Clinical Review

A summary of the new ACOG report on neonatal brachial plexus palsy. Part 1: Can it be predicted?

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This expert dissects the brand new 100-page report examining this phenomenon, from risk factors to its association (and lack of it) with shoulder dystocia


 

References

Neonatal brachial plexus palsy (NBPP) after a delivery involving shoulder dystocia is not only a clinical disaster—it constitutes the second largest category of litigation in obstetrics.1

Lawsuits that center on NBPP often feature plaintiff expert witnesses who claim that the only way a permanent brachial plexus injury can occur is by a clinician applying “excessive” traction on the fetal head during delivery. The same experts often claim that the mother had multiple risk factors for shoulder dystocia and should never have been allowed a trial of labor in the first place.

The jury is left suspecting that the NBPP was a disaster waiting to happen, with warning signs that were ignored by the clinician. Jurors also may be convinced that, when the dystocia occurred, the defendant handled it badly, causing a severe, lifelong injury to the beautiful child whose images they are shown in the courtroom.

But this scenario is far from accurate.

ACOG publishes new guidance on NBPPThe American College of Obstetricians and Gynecologists (ACOG) periodically issues practice bulletins on the subject of shoulder dystocia, the most recent one written in 2002 and reaffirmed in 2013.2 These bulletins are, of necessity, relatively brief summaries of current thinking about the causes, pathophysiology, treatment, and preventability of shoulder dystocia and associated brachial plexus injuries.

In 2011, James Breeden, MD, then president-elect of ACOG, called for formation of a task force on NBPP. The task force’s report, Neonatal Brachial Plexus Palsy,3 was published earlier this year and represents ACOG’s official position on the important—but still controversial—subjects of shoulder dystocia and NBPP. This report should serve not only to help clinicians better understand and manage these entities but also as a foundational document in the prolific and complex medicolegal suits involving them.

Given the length of this report, however, a concise summary of the key takeaways is in order.

NBPP and shoulder dystocia are not always linked

Early in the report, ACOG presents three very important statements, all of which challenge claims that are frequently made by plaintiffs in brachial plexus injury cases:

  1. NBPP can occur without concomitant, clinically recognizable shoulder dystocia, although it often is associated with shoulder dystocia.
  2. In the presence of shoulder dystocia, all ancillary maneuvers necessarily increase strain on the brachial plexus, no matter how expertly the maneuvers are performed.
  3. Recent multidisciplinary research now indicates that the existence of NBPP after birth does not prove that exogenous forces are the sole cause of this injury.

These findings raise a number of questions, including:

  • Can NBPP be predicted and prevented?
  • What is the pathophysiologic mechanism for NBPP with and without shoulder dystocia?
  • Are there specific interventions that may reduce the frequency of NBPP?

In Part 1 of this article, I summarize ACOG data on whether and how NBPP might be predicted. Part 2, to follow in October 2014, will discuss the pathophysiologic mechanism for NBPP and discuss potential interventions.

The data on NBPP without shoulder dystocia
The results of 12 reports published between 1990 and 2011 describe NBPP (temporary and persistent) that occurred without concomitant shoulder dystocia. These reports indicate that 46% of NBPP cases occurred without documented shoulder dystocia (0.9 ­cases/1,000 births).

Persistent NBPP. Two of these reports provide data on persistent NBPP without shoulder dystocia. Even when injury to the brachial plexus was documented as lasting more than 1 year, 26% of cases occurred in the absence of documented shoulder dystocia.

NBPP sometimes can occur during ­cesarean delivery. Four studies evaluated more than 240,000 births and found a rate of NBPP with cesarean delivery ranging from 0.3 to 1.5 cases per 1,000 live births.

All of these studies are described in the ACOG report.

When NBPP is related to shoulder dystocia
Shoulder dystocia may occur when there is a lack of fit of the transverse diameter of the fetal shoulders through the different pelvic diameters the shoulders encounter as they descend through the pelvis during the course of labor and delivery. This lack of fit can be related to excessive size of the fetal shoulders, inadequacy of pelvic dimensions to allow passage of a given fetus, or both. Abnormalities of fetal anatomy, fetal presentation, and soft tissue obstruction are rarely the cause of shoulder dystocia.

The difference between anterior shoulder obstruction behind the symphysis pubis and posterior shoulder obstruction from arrest at the level of the sacral promontory also is discussed in the ACOG report. In both cases, it is this obstruction of the affected shoulder while the long axis of the body continues to be pushed downward that widens the angle between the neck and impacted shoulder and stretches the brachial plexus.

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