Maternal morbidity associated with obstetrical maneuvers in shoulder dystocia

OBJECTIVES: To determine whether shoulder dystocia and obstetrical maneuvers used for its relief have detrimental effects on perineum or immediate postpartum outcome. DESIGN: Case-control study. SETTING: Tertiary maternity ward in Marseille, France. POPULATION: A total 140 cases with shoulder dystocia and 280 controls without shoulder dystocia were enrolled by reviewing charts for the period between January 1999 and December 2004. METHODS: Demographic data including obstetrical history, age, height, weight before pregnancy and at the time of delivery, and respective body mass index (BMI) and obstetrical data including analgesic technique, duration of first and second stage of labor were compared in function of outcome and of the type and number of maneuvers used to relieve shoulder dystocia. RESULTS: Resolving shoulder dystocia required one obstetrical maneuver in 41 cases (29.3%) and two obstetrical maneuvers in 48 cases (34.3%). Third-degree tears occurred in one patient in the case group versus five in the control group. No correlation was found between the number of obstetrical maneuvers needed to relieve shoulder dystocia and risk for third-degree tear (OR: 0.8; 95% CI: 0.1-7.6). Mean hemoglobin values were 96.1 g/l in the case group and 96.0 g/l in the control group (p=0.95). There was no difference between the two groups regarding duration of postpartum hospitalization. The incidence of urinary incontinence was similar in the group that underwent obstetrical maneuvers: 4.7% (6/127) and in the control group: 3.7% (13/352). Only two patients reported de novo anal symptoms, both in the control group. CONCLUSION: Shoulder dystocia and obstetrical techniques used for its relief did not result in adverse maternal outcome.     

Complications of shoulder dystocia

Complications of shoulder dystocia are divided into fetal and maternal. Fetal brachial plexus injury (BPI) is the most common fetal complication occurring in 4–40% of cases. BPI has also been reported in abdominal deliveries and in deliveries not complicated by shoulder dystocia. Fractures of the fetal humerus and clavicle occur in about 10.6% of cases of shoulder dystocia and usually heal with no sequel. Hypoxic ischemic brain injury is reported in 0.5–23% of cases of shoulder dystocia. The risk correlates with the duration of head-to-body delivery and is especially increased when the duration is >5 min. Fetal death is rare and is reported in 0.4% of cases. Maternal complications of shoulder dystocia include post-partum hemorrhage, vaginal lacerations, anal tears, and uterine rupture. The psychological stress impact of shoulder dystocia is under-recognized and deserves counseling prior to home discharge.     

Accuracy of estimated fetal weight in shoulder dystocia and neonatal birth injury

OBJECTIVE: This study was undertaken to determine whether there is any difference in the rate of error of estimated fetal weight (EFW) in cases of shoulder dystocia compared with controls. STUDY DESIGN: Women whose delivery was complicated by shoulder dystocia were studied and compared with a control group matched for parity, race, labor type (spontaneous or induced), and birth weight (BW). Accuracy (%) was defined as [(EFW-BW)/BW] x 100. The primary outcome of the study was rate of EFW underestimation error 20% or greater. RESULTS: During the 5-year study period, there were 206 cases of shoulder dystocia that met all study criteria. There was no difference in the number of patients that had EFW underestimation error 20% or greater (shoulder dystocia 9.8% vs control 12.8%; P = .38). There was also no difference in the number of patients that had EFW underestimation error 20% or greater between shoulder dystocia with and without injury (injury 8.3% vs no injury 7.1%; P = .79). CONCLUSION: EFW underestimation error in cases of shoulder dystocia is an infrequent event and does not occur more often than in deliveries without shoulder dystocia.     

Reducing the risk of shoulder dystocia and associated brachial plexus injury

Despite persisting controversy over shoulder dystocia prediction, prevention, and injury causation, the authors find considerable evidence in recent research in the field to recommend additional guidelines beyond the current American College of Obstetricians and Gynecologists and Royal College of Obstetricians and Gynecologists guidelines to improve clinical practice in managing patients at risk for experiencing shoulder dystocia. In this article, the authors offer health care providers information, practical direction, and advice on how to limit shoulder dystocia risk and, more importantly, to reduce adverse outcome risk.     

