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Clinical Reviews


Cutting the medicolegal risk of shoulder dystocia

What’s the best way to reduce legal risks? A physician expert and clinical riskmanagement team developed practice recommendations based on actual cases.

September 2004 · Vol. 16, No. 9

Clip-and-save shoulder dystocia documentation form
Practice recommendations

Among the intrapartum events that constitute bona fide emergencies, shoulder dystocia stands out. This obstetric emergency is the focus of an increasing number of medical liability cases. Most lawsuits involving shoulder dystocia allege negligence as the cause of the brachial plexus injury, fractured clavicle or humerus, or other injury. The defendant physicians named in these suits are often accused of inappropriately managing the prenatal or intrapartum course or the dystocia itself—or of inadequately documenting the steps taken to resolve the emergency.

To glean insights into the litigation process as it involves shoulder dystocia, we retrospectively reviewed all cases closed by the Boston-based ProMutual Group, a major liability insurance carrier, over a 7-year period. We wanted to learn more about the plaintiffs themselves, as well as the clinical and medicolegal factors that led to jury awards or indemnity payments. We also wanted data that could serve as the foundation for guidelines on how to proceed in the event of shoulder dystocia, as well as a documentation tool.

CASE 1 Discrepancies, delayed assistance

This shoulder dystocia case from an insurer’s closed claim file illustrates a problem often linked to litigation. Minor changes were made to conceal the identities of the involved parties.

Nurse and physician document different times

A 31-year-old woman in her 10th week of pregnancy had one prior uncomplicated vaginal delivery of a 9 lb 7 oz infant. Her prenatal course proceeds unremarkably, with a normal glucose tolerance test and total weight gain of 36 lb. At 41 weeks and 2 days, the estimated fetal weight is documented as 4,120 g. Labor is induced with oxytocin. Because of maternal fatigue, vacuum delivery is attempted.

Notes of the physician and the nurse differ regarding the time of the first of 3 vacuum applications.

After delivery of the head, shoulder dystocia is encountered. In a note handwritten immediately after delivery, the physician states that the head was “reconstituted as right occiput anterior with the left shoulder anterior.”

In a note dictated later, however, the same physician states the right shoulder was anterior.

Help is summoned and arrives 20 minutes after the dystocia is first encountered. The time that help was summoned is in question since there is an 18-minute discrepancy between the times the physician and the nurse note that assistance was called.

Despite the use of suprapubic pressure and maneuvers including McRoberts and Wood’s corkscrew, shoulder dystocia persists for 24 minutes. Apgars of the 11 lb 3 oz infant are 0, 1, and 3. The child is resuscitated but dies within 2 days of birth.

Outcome

Settled with a 7-figure indemnity payment.

What the defense experts said

The key issues involve documentation and summoning assistance. Discrepancies in documentation almost always cast doubt upon the credibility of a defendant. Ideally, there should be no discrepancies between nurse and physician notes and, certainly, no discrepancies between 2 notes on the same case by the same physician. If, in this case, the physician realized after writing the first note that the anterior shoulder had been incorrectly identified, a correction should have been written as a separate note.

Use of the shoulder dystocia documentation tool (see) helps create a chronology of events, which may prove vital to a successful defense.

The call for help might not have been delayed if the labor and delivery unit had had a shoulder dystocia protocol including “drills” for all team members. Help should be called as soon as a shoulder dystocia is encountered so that, when needed, it is available. Under no circumstances should it take 20 minutes for assistance to arrive.

Brachial plexus injury not always caused by shoulder dystocia

Between 21% and 42% of shoulder dystocias involve an injury1—usually brachial plexus injury. Plaintiff attorneys have manipulated this fact to attribute many cases of neonatal brachial plexus injury to mismanagement of shoulder dystocia by the obstetrician.

They fault the physician for failing to estimate fetal weight, perform a timely cesarean, use appropriate maneuvers correctly, or have a pediatrician present. They criticize nothing more resoundingly than use of “inappropriate” or “excessive” lateral traction to the fetal head.2

Nontraction injuries. The reality can be strikingly different, however. Some cases of brachial plexus injury involve no traction at all.

