Shoulder dystocia: an evidence-based evaluation of the obstetric nightmare

Fetal Growth Biometry as Predictors of Shoulder Dystocia in a Low-Risk Obstetrical Population

OBJECTIVE

 This study aimed to evaluate fetal biometrics as predictors of shoulder dystocia (SD) in a low-risk obstetrical population.

STUDY DESIGN

 Participants were enrolled as part of a U.S.-based prospective cohort study of fetal growth in low-risk singleton gestations (n = 2,802). Eligible women had liveborn singletons ≥2,500 g delivered vaginally. Sociodemographic, anthropometric, and pregnancy outcome data were abstracted by research staff. The diagnosis of SD was based on the recorded clinical impression of the delivering physician. Simple logistic regression models were used to examine associations between fetal biometrics and SD. Fetal biometric cut points, selected by Youden's J and clinical determination, were identified to optimize predictive capability. A final model for SD prediction was constructed using backward selection. Our dataset was randomly divided into training (60%) and test (40%) datasets for model building and internal validation.

RESULTS

 A total of 1,691 women (98.7%) had an uncomplicated vaginal delivery, while 23 (1.3%) experienced SD. There were no differences in sociodemographic or maternal anthropometrics between groups. Epidural anesthesia use was significantly more common (100 vs. 82.4%; p = 0.03) among women who experienced SD compared with those who did not. Amniotic fluid maximal vertical pocket was also significantly greater among SD cases (5.8 ± 1.7 vs. 5.1 ± 1.5 cm; odds ratio = 1.32 [95% confidence interval: 1.03,1.69]). Several fetal biometric measures were significantly associated with SD when dichotomized based on clinically selected cut-off points. A final prediction model was internally valid with an area under the curve of 0.90 (95% confidence interval: 0.81, 0.99). At a model probability of 1%, sensitivity (71.4%), specificity (77.5%), positive (3.5%), and negative predictive values (99.6%) did not indicate the ability of the model to predict SD in a clinically meaningful way.

CONCLUSION

 Other than epidural anesthesia use, neither sociodemographic nor maternal anthropometrics were significantly associated with SD in this low-risk population. Both individually and in combination, fetal biometrics had limited ability to predict SD and lack clinical usefulness.

KEY POINTS

· SD unpredictable in low-risk women.. · Fetal biometry does not reliably predict SD.. · Epidural use associated with increased SD risk.. · SD prediction models clinically inefficient..

Antenatal risk score for prediction of shoulder dystocia with focus on fetal ultrasound data

BACKGROUND

Shoulder dystocia is one of the most threatening complications during delivery, and although it is difficult to predict, individual risk should be considered when counseling for mode of delivery.

OBJECTIVE

This study aimed to develop and validate a risk score for shoulder dystocia based on fetal ultrasound and maternal data from 15,000 deliveries.

STUDY DESIGN

Data were retrospectively obtained of deliveries in 3 tertiary centers between 2014 and 2017 for the derivation cohort and between 2018 and 2020 for the validation cohort. Inclusion criteria were singleton pregnancy, vaginal delivery in cephalic presentation at ≥37+0 weeks' gestation, and fetal biometry data available within 2 weeks of delivery. Independent predictors were determined by multivariate regression analysis in the derivation cohort, and a score was developed on the basis of the effect of the predictors.

RESULTS

The derivation cohort consisted of 7396 deliveries with a 0.91% rate of shoulder dystocia, and the validation cohort of 7965 deliveries with a 1.0% rate of shoulder dystocia. Among all women, 13.8% had diabetes mellitus, and 12.1% were obese (body mass index ≥30 kg/m2). Independent risk factors in the derivation cohort were: estimated fetal weight ≥4250 g (odds ratio, 4.27; P=.002), abdominal-head-circumference ≥2.5 cm (odds ratio, 3.96; P<.001), and diabetes mellitus (odds ratio, 2.18; P=.009). On the basis of the strength of effect, a risk score was developed: estimated fetal weight ≥4250 g=2, abdominal-head-circumference ≥2.5 cm=2, and diabetes mellitus=1. The risk score predicted shoulder dystocia with moderate discriminatory ability (area under the receiver-operating characteristic curve, 0.69; P<.001; area under the receiver-operating characteristic curve, 0.71; P<.001) and good calibration (Hosmer-Lemeshow goodness-of-fit; P=.466; P=.167) for the derivation and validation cohorts, respectively. With 1 score point, 16 shoulder dystocia cases occurred in 1764 deliveries, with 0.6% shoulder dystocia incidence and a number needed to treat with cesarean delivery to avoid 1 case of shoulder dystocia of 172 (2 points: 38/1809, 2.1%, 48; 3 points: 18/336, 5.4%, 19; 4 points: 10/96, 10.5%, 10; and 5 points: 5/20, 25%, 4); 40.8% of the shoulder dystocia cases occurred without risk factors.

