Gherman, Robert B. MD; Chauhan, Suneet P. MD; Lewis, David F. MD

As a result of its exceedingly infrequent occurrence, most obstetricians will only encounter shoulder dystocia a few times per year. Varied clinical management recommendations abound to prevent and deal with this condition, including prophylactic cesarean delivery and ancillary obstetric maneuvers.¹ In addition, shoulder dystocia continues to represent an obstetric emergency dictated by empiric management techniques.²

Despite an abundance of literature dealing with this condition, there still remain unresolved clinical questions concerning its management and complications. Prior clinical series reporting on shoulder dystocia have used retrospectively abstracted information from medical records.^{1 – 4} A PubMed search, using the terms “shoulder dystocia,” “practice patterns,'” “survey,” and “clinicians,” did not reveal any similar studies. This lack of good prospective data, with differing management techniques, led us to estimate current practice patterns and management plans for shoulder dystocia as well as concepts dealing with brachial plexus palsy. We undertook this survey of Central Association of Obstetricians-Gynecologists members to find out their opinions and experiences with shoulder dystocia and brachial plexus palsy.

MATERIALS AND METHODS

Approval for this study was granted from the University of Cincinnati institutional review board (Protocol Number 08122305X), because the senior author (D.F.L.) was on staff at that institution at the time that the study was designed and implemented. No identifiable participant information was collected. With permission, a current member roster was obtained from the Central Association of Obstetricians and Gynecologists.

An anonymous Internet-based 25-question survey was electronically disseminated to the 429 current members. Central Association of Obstetricians and Gynecologists members were electronically contacted using Survey Monkey (www.surveymonkey.com) using their listed e-mail addresses to ascertain if they would participate in the study. The survey was available only through acceptance of a hyperlink and all responses were kept confidential and aggregated at the completion of the study. For those individuals who did not respond, an additional opportunity to complete the assessment was provided during the 2009 annual meeting of the Central Association of Obstetricians and Gynecologists in Hawaii. Honorary or retired members as well as resident physicians were excluded from the study.

The survey included 25 questions that were collaboratively developed with input from all of the authors. The questions were developed to ascertain current practice patterns and management plans for shoulder dystocia as well as concepts dealing with brachial plexus palsy. Multiple-choice questions were developed to allow health care providers to mark all of those answers that they felt were important. Data were entered into a Microsoft Excel spreadsheet and analyzed using Instat/GraphPad software. Comparisons were made between subsets of respondents using the Mann-Whitney U test, Fisher's exact test, χ², or χ² for trend. P<.05 was considered statistically significant.

RESULTS

Of 429 Central Association of Obstetricians and Gynecologists members, 268 (62%) responded with 192 (78%) filling out the survey online. Forty-one percent (109) of the respondents had been in practice for 20 years or less. We combined the two groups of respondents because they were equally likely to be obstetrician–gynecologists (ob-gyns) compared with maternal–fetal medicine specialists (P=.915) and they had been practicing obstetrics for the same number of years (P=.065). Demographic characteristics of the respondents are listed in Table 1. The actual questions and their responses are provided in Table 2.

Table 1

Table 2

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.

Table 3

DISCUSSION

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.

REFERENCES

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