The risk of shoulder dystocia related permanent fetal injury in relation to birth weight

OBJECTIVE: To examine birth weight related risks of fetal injury in connection with shoulder dystocia. STUDY DESIGN: The investigation was based on a retrospective analysis of 316 fetal neurological injuries associated with deliveries complicated by arrest of the shoulders that occurred across the United States. RESULTS: The study revealed that the distribution of birthweights for the high risk shoulder dystocia population differs from the standard birthweight distribution. The relative difference per birthweight interval is used to adjust an assumed 1:1000 baseline risk of injury due to shoulder dystocia following vaginal deliveries. These adjusted risks show a need to consider new thresholds for elective cesarean delivery. CONCLUSIONS: Current North American and British guidelines, that set 5000 g as minimum estimated fetal weight limit for elective cesarean section in non-diabetic and 4500 g for diabetic gravidas, may expose some macrosomic fetuses to a high risk of permanent neurological damage. The authors present the opinion that the mother, having been informed of the risks of vaginal versus abdominal delivery, should be allowed to play an active role in the critical management decisions.     

After shoulder dystocia: managing the subsequent pregnancy and delivery

Among risk factors for shoulder dystocia, a prior history of delivery complicated by shoulder dystocia is the single greatest risk factor for shoulder dystocia occurrence, with odds ratios 7 to 10 times that of the general population. Recurrence rates have been reported to be as high as 16%. Whereas prevention of shoulder dystocia in the general population is neither feasible nor cost-effective, intervention efforts directed at the particular subgroup of women with a prior history of shoulder dystocia can concentrate on potentially modifiable risk factors and individualized management strategies that can minimize recurrence and the associated significant morbidities and mortality.     

肩难产处理的要点与难点

肩难产是较为常见的产科急症,难以预测并可导致严重的母儿并发症。肩难产处理的关键是设法解除前肩或后肩的嵌顿,这需要规范的操作及团队的协作。本文重点围绕肩难产处理的要点及难点进行阐述。     

Episiotomy versus fetal manipulation in managing severe shoulder dystocia: a comparison of outcomes

OBJECTIVE: In severe shoulder dystocia, when initial maneuvers fail, either episiotomy or fetal manipulation (Rubin, Woods' screw, or posterior arm release) is recommended. We sought to compare maternal and neonatal outcomes between severe shoulder dystocia deliveries managed with episiotomy versus fetal manipulation. STUDY DESIGN: We identified severe shoulder dystocia deliveries from three databases: all shoulder dystocia deliveries (1993-2003 and 1994-1997) from two teaching institutions and litigated cases of shoulder dystocia-associated permanent brachial plexus palsy from multiple U.S. institutions. Pair-wise comparisons were made among three groups of deliveries: those managed by fetal manipulation without episiotomy (fetal manipulation-only), those managed by episiotomy without fetal manipulation (episiotomy-only), and those managed with both (episiotomy + fetal manipulation). Rates of brachial plexus palsy, neonatal depression, and anal sphincter trauma were compared among groups using chi 2 , with significance at P < .05. RESULTS: Among episiotomy-only, 13 of 22 (59.1%) sustained brachial plexus palsy, compared with 20 of 57 (35.1%) among fetal manipulation-only (P = .05). Twenty-eight of 48 (58.3%) in episiotomy + fetal manipulation had brachial plexus palsy, which did not differ from episiotomy-only (P = .95) but was higher than fetal manipulation-only (P = .02), suggesting that the addition of episiotomy conferred no benefit in averting neonatal injury. Anal sphincter trauma was significantly more common among episiotomy-only and episiotomy + fetal manipulation, compared with fetal manipulation-only. CONCLUSION: In severe shoulder dystocia, if fetal manipulation can be performed without episiotomy, severe perineal trauma can be averted without incurring greater risk of brachial plexus palsy.     

