Among the respondents, 57 (22%) were board certified in maternal–fetal medicine and their response was compared with 201 ob-gyns. Among the 22 clinical questions, the response for the two groups was significantly different for 32% (seven) of them (Table 3). As noted in Table 3, there were significant differences between ob-gyns and maternal–fetal medicine specialists. These areas included offering elective cesarean delivery for estimated fetal weight of at least 4,500 g among nondiabetics, the occurrence of brachial plexus palsy without concomitant shoulder dystocia, and the cause of shoulder dystocia-related brachial plexus palsy.
A relatively large percentage of respondents felt that a specific timeframe could be used for the diagnosis of shoulder dystocia. Despite the presence of an objective definition, the American College of Obstetricians and Gynecologists (the College) does not acknowledge this in its definition.1,5,6 In Hoffman's recent multicenter study describing 2,018 cases of shoulder dystocia, there were only two instances in which the delivery note documented a head-to-body delivery time greater than 60 seconds.7
In our study, we found that just 58% of general ob-gyns would use the College Bulletin-estimated fetal weight thresholds for their clinical decision-making. A similar finding has been reported in a publication emanating from a nonteaching hospital, in which clinicians disregarded the College thresholds for suspected fetal macrosomia.8 We hypothesize that this may be because the College recommendations are based primarily on consensus and expert opinion.9 Finally, we cannot exclude the possibility that generalists are not willing to face the potential medicolegal risk attendant with accelerated birth weights.
Recurrence risks for shoulder dystocia have been quoted to range from approximately 10% to 25%.10 We found that nearly 40% of Central Association of Obstetricians and Gynecologists members would allow a trial of labor in a patient with a documented history of a prior vaginal delivery complicated by shoulder dystocia. Possible explanations for this lack of consensus include the lack of randomized trials and insufficient data among patients with prior shoulder dystocia. Health care providers may also desire clearer recommendations from the College, because the bulletin simply notes that “after discussion with the patient, either method of delivery is appropriate.”1
When queried, it appears that the majority of Central Association of Obstetricians and Gynecologists members did state that they document the types and sequence of maneuvers, which arm was anterior, and the duration of the dystocia. We are, however, unable to conclude whether this practice of documentation actually translates to their clinical practice. Several authors have commented that these items are key components of shoulder dystocia checklists and can be helpful should litigation ensure.11–13
The belief that all brachial plexus injuries result from inappropriate maneuvers at delivery has no scientific foundation.1,2,14 In the past 10–15 years, epidemiologic data, case studies, and computer modeling have all provided support to the theory that brachial plexus stretch and injury can result from maternal forces when the neonate's shoulder presses against the bony pelvis of the mother.15 We were therefore surprised by the fact that nearly one-third of respondents felt that the most likely cause of brachial plexus injury with shoulder dystocia resulted from traction applied by the clinician doing the delivery. We also found that almost all of the Central Association of Obstetricians and Gynecologists respondents did not report using either lateral or “excessive” traction in their management of shoulder dystocia. In our study design, however, we did not specifically designate what constituted either “excessive” or lateral traction. We envision that Central Association of Obstetricians and Gynecologists members could have had varying definitions of “excessive” traction such as a level of force unreasonable or unwarranted under the circumstances. There is, however, no current clinical study that has determined an injury-producing level that would equate with either excessive or laterally derived traction.
Limitations of the study should be acknowledged. We recognize that the artificiality of the survey format places a strain on its validity. In addition, surveys are limited by response errors, response bias, and satisficing. Our findings are based on the assumption that respondents provide optimal answers, carefully interpret the meaning of each question, search their memories extensively for all relevant information, and then integrate that information carefully into summary judgments.16 Future surveys should circumvent these shortcomings and assess the validity and reliability of the survey. We acknowledge that the sample size is not formally justified and that the maximum margin of error is 6.0, which is moderately large. A survey of all College members could possibly circumvent the problem of the small sample size. Lastly, like with other surveys, there is a possibility of nonresponse bias.
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