CONCLUSION

The presented risk score for shoulder dystocia may act as a supplemental tool for the clinical decision-making regarding mode of delivery. According to our score model, in pregnancies with a score ≤2, meaning having solely estimated fetal weight ≥4250 g, or abdominal-head-circumference ≥2.5, or diabetes mellitus, cesarean delivery for prevention of shoulder dystocia should not be recommended because of the high number needed to treat to avoid 1 case of shoulder dystocia. Conversely, in patients with a score of ≥4 with or without diabetes mellitus, cesarean delivery may be considered. However, in 40% of the shoulder dystocia cases, no risk factors had been present.

Antenatal risk prediction of shoulder dystocia: influence of diabetes and obesity: a multicenter study

PURPOSE

To estimate the risk of shoulder dystocia (SD) in pregnancies with/without maternal diabetes or obesity; to identify antenatal maternal and fetal ultrasound-derived risk factors and calculate their contributions.

METHODS

A multicenter retrospective analysis of 13,428 deliveries in three tertiary hospitals (2014-2017) with fetal ultrasound data ≤ 14 days prior to delivery (n = 7396).

INCLUSION CRITERIA

singleton pregnancies in women ≥ 18 years old; vertex presentation; vaginal delivery at ≥ 37 weeks of gestation. Estimated fetal weight (EFW) and birth weight (BW) were categorized by steps of 250 g. To evaluate risk factors, a model was performed using ultrasound data with SD as the dependent variable.

RESULTS

Diabetes was present in 9.3%; BMI ≥ 30 kg/m² in 10.4% and excessive weight gain in 39.8%. The total SD rate was 0.9%, with diabetes 2.0% and with obesity 1.9%. These increased with BW 4250-4499 g compared to 4000-4249 g in women with diabetes (12.1% vs 1.9%, P = 0.010) and without (6.1% vs 1.6%, P < 0.001) and at the same BW threshold for women with obesity (9.6% vs 0.6%, P = 0.002) or without (6.4% vs 1.8%, P < 0.001). Rates increased similarly for EFW at 4250 g and for AC-HC at 2.5 cm. Independent risk factors for SD were EFW ≥ 4250 g (OR 3.8, 95% CI 1.5-9.4), AC-HC ≥ 2.5 cm (OR 3.1, 95% CI 1.3-7.5) and diabetes (OR 2.2, 95% CI 1.2-4.0). HC/AC ratio, obesity, excessive weight gain and labor induction were not significant.

CONCLUSION

Independent of diabetes, which remains a risk factor for SD, a significant increase may be expected if the EFW is ≥ 4250 g and AC-HC is ≥ 2.5 cm.

Shoulder Dystocia during Delivery and Long-Term Neurological Morbidity of the Offspring

OBJECTIVE

The study aimed to evaluate risk factors and implications of shoulder dystocia (SD) on the neurological outcome of successfully delivered offspring.

STUDY DESIGN

This is a cohort analysis including 207,571 deliveries. Risk factors for SD were evaluated using general estimation equation multivariable analyses. Offspring hospitalization incidence up to age 18 years due to neurological conditions was compared between both groups. Kaplan-Meyer curve was used to assess the cumulative hospitalization incidence. Cox proportional hazards model was used to control for confounders.

RESULTS

SD complicated 0.2% (n = 353) of deliveries included in the study (n = 207,571). Risk factors for SD were fetal macrosomia, maternal diabetes mellitus, male gender, and advanced maternal age (p < 0.05 for all). Higher perinatal mortality was observed among SD cases (2.8 vs. 0.4%, p < 0.001). In most of the investigated neurological conditions no significant differences were found between the groups. Comparable rates of cumulative neurological-related hospitalization were observed (log rank p-value = 0.342) as well as lack of association between SD and neurological hospitalization (adjusted HR = 0.73; 95% CI 0.36-1.47; p = 0.381) when controlled for gestational age.