Comparing McRoberts' and Rubin's maneuvers for initial management of shoulder dystocia: an objective evaluation

OBJECTIVE: This study was undertaken to objectively compare delivery traction force, fetal neck rotation, and brachial plexus elongation after 3 different initial shoulder dystocia maneuvers: McRoberts', anterior Rubin's, and posterior Rubin's. STUDY DESIGN: We developed a laboratory birthing simulator comprised of a maternal model with a 3-dimensional bony pelvis, an instrumented fetal model, a force-sensing glove, and a computer-based data acquisition system. A single operator performed 30 simulated shoulder dystocia deliveries using standard downward traction after 1 maneuver was performed. Ten deliveries simulated McRoberts' maneuver with fetal shoulders in the anteroposterior diameter. Ten deliveries involved approximately 30-degree oblique rotation of the anterior shoulder with the spine oriented anteriorly (anterior Rubin's maneuver). Ten deliveries involved approximately 30-degree rotation of the posterior shoulder to the opposite oblique pelvic diameter, with the spine oriented posteriorly (posterior Rubin's maneuver). Peak traction force, brachial plexus elongation, and neck rotation were compared between groups using analysis of variance, with P < .05 considered significant. RESULTS: Rubin's maneuvers were found to require less traction force than McRoberts': 16.2 +/- 2.1 lbs for McRoberts' compared with 8.8 +/- 2.2 lbs and 6.5 +/- 1.8 lbs for posterior and anterior Rubin's respectively (P < .0001). Brachial plexus extension was significantly lower after anterior Rubin's maneuver compared with McRoberts' or posterior Rubin's maneuvers. CONCLUSION In a laboratory model of initial maneuvers for shoulder dystocia, anterior Rubin's maneuver requires the least traction for delivery and produces the least amount of brachial plexus tension. Further study is needed to validate these results clinically.     

Permanent brachial plexus injury following vaginal delivery without physician traction or shoulder dystocia

A vaginal delivery that resulted in a permanent brachial plexus injury unassociated with shoulder dystocia or physician traction is reported by the delivering physician. This case demonstrates unequivocally that not all permanent brachial plexus injury at vaginal birth is due to physician traction.     

Prevention of shoulder dystocia related birth injuries: Myths and facts

Traditionally, brachial plexus damage was attributed to excessive traction applied on the fetal head at delivery. Recently, it was proposed that most injuries occur spontaneously in utero. The author has studied the mechanism of neurological birth injuries based on 338 actual cases with special attention to (1) fetal macrosomia; (2) maternal diabetes; and (3) methods of delivery. There was a high coincidence between use of traction and brachial plexus injuries. Instrumental extractions increased the risk exponentially. Erb’s palsy following cesarean section was exceedingly rare. These facts imply that spontaneous neurological injury in utero is extremely rare phenomenon. Literary reports show that shoulder dystocia and its associated injuries increased in the United States several-fold since the introduction of active management of delivery in the 1970’s. Such a dramatic change in a stable population is unlikely to be caused by incidental spontaneous events unrelated to external factors. The cited investigations indicate that brachial plexus damage typically is traction related. The traditional technique which precludes traction is the optimal method for avoiding arrest of the shoulders and its associated neurological birth injuries. Effective prevention also requires meticulous prenatal care and elective abdominal delivery of macrosomic fetuses in carefully selected cases.     

Shoulder dystocia without versus with brachial plexus injury: A case–control study

Objective. To delineate factors that differentiate shoulder dystocia with and without brachial plexus injury (BPI).

Study design. A case–control study culled from an established shoulder dystocia database. Cases of shoulder dystocia-related BPI were identified and matched (1:1) with a control group of shoulder dystocia in which BPI did not result. Odds ratios (OR) and 95% confidence intervals (CI) were calculated.

Results. From 1980 to 2002, there were 89 978 deliveries with 46 cases of dystocia and BPI. The rate of dystocia with BPI was 0.5 per 1000 births and of permanent BPI, 0.9/10 000 deliveries. The two groups were similar for maternal demographics, diabetes, gestational age, induction, use of epidural, the duration of labor, operative vaginal delivery, rate of macrosomia, and maneuvers used to relieve the dystocia. Fracture of the clavicle occurred significantly less often among those without (2%) vs. with BPI (17%; OR 0.10, 95% CI 0.01, 0.88).

