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Editorial |
Emeritus Professor, Departments of Family Practice and Pediatrics, University of British Columbia, Vancouver; Children’s and Women’s Health Centre of British Columbia, Vancouver, BC
CORRESPONDING AUTHOR: Michael C. Klein, CCFP, FAAP, FCFP, Centre for Comminity and Child Health Research, Child and Family Research Institute, Room L408, 4500 Oak St, Vancouver, BC, V6H 3N1 Canada, mklein{at}interchange.ubc.ca
Key Words: Parturition • cesarean section • preventive care • induction of labor • term birth • epidural analgesia • birth outcomes • maternity care • practice-based research
Nicholson and colleagues have presented an intriguing and challenging study of a new approach to the management of labor near term,1 but they fail to convince that their method is actually the reason for their rather astonishing and counterintuitive results. Moreover, there is a danger that others less careful in the application of the study intervention will too enthusiastically embrace the approach—to the detriment of the women and babies whose care the investigators wish to improve.
The investigators applied preventive use of induction of labor for women at or near 38 weeks’ gestation based on a scoring tool designed principally to avoid babies that are too large and placentas that are too old to deliver adequate oxygen and nutrition to the fetus (Active Management of Risk in Pregnancy at Term, AMOR-IPAT). The physician is the unit of analysis rather than the woman or the procedure. The investigators achieved enviable results, and though their title speaks of association, it is clear that they believe that their intervention is linked causally to their results.
The problem that the new approach seeks to ameliorate is the unacceptably high cesarean section rates found in their and most other settings. Innovative methods to address this problem are much needed. The literature is replete with quality improvement programs designed to reduce cesarean delivery rates, but it is clear from the general medical literature, as well as from the obstetric literature pertinent to cesarean section,2 that only multiple concurrent approaches are successful, and the magnitude of the resultant change is small.3 Single interventions almost always fail.
NOT A SIMPLE PROBLEM, NOT A SIMPLE SOLUTION
Childbirth is a complex process that begins antepartum, even preconceptionally. Complexity theory would dictate that a simple problem can be solved with a simple solution. If childbirth were simple, a simple intervention such as preventive induction might do the job. Unfortunately, childbirth is not simple, and neither is the proposed intervention.
We can learn something about complex care for a complex problem/phenomenon from midwifery. In midwifery care in the hospital or at home, cesarean section rates and other outcomes are as good as or better than those reported in the current study.4 What is the intervention in midwifery care? It is the totality of the care. It includes a coherent philosophy and an articulated, highly noninterventive approach. Induction rates are low, and women whose pregnancy is post-term are usually allowed to progress to labor on their own much later than in conventional physician practice.
Despite their claim that the study physicians’ practice style is not different from that of the usual care group, in my view, the study physicians who practice AMOR-IPAT are using a different style. They are a dedicated group with a coherent philosophy who practice an intimate and engaged style of care that is not representative of usual care. They follow the lead of the first author and are convinced that they have a major new approach to an important problem. Although they are not midwives, they practice in many ways like midwives do. This practice style allows them to use an apparently simple intervention such as AMOR-IPAT and get good maternal results without damage to the fetus. In reality, however, their approach is not simple. It is complex and based on the totality of what they do, not only on the 2 elements of AMOR-IPAT.
An historical example of enthusiasts taking up the challenge of their leader before the intervention was fully examined is what happened when Joseph B. DeLee exhorted his followers to implement the "prophylactic forceps operation," with associated episiotomy.5 He believed this delivery style could improve outcomes for both mother and fetus at a time when, as today, there was a real problem, when childbirth was indeed quite dangerous. It seemed like a good idea at the time, and it has taken us more than 80 years to recover.
Another example of what happens when there is widespread adoption of an intervention that showed benefit, or at least no apparent problems, also comes from the induction literature. The Canadian Post-Term Trial6 and other studies of post-term pregnancy showed no increase in the cesarean section rate and good newborn outcomes when induction is undertaken early in the 41st week of pregnancy.7,8 Outside the rarified and controlled conditions of trials, however, early induction for post-term pregnancy leads to a twofold increase in cesarean section rate.9 In our Vancouver setting, post-term nulliparous women in spontaneous labor have a cesarean section rate of about 8%, whereas those induced have a cesarean section rate of 44%. Even randomized controlled trials (RCTs) cannot provide information that is externally valid for all settings.
What is the evidence that AMOR-IPAT physicians are different, not just that they used the study intervention?
Although the 5-minute APPGAR scores were comparable, the AMOR-IPAT group had statistically fewer neonatal intensive care unit (NICU) admissions. This finding is not meaningful. NICU admissions are likely an artifact subject to local practice differences. Obstetricians often or usually require a pediatrician to be in attendance at birth, and pediatricians tend to bring babies to the NICU, where they can observe, care, and bill for them. This outcome is especially true for babies delivered by cesarean section, and there were many more cesarean section deliveries in the usual care group. Family physicians usually manage the baby themselves, and they have a predisposition for keeping mother and baby together.
RULES OF CAUSALITY
Perhaps one of the best ways of assessing the likelihood that AMOR-IPAT is the actual intervention that makes the difference is to apply Hill’s criteria for causality.12
OTHER KEY POINTS
Though various statistical tests were used to minimize these differences, demographic analysis shows that women whose physicians were in the AMOR-IPAT group were younger, less often had private medical insurance, much more often had a family practice attending clinician, were more often multiparous, were taller and thinner, and less often had malposition in labor (probably because of less epidural use),16–18 all of which favor decreases in cesarean rates. Fewer late decelerations were reported on the AMOR-IPAT side, but this finding was perhaps due to less use of continuous electronic fetal monitoring by AMOR-IPAT (data not supplied).
Although there was less blood loss in the AMOR-IPAT patients, this measure is subjective and not supported by either fewer transfusions (data not supplied) or by postpartum hemoglobin levels, which were comparable for both groups. Furthermore, the use of carboprost tromethamine (Hemabate) was similar.
Of interest, in the same 2004 issue as the Nicholson et al first study,14 the editorialist compared their results with a study published concurrently in the same issue.9 That study came to the conventional conclusion that induction raises the cesarean section rate. The editorialist cautioned easy acceptance of AMOR-IPAT, counseling the reader to remember "first do no harm."19
In summary, the developers of AMOR-IPAT fail to convince that their intervention is the reason for the outcomes favoring their approach. Many confounders, demographic imbalances, and biases are at play, and the established Hill criteria for causality are far from being met. If this approach were to be taken up by physicians less committed to intimate and personalized care than the investigators and their disciples, our already industrialized maternity care patterns would be augmented by yet another reason to consider birth as an accident waiting to happen, and women would have yet another reason to consider themselves incompetent to given birth without massive intervention.
FOOTNOTES
Conflict of interest: none reported
Received for publication June 8, 2007. Accepted for publication June 13, 2008.
REFERENCES
This article has been cited by other articles:
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  K. C. Stange In This Issue: Clinical Diagnosis and Management Ann. Fam. Med, July 1, 2007; 5(4): 290 - 291. [Full Text] [PDF]
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