CONCLUSION

Risk factors for SD are macrosomia, diabetes mellitus, male gender, and advanced maternal age. SD is not associated with long-term neurological morbidity of the offspring.

Axillary traction: An effective method of resolving shoulder dystocia

BACKGROUND

At Counties Manukau Health in Auckland, New Zealand, axillary traction is being used when an internal manoeuvre is required for resolution of shoulder dystocia.

AIMS

This study presents the outcomes for mother and baby from use of axillary traction and other internal manoeuvres.

MATERIALS AND METHODS

Retrospective review of the clinical records of mother and baby for all labours complicated by shoulder dystocia was carried out for an eight-year period. Maternal and neonatal information were compared for the three cohorts of the first internal manoeuvre documented: axillary traction, posterior arm delivery and rotational manoeuvres.

RESULTS

There were 226 women who required the use of internal manoeuvres with no significant differences in age, body mass index, parity, ethnicity, diabetes incidence, induction and augmentation of labour rates, length of the first stage and birth weight between the cohorts. Axillary traction was the first internal manoeuvre used for 119 (52.7%) with a success rate of 95.8%. Posterior arm delivery was used first for 49 (21.7%) women with a success rate of 85.7%. Rotational manoeuvres were used first for 58 (25.7%) women with a statistically inferior success rate of 48.3%. There was no significant difference in the maternal and neonatal complication rates between the cohorts.

CONCLUSION

Axillary traction has been utilised as the first internal manoeuvre for a large number of women with a higher success rate than other internal manoeuvres without any increase in maternal or neonatal morbidity. It is recommended that this be the first internal manoeuvre attempted when shoulder dystocia occurs.

The Association of Clavicle Fracture With Brachial Plexus Birth Palsy

PURPOSE

Shoulder dystocia is the strongest known risk factor for brachial plexus birth palsy (BPBP). Fractures of the clavicle are known to occur in the setting of shoulder dystocia. It remains unknown whether a clavicle fracture that occurs during a birth delivery with shoulder dystocia increases the risk of BPBP or, alternatively, is protective. The purpose of this study was to use a large, national database to determine whether a clavicle fracture in the setting of shoulder dystocia is associated with an increased or decreased risk of BPBP.

MATERIALS AND METHODS

The 1997 to 2012 Kids' Inpatient Database (KID) was analyzed for this study. International Classification of Diseases, Ninth Revision (ICD-9) codes were used to identify newborns diagnosed with shoulder dystocia and BPBP as well as a concurrent fracture of the clavicle. Newborns with shoulder dystocia were stratified into 2 groups: dystocia without a clavicle fracture and dystocia with a clavicle fracture. Multivariable logistic regression was used to quantify the risk for BPBP among shoulder dystocia subgroups.

RESULTS

The dataset included 5,564,628 sample births extrapolated to 23,385,597 population births over the 16-year study period. A BPBP occurred at a rate of 1.2 per 1,000 births. Shoulder dystocia complicated 18.8% of births with a BPBP. A total of 7.84% of newborns with a BPBP also sustained a clavicle fracture. Births with shoulder dystocia and a clavicle fracture incurred BPBP at a rate similar to that for newborns with shoulder dystocia and no fracture (9.82% vs 11.77%). Shoulder dystocia without a concurrent clavicle fracture was an independent risk factor for BPBP (odds ratio, 112.1; 95% confidence interval, 103.5-121.4). Those with shoulder dystocia and clavicle fracture had a risk for BPBP comparable with those with shoulder dystocia but no fracture (odds ratio, 126.7 vs 112.1).

CONCLUSIONS

This population-level investigation suggests that, among newborns with shoulder dystocia, clavicle fracture is not associated with a significant change in the risk of BPBP.

TYPE OF STUDY/LEVEL OF EVIDENCE

Prognostic II.

Precipitous Labor and Emergency Department Delivery

A precipitous delivery can be among the most stressful events an emergency physician encounters. The physician must assess 2 patients (mother and fetus) and be prepared to manage a variety of complications that may arise during delivery. A majority of precipitous deliveries result in good outcomes for both mother and baby, but emergency physicians must be prepared to manage feared complications, such as tight nuchal cords, shoulder dystocia, and breech presentation. An understanding of the labor process as well as advanced planning can help decrease the stress and chaos inherent to any precipitous delivery.