Conclusions. Neither antepartum nor intrapartum factors can differentiate the patient who will have shoulder dystocia with vs. without BPI.     

How to predict recurrent shoulder dystocia

OBJECTIVE: Our aim was to determine the rate and risk factors for recurrent shoulder dystocia. STUDY DESIGN: A retrospective analysis of patients diagnosed with shoulder dystocia was performed by searching a computerized database from January 1, 1993, to June 30, 1999 for the following information: (1) vaginal deliveries, either spontaneous or operative, (2) shoulder dystocia, (3) birth weight, (4) duration of second stage of labor, (5) parity, and (6) gestational diabetes. Statistical analyses included chi(2) and t test. RESULTS: There were 39,681 vaginal deliveries with 602 (1.5%) complicated by shoulder dystocia. Sixty-six patients underwent a subsequent vaginal delivery, and 11 (16.7%) experienced another shoulder dystocia. The odds ratio for a recurrent shoulder dystocia was 10.98 (P <.000001). Nine of the 11 patients with recurrent shoulder dystocia compared with 28 of 55 without a recurrence were nulliparous women in their index pregnancy (P <.001). The mean fetal weights were 3885 g in the recurrent dystocia group and 3702 g in the group without recurrence (P <.03). Gestational age, operative delivery, and gestational diabetes were similar in the two groups. CONCLUSION: Factors that appear to increase the recurrence risk of shoulder dystocia include fetal weight and maternal parity. Prior shoulder dystocia is the single greatest predictive factor.     

Prediction of brachial plexus stretching during shoulder dystocia using a computer simulation model

OBJECTIVE: The purpose was to study the impact of maternal endogenous and clinician-applied exogenous delivery forces on brachial plexus stretching during a shoulder dystocia event. STUDY DESIGN: A computer software crash dummy model (MADYMO, version 5.4, TNO Automotive, Delft, The Netherlands) was modified on the basis of established maternal pelvis and fetal anatomic specifications. The brachial plexus was modeled as a spring, with mechanical properties that were based on previously reported experimental data. Increasing amounts of endogenous or exogenous loading forces were applied until delivery of the anterior fetal shoulder occurred. Brachial plexus deformation was assessed as percent stretch in the nerve (Change in length/Original length x 100). RESULTS: With lithotomy positioning, both maternal endogenous and clinician-applied exogenous delivery forces were associated with brachial plexus stretching (15.7% vs 14.0%, respectively). McRoberts positioning reduced needed loading forces for delivery and resulted in 53% less brachial plexus stretch (6.6%). Downward lateral displacement of the fetal head was associated with a 30% increase in brachial plexus stretch (18.2%) compared with axial positioning of the head (14.0%). CONCLUSION: Brachial plexus stretch varied as a result of the load required for delivery, the source of the applied force, pelvic orientation, and fetal head positioning. Maternally derived and clinician-applied delivery forces can both lead to brachial plexus deformation when shoulder dystocia is encountered. The McRoberts maneuver can reduce brachial plexus stretching. Management of fetal head position may also be important in reducing unnecessary brachial plexus stretch.     

Catastrophic shoulder dystocia.

OBJECTIVE: The objective of this paper is to outline in a stepwise fashion a life-saving management sequence for catastrophic shoulder dystocia. METHOD: Five cases of catastrophic shoulder dystocia are analyzed to determine optimal management when confronted with this terrifying obstetric complication. RESULT: The management of these five cases reveals the importance of the early use of uterine relaxing agents and general anesthesia. A second physician is also ideal. The absence of a nuchal cord may result in more favorable outcomes. CONCLUSION: The key to achieving improved outcomes when confronted with catastrophic shoulder dystocia include (1) immediate availability of an operating room and anesthesia personnel, (2) the willingness to use uterine relaxing agents, (3) the availability of a second physician, (4) an understanding of the best sequence of remedial measures to follow, (5) total delivery within 12-13 min of the delivery of the head (almost impossible when the delivery process begins in a birthing room) and (6) a cesarean room should be considered for delivery of all massively obese women.