  • Brachial plexus injuries have been reported in infants who had precipitate vaginal deliveries without any physical intervention by the obstetrician.2
  • These injuries also have occurred in infants delivered via cesarean section.1,3,4
  • In some cases, brachial plexus injuries have affected the posterior arm of neonates whose anterior arm was involved in shoulder dystocia.1,2,5-7

A retrospective study4 found that, of 39 cases of brachial plexus injury, only 17 were associated with shoulder dystocia. Similar findings have emerged from other studies.2,3,8

Other causes. It is unclear how brachial plexus injuries occur in the absence of shoulder dystocia. Some think they arise in response to infectious agents such as toxoplasmosis, coxsackievirus, mumps, pertussis, or mycoplasma pneumonia.2 Some assume a mechanical cause, such as fetal response to longstanding abnormal intrauterine pressure exerted by maternal conditions such as bicornate uterus and uterine fibroids, especially in the lower segment.1,2

When brachial plexus injuries occur in the absence of shoulder dystocia, they likely originated before labor and delivery.4 Some experts suggest serial electromyelograms within the first 7 days of life to establish a prenatal rather than intrapartum etiology. A positive electromyelogram within 1 week of birth would suggest antepartum causation.2,9

Recognizing risk factors for shoulder dystocia best way to reduce injury

Most brachial plexus injuries or impairments are associated with shoulder dystocia,9 and shoulder dystocia is the most common way brachial plexus injuries are introduced into litigation.

Decreasing the number of brachial plexusrelated liability cases, therefore, depends on decreasing the incidence of shoulder dystocia. Unfortunately, a failsafe method continues to elude both clinicians and researchers.10-12

Retrospective studies have identified certain factors that may—but do not necessarily—increase the risk of shoulder dystocia.

Prenatal risk factors include high maternal or paternal birth weight, maternal obesity, excessive weight gain during pregnancy, advanced age, short stature, multiparity, postdates, prior shoulder dystocia, small pelvis, prior delivery of a macrosomic infant, gestational diabetes in an earlier pregnancy, abnormal blood sugars in the current pregnancy, or fetal macrosomia.13,14-16

Intrapartum risk factors include a rapid or prolonged second stage, failure or arrest of descent, presence of considerable molding, and need for a midpelvic delivery.10,15

Predictability. Prospective studies have not established the predictability of shoulder dystocia. A 2000 study17 showed that 55% of cases with 1 or more risk factors experienced shoulder dystocia. Predictability increases somewhat when both maternal diabetes and fetal macrosomia complicate pregnancy, since the rate of shoulder dystocia in women with diabetes is consistently higher than in nondiabetic gravidas. This becomes a significant issue when the infant weighs more than 4,000 g.

Indications for prophylactic cesarean in women with diabetes

In 1999, Wagner et al9 found that 70% of shoulder dystocias in women with diabetes occurred when the fetal weight exceeded 4,000 g. They concluded that cesarean delivery for infants with an estimated weight over 4,250 g would reduce the rate of shoulder dystocia by 75% and increase the cesarean delivery rate by 1%.

Others are more conservative. Gross and colleagues11 suggested that, for every additional 26 cesarean deliveries, only 1 case of shoulder dystocia would be prevented.

Macrosomia. Most obstetricians and researchers still do not advocate prophylactic cesarean delivery for macrosomia alone because, by some estimates, 98% of macrosomic infants are delivered without difficulty.18 However, they do suggest that obstetricians at least consider the possibility of cesarean delivery for a macrosomic fetus when the woman has diabetes.

In a study completed in 2000, Skolbekken19 suggested a cutoff of 4,250 g for women with diabetes. Dildy20 suggested limits of more than 4,500 g for diabetic women and more than 5,000 g for nondiabetic gravidas. However, Conway and Langer21 assert that a cutoff of 4,500 g is too liberal for women with diabetes and maintain that, at this cutoff, 40% of shoulder dystocias would not be prevented.