Obesity in pregnancy: a comparison of four national guidelines

BACKGROUND

Obesity in pregnancy has become one of the most important challenges in obstetrical care given its prevalence and potential adverse impact on both mother and fetus. The primary objective of this descriptive review is to identify common themes and distinctions within the current recommendations for maternal obesity in the most updated version of four published national guidelines.

METHODS

We reviewed the following guidelines for obesity in pregnancy: American College of Obstetricians and Gynecologists (ACOG) 2015, Royal Australian and New Zealand College of Obstetricians and Gynecologists (RANZCOG) 2013, Royal College of Obstetrics and Gynecology (RCOG) 2010, and Society of Obstetrics and Gynecologists of Canada (SOGC) 2010.

RESULTS

There were no major contradictions between the guidelines, however, variations did exist. Recognition of overweight and obese populations prenatally was uniformly emphasized, so that appropriate nutrition and exercise counseling could be provided prior to pregnancy. Obesity in pregnancy was consistently defined as a body mass index of 30 kg/m² or more, and weight gain recommendations were in line with the Institute of Medicine guidelines. Counseling patients regarding the specific maternal and fetal complications in pregnancy, delivery, and postpartum which are associated with obesity was consistently emphasized. Most guidelines recommended early screening for gestational diabetes, however, specific details were not provided. All guidelines stressed the importance of available resources in clinics and the operating room specific to the obese population. Disparities were found regarding recommendations for high-dose folic acid, vitamin D supplementation, and low-dose aspirin. Thromboprophylaxis is a matter of debate, with most guidelines recommending use on an individual patient basis.

CONCLUSIONS

In general, the guidelines emphasized the importance of counseling women regarding the risks associated with obesity in pregnancy, and stressed the necessity of screening for these adverse outcomes. Initiatives to develop common terminology and reporting of outcomes in women's health are important for the development of cohesive and uniform recommendations for patient care. Disparities existed with respect to management strategies and where the further research and systematic reviews should be targeted, to allow clinicians to provide an appropriate obstetrical care pathway for obese women.

Effect of the use of a video tutorial in addition to simulation in learning the maneuvers for shoulder dystocia

The development of video tutorials is flourishing and may make it possible to maintain knowledge learned during instruction with simulation. The aim of this study was to assess the effect of adding a video tutorial to a lecture and simulation for learning the maneuvers and protocol for the management of shoulder dystocia. Student midwives and medical students attended a lecture class including instruction about maneuvers and a presentation of an algorithm for the management of shoulder dystocia. They were randomized into two groups. The video group was reminded every two weeks to watch a short tutorial. The control group was reminded to consult the slide show. At the end of two months, they were evaluated by graders. The practice, theory, and global scores of the students in the video group were significantly higher than those of the students in the control group (14.8 vs. 10.4; 5.6 vs. 3.4; and 9.3 vs. 7.0, P<0.001). The scores for the video group improved at the second simulation session, compared with the first (14.8 vs. 9.9; 5.6 vs. 2.9; and 9.3 vs. 7, P<0.001). The addition of a video tutorial improved learning compared to a standard lecture and simulation session alone.

Effect of high-fidelity shoulder dystocia simulation on emergency obstetric skills and crew resource management skills among residents

OBJECTIVE

To determine the effect of a simulation training program for residents in obstetrics and gynecology in terms of technical and nontechnical skills for the management of shoulder dystocia.

METHODS

A prospective study was performed at a center in Italy in April-May 2015. Thirty-two obstetrics and gynecology residents were divided into two groups. Residents in the control group were immediately exposed to an emergency shoulder dystocia scenario, whereas those in the simulation group completed a 2-hour training session with the simulator before being exposed to the scenario. After 8weeks, the residents were again exposed to the shoulder dystocia scenario and reassessed. Participants were scored on their demonstration of technical and nontechnical skills.

RESULTS

In the first set of scenarios, the mean score was higher in the simulation group than the control group in terms of both technical skills (P=0.008) and nontechnical skills (P<0.001). This difference was retained after 8weeks.

CONCLUSION

High-fidelity simulation programs could be used for the training of residents in obstetrics and gynecology to diagnose and manage obstetric emergencies such as shoulder dystocia.

[The Jacquemier's maneuver: An overview of midwives knowledge and practices in a third level maternity hospital]

OBJECTIVES

