.1 (95% CI: 1.04 –1.25) to 1.6 times (95% CI: 1.05–2.55) more likely to be used by optimists for infants 23 to 27 weeks of gestation (Fig 3). Thermal support and oxygen were more likely used by opti-mists at 24 weeks of gestation 1.9 (95% CI: 1.01–1.18)
Fig 1. Comparison of the estimates of pediatricians (‚) and
ob-stetricians (F) of survival rates to actual survival rates (⽧)
ob-tained from national data. The estimates of pediatricians were significantly lower than actual survival rates at each gestational age from weeks 24 to 35. The estimates of obstetricians were significantly lower than actual survival rates from 23 to 36 weeks of gestation.
Fig 2. Comparison of estimates of pediatricians (‚) and
obstetri-cians (F) of rates of freedom from handicap to actual
and 1.22 (95% CI: 1.07–1.39) times more likely, re-spectively. Cardiopulmonary resuscitation was 1.24 (95% CI: 1.02–1.3) to 1.35 (95% CI: 1.03–1.77) times more likely to be used by optimists at 24 and 25 weeks of gestation. Intravenous fluids were likely to be given 1.24 (95% CI: 1.11–1.39) to 1.50 (95% CI: 1.26 –1.77) times more often by optimists at 24 and 25 weeks of gestation (Fig 3). On average, the optimists indicated a willingness to use the following interven-tions earlier than the pessimists; mechanical ventila-tion at 24 versus 25 weeks (P⫽.004), inotropes at 24 versus 25 weeks (P⫽.0057), cardiopulmonary resus-citation at 25 versus 26 weeks (P⫽.01), and intrave-nous fluids at 23 versus 24 weeks of gestation (P ⫽
.017).
Among obstetricians, optimists and pessimists dif-fered in their willingness to perform a cesarean sec-tion for distress, administer steroids, and transfer of the mother in preterm labor. Optimists were 1.3 (95% CI: 1.1–1.6) to 2.8 (95% CI: 1.23– 6.21) times more likely to perform a cesarean section for distress in infants between 23 and 25 weeks of gestation (Fig 4). Antenatal corticosteriod use was 1.3 (95% CI: 1.1–1.6) times more likely at 24 weeks and 1.2 (95% CI: 1.0 – 1.3) times more likely at 25 weeks of gestation. Trans-fer of a mother in preterm labor to a tertiary center was 1.3 (95% CI: 1.0 –1.6) times more likely at 23 weeks of gestation (Fig 4). Optimists and pessimists did not significantly differ in their use of tocolytics or fetal monitoring during labor.
DISCUSSION
The purpose of this study was to determine whether physicians involved in the care of preterm infants have an accurate knowledge of survival and handicap rates and whether this knowledge affects their willingness to use therapeutic interventions. Overall, we found that both pediatricians and obste-tricians consistently underestimate both survival and
freedom from handicap of preterm infants. Addi-tionally, those physicians who thought infants would have a poorer outcome were less willing to use some therapeutic interventions at the earliest gestational ages.
To reach many physicians from a broad geo-graphic distribution, a questionnaire was used. This questionnaire was completed by 40% of its targeted audience. Although a higher response rate would have been preferred, this rate is comparable or better than that of similar studies using a survey for-mat.14 –16However, the accuracy of a questionnaire to assess knowledge, attitudes, and practice, is limited by several factors including the ability to reach the appropriate target audience and the ability of the individual respondent to interpret the questions and answer appropriately.17Survey-based data collection is also subject to other potential biases. Study partic-ipants may say what they believe is correct, although it may not agree with what they do in practice. A respondent’s answer to 1 question may be dependent on his or her answer to another. However, the ques-tionnaire used in this study is very similar to the 1 we have used extensively in the past and results of the current national study are similar to those of previ-ously published single state data.1,9,10
Obstetricians and pediatricians take care of a large number of mothers in preterm labor and their in-fants, respectively. For example, nearly one third of very low birth weight infants initially receive care outside of a tertiary care center.18 The obstetricians and pediatricians were surveyed regarding tions that they may have to initiate and not interven-tions before any necessary transfer to a tertiary center.
Although nonrespondents were not able to be compared with respondents with regard to demo-graphics, the results are consistent with previously
Fig 3. Likelihood of therapy use by pediatric optimists, compared with pediatric pessimists for infants between 23 and 36 weeks. Ventilation (F) and inotropic support (䡲) were more likely used
between 23 and 27 weeks (P⬍.05). Cardiopulmonary resuscita-tion (‚) and intravenous fluids (⽧) were more likely used
be-tween 24 and 25 weeks (P⬍.05). Warmth (〫) and oxygen (䡲) were more likely used between at 24 weeks (P⬍.05).
Fig 4. Likelihood of therapy use by obstetric optimists, compared with obstetric pessimists for infants between 23 and 36 weeks. Cesarean section for fetal distress (F) was used more likely
be-tween 23 and 25 weeks (P ⬍.05). Antenatal corticosteroids (‚)
were used more likely at 24 to 25 weeks by optimists (P⬍.05). Perinatal transport to a tertiary center (䡲) was more likely at 23 weeks (P⬍.05). Use of tocolysis (⽧) and monitoring (〫) did not
published data from our statewide survey in which responders and nonresponders were found to be comparable with regard to gender makeup. In the statewide survey, responders were board-certified later and tended to work in areas without neonatol-ogists. These differences would likely make nonre-spondents more likely to underestimate outcome than respondents. However, it is possible that in the current study, the nonresponders were different in some way.
Another limitation in this study design is the se-lection of the survival data. Survival data for this study were taken from 2 large multicenter databases that were the most recent sources available to re-spondents at the time of the survey.11,12 Since then, more recent outcome results have been published by the NICHD Neonatal Research Network.19These re-sults evaluate a cohort born between January 1993 and December 1994. In all birth weight categories between 501 g and 1500 g, mortality and morbidity decreased. Although the databases are primarily from academic centers and the questionnaire primar-ily targeted nonacademic physicians, recent data in-dicate that outcomes at nonacademic centers are comparable to academic centers in the very low birth weight population.20,21Most, but not all, recent stud-ies report that survival of preterm infants continues to improve.6,7,22,23If more current data with improved survival had been used for comparison, the under-estimation by the physicians surveyed would have even been more marked. In contrast, despite the increase in survival, handicap-free rates reported in recent years continue to be comparable to the refer-ence rates used in this study.24 –29
Uniform standards for the prediction and descrip-tion of long-term impairment in children are elusive. Handicap rates for surviving preterm infants are measured and reported according to variable criteria, including type of impairment (sensory, motor, and intellectual), age at follow-up, and testing protocol. Although most investigators agree on what generally constitutes severe handicap, it is possible that the physicians’ interpretations differ, accounting for part of the underestimation of handicap-free rates. No precise definition of severe handicap was given in the questionnaire because we wanted the physicians to give an overall estimate of any severely handicap-ping conditions. Pediatricians’ responses may have been influenced by their experience with preterm infants with normal early physical and neurologic examinations, who manifested difficulties later, such as on school entry.30,31
Physicians’ personal beliefs regarding outcome have been shown to influence their practice policies, counseling messages, and use of therapies.32,33 In a recent review of the ethical dilemmas of delivery room resuscitation, Stevenson and Goldworth34 cau-tion that “the likelihood of survival with or without injury . . . is influenced by the opinions and associ-ated decisive behaviors of people who prejudge the biological incapacities before they are demonstrat-ed.” Surveys of physicians’ beliefs regarding the prognosis of preterm infants have been published using various formats. Wilson et al14 found that
among obstetricians, family practitioners, and pedi-atricians, pediatricians were most accurate in their assessment of prognosis and that all physicians were more accurate in their prediction of mortality than morbidity. Among neonatologists surveyed in 1995, most counseled parents that mortality was 75% or greater at gestational ages of 24 weeks or less and up to 50% for gestational ages between 25 and 27 weeks.15 These beliefs regarding outcome coincided with a majority of the same respondents not willing to resuscitate infants⬍27 weeks of gestation.15More than 90% of obstetricians surveyed in California viewed future quality of life as dismal for infants 24 weeks or less.16 Based on this knowledge, ⬎90% of these obstetricians would call a pediatrician to the delivery of a 25-week infant and 46% would do so for a 22-week infant.16 These reports exemplify the con-nection between physicians’ beliefs and their actions regarding care, regardless of the accuracy of their beliefs.
Reduction in infant mortality continues to occur with advances in neonatal care.20,35However, many question the aggressive management of extremely immature neonates who might have significant mor-bidity if they survive.22Survival has been shown to improve with improved access to advanced perinatal services.9,36 – 40 Despite increased rates of maternal and fetal referral to a perinatal center, there are many preterm infants born in hospitals without advanced perinatal services40,41underscoring the importance of the attitudes of both obstetricians and pediatricians regarding lifesaving therapeutic practices for poten-tially viable infants. Very low birth weight infants not transferred to a center with neonatal intensive care services have significantly higher mortality rates in the first 24 hours.18
The theory of reasoned action has been applied to many health-related behaviors.42 Based on this the-ory, physicians believe that certain behaviors will lead to specific outcomes. Their knowledge of the outcome modifies their behavior and determines their attitudes. Furthermore, the views of physicians’ peers (subjective norms) when combined with their own attitudes, form the intention to perform a be-havior. This theory can provide a mechanism to identify points at which behavior can be modified. Based on the findings of this survey, it is clear that physicians’ knowledge of outcomes is associated with their willingness to institute potentially lifesav-ing therapies for the neonate. To optimize patient care, it is essential that knowledge and subjective norms be based on the most accurate information.
CONCLUSION
technolo-gies.43 In addition, physicians’ knowledge may lag behind current statistics, and this may explain the underestimation of outcome reported here. Improv-ing physicians’ knowledge regardImprov-ing outcome of preterm infants may result in more appropriate use of therapeutic interventions that may be lifesaving.
ACKNOWLEDGMENTS
This work was supported in part by Grant AL 30701007 from the Alabama Chapter, March of Dimes Birth Defects Foundation; by the Agency for Health Care Policy; and by Research Depart-ment of Health and Human Services Contract 290-92-0055 Patient Outcome Research Team on Low Birthweight.
We thank Dr John Waterbor for his review and comments regarding the statistical analysis.
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DOI: 10.1542/peds.105.5.1046
2000;105;1046
Pediatrics
Kathleen G. Nelson and Waldemar A. Carlo
Steven B. Morse, James L. Haywood, Robert L. Goldenberg, Janet Bronstein,
Estimation of Neonatal Outcome and Perinatal Therapy Use
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Estimation of Neonatal Outcome and Perinatal Therapy Use
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