Ultrasound measurements. Since estimates of fetal weight have a margin of error approaching 40%,9 others have chosen different parameters for determining fetal macrosomia in women with diabetes. In a retrospective study involving 31 women with gestational diabetes, Cohen et al22 found that subtracting the fetal biparietal diameter from the abdominal diameter—with both measurements obtained via ultrasound—yields a predictability score higher than estimated fetal weight. Specifically, if the difference between the 2 measurements is 2.6 cm or more, the rate of shoulder dystocia is high enough to warrant elective cesarean (FIGURE ).

FIGURE Using ultrasound measurements to predict macrosomia


A simple way to predict fetal macrosomia in women with diabetes is to subtract the fetal biparietal diameter (9.3 cm in the scan at left) from the abdominal diameter (average of 12.44 cm in the scan at right). If the difference exceeds 2.6 cm, elective cesarean is warranted. In this case it is 3.14 cm, indicating elective cesarean is warranted.

When dystocia occurs, have a plan and stick to it

Shoulder dystocia immediately places both mother and neonate at risk for temporary or permanent injury. Thus, it is imperative that all obstetricians and other health-care providers who deliver infants have a well developed plan of action for this emergency. They should immediately ask for obstetric assistance and instruct the mother to discontinue any pushing.

Attempts at vigorous downward traction should be avoided, and no fundal pressure should be applied, as these are known to increase the potential for brachial plexus injury. Gentle downward traction is considered the standard of care.17

The obstetrician’s goal is to free the impacted shoulder as quickly as possible, since a fetus can endure only 8 to 10 minutes of asphyxia before permanent neurologic damage occurs.17 The standard of care requires the obstetrician to know and use certain maneuvers to relieve shoulder dystocia. These maneuvers are designed to facilitate vaginal delivery and reduce the risk of permanent brachial plexus injury. The McRoberts maneuver, with flexion and slight rotation of the maternal hips onto the maternal abdomen, is the standard for initial relief of shoulder dystocia.17,23

CASE 2 Appropriate action was misunderstood

This shoulder dystocia case from an insurer’s closed claim file illustrates a problem often linked to litigation. Minor changes were made to conceal the identities of the involved parties.

Prompt maneuvers, good outcome

A 28-year-old gravida weighing 214 lb has had 2 previous spontaneous deliveries of infants weighing 8 lb 5 oz and 9 lb 3 oz. Except for a weight gain of more than 60 lb, the pregnancy progressed without complications, and a 3-hour glucose tolerance test was normal. At 40 weeks, the obstetrician notes “concern” about an estimated fetal weight of 10 lb. Induction is planned, but spontaneous labor begins before oxytocin can be given. After 5 hours, the head is delivered without difficulty, but shoulder dystocia follows. The obstetrician extends the episiotomy and performs McRoberts and Wood’s corkscrew maneuvers, but the dystocia persists. Upon noting cyanosis, the obstetrician fractures the infant’s clavicle and quickly delivers a 10 lb 9 oz infant with Apgar scores of 8 and 10. Pediatricians examine the child immediately and diagnose Erb’s palsy, which subsequently resolves. X-rays confirm an undisplaced fracture of the right clavicle. Although the child recovers completely, the family sues, alleging a failure to perform cesarean delivery.

Outcome

Case closed with no payment.

What the defense experts said

Key issues are documentation and informed consent. The overriding opinion of 3 experts who reviewed the case for the defense was that cesarean delivery was not indicated and that in fracturing the clavicle, the physician acted responsibly, quickly, and within the standard of care. One defense expert said failure to document exact maneuvers used to relieve shoulder dystocia deviated from the standard of care. Another defense expert said the physician should have obtained informed consent from this at-risk patient, and explained the risks of shoulder dystocia, including neonatal injury, so that the she might have been better able to appreciate the fact that the obstetrician’s fast action may have saved her child from brain damage or death.

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