| The Doctor’s Advocate | Second Quarter 2008 |
Shoulder Dystocia—A Major Cause of Liability Claims in Obstetrics
by David B. Troxel, MD, Medical Director, Board of Governors,
and Louis Marzano, MD, FACOG
Shoulder dystocia (SD) is an uncommon obstetrical complication, occurring in approximately 1 percent of vaginal deliveries. Only 10 to 20 percent of SD cases are associated with brachial plexus injury (BPI). The BPI is usually transient and becomes permanent (pBPI) in only 10 percent of cases (1/5,000 to 1/10,000 deliveries). SD may also be associated with fracture of the clavicle or humerus, postpartum hemorrhage, perineal lacerations, and asphyxia leading to neonatal encephalopathy and/or death.
Most OB malpractice claims result from intrapartum hypoxic events that allegedly caused hypoxic encephalopathy and cerebral palsy. SD with BPI is the second most common reason for suing an obstetrician.
The Doctors Company reviewed closed OB claims from January 2002 through October 2006 and found 59 claims for SD (49 involved BPI, Erb’s palsy, or fracture). No indemnity was paid for 40 claims (although 36 of these incurred defense expenses). Indemnity was paid for 19 claims (one third) and totaled $8,257,500 (an average of $434,600 per paid claim). The legal costs for the 55 paid claims totaled $2,248,300—resulting in an overall cost for SD claims of $10,505,800 (an average of $2,173,600 per year).
The following are the two most common allegations in SD claims:
- “The obstetrician should have recognized that the patient was at risk for SD and either performed or offered the option of cesarean section.” Effective risk management requires identifying women at risk for SD prior to delivery and planning interventions to prevent or limit fetal injury.
- “The BPI occurred because the obstetrician was too forceful in his or her maneuvers during delivery.” This allegation can be defended only if there is thorough documentation in the medical record of precisely what was done during the delivery.
What are the predictors for SD? Risk factors include maternal obesity and diabetes, fetal macrosomia, and previous history of macrosomic birth or SD. The ACOG Practice Bulletin, Number 40, November 2002, suggests the following guidelines:
- With a prior history of SD, the fetal weight, gestational age, glucose tolerance, and severity of prior neonatal injury should be evaluated and the risks and benefits of cesarean section (C/S) discussed.
- Planned C/S may be considered for fetal macrosomia with estimated weights > 5,000 grams in women without diabetes and > 4,500 grams in women with diabetes.
- When SD occurs during delivery, the McRoberts maneuver is a reasonable initial approach.
Unfortunately, the predictive value of maternal obesity/diabetes and fetal macrosomia for SD is low; i.e., only 25 to 50 percent of women meeting these criteria will experience SD. Furthermore, the predictive value for pBPI is even lower, because only 10 to 20 percent of SD infants experience BPI, and only 10 percent of these develop pBPI. Therefore only 1 to 2 percent of infants with SD will have pBPI.
The CALM Shoulder Screen (LMS Medical Systems Inc.) is a new approach to predicting patients at risk for SD with pBPI. It can be used in tandem with the ACOG guidelines. The mother is prescreened at 36 weeks for previous SD, previous baby > 4,000 grams, maternal height < 5 feet, weight gain > 50 pounds, BMI > 35, fundal height > 42 cm, and diabetes. If the answer to any of these questions is yes, an ultrasound estimation of fetal weight is obtained at 37 weeks, and the CALM Shoulder Screen is performed. The screen estimates maternal risk based on computer analysis of parity, gestational age, mother’s height and weight, estimated fetal weight, and presence or absence of diabetes. A risk score is calculated, and, in a graphic personalized report, the patient is assigned to a low-, intermediate-, or high-risk category:
- Women at low risk are reassured.
- Women at intermediate risk are offered the option of cesarean section (the opportunity to choose C/S versus vaginal delivery). However, C/S is not necessarily recommended.
- For women at high risk, C/S is recommended.
A personalized informed-consent form documents that all risk factors have been assessed and discussed with the patient and that treatment options have been presented. If SD occurs, the physician completes an outcomes form to document the delivery events relevant to the management of SD.
In cooperation with The Doctors Company, LMS Medical Systems analyzed our closed SD claims to see how often the ACOG guidelines and CALM Shoulder Screen would have identified the patient as being at risk for SD with pBPI:
- Thirty-two claims contained sufficient data to apply the ACOG criteria (> 4,500 gram fetus + diabetes or > 5,000 gram fetus), and the patient would have been identified as at risk for SD in only five claims (15.6 percent).
- Twenty-seven claims contained the data required for the CALM Screen, and the patient would have been identified as high risk for SD in 11 claims (41 percent), intermediate risk for SD in nine claims (33 percent), and low risk for SD in seven claims (26 percent). The ACOG criteria would have identified only four of these 27 claims (15 percent) as being at risk.
If the CALM high-risk group is thought of as an at-risk group (and the 59 percent false-negative rate supports this), the CALM Shoulder Screen was superior to the ACOG guidelines in identifying women at risk for SD with permanent BPI (CALM sensitivity 41 percent versus ACOG sensitivity 15 percent). However, based on data published elsewhere, CALM’s specificity for the high-risk group is lower (97.4 percent versus 99.9 percent for ACOG), and, due to the low prevalence of SD with pBPI, this may result in performing an unacceptable number of cesarean sections in order to prevent one case of SD with pBPI. This consideration must be evaluated by the obstetrical profession, based on controlled prospective studies and decision-analysis models, to determine if the cesarean delivery rate would increase disproportionately to the reduction in the rate of SD associated with permanent BPI.
Until such studies are published, the following strategies can be considered:
- The physician can plan a detailed prenatal informed-consent discussion with specific reference to the potential for SD. The ACOG recommendations can be reviewed. The CALM Shoulder Screen may be useful as an added tool in predicting higher risk patients, coupled with an explanation of what “at risk” does and doesn’t mean. The risks and benefits of C/S versus vaginal delivery can be discussed.
- The obstetrician can prepare for a possible SD delivery, reviewing the McRoberts maneuver, use of suprapubic pressure, etc.
- Labor and delivery can be alerted to prepare for potential SD at the time of vaginal delivery—with notification of the hospital delivery team (anesthesia, pediatrics, etc.) so that they can prepare as well.
- Rehearsal of the maneuvers utilized during a SD delivery can be considered—as can having a C/S team on standby.
About the Author
David B. Troxel, MD, is medical director of The Doctors Company. Dr. Troxel is clinical professor emeritus in the School of Public Health at the University of California at Berkeley. He is past president of the American Board of Pathology and the California Society of Pathologists.
The Doctor’s Advocate is published by The Doctors Company to advise and inform its members about loss prevention and insurance issues.
The guidelines suggested in this newsletter are not rules, do not constitute legal advice, and do not ensure a successful outcome. They attempt to define principles of practice for providing appropriate care. The principles are not inclusive of all proper methods of care nor exclusive of other methods reasonably directed at obtaining the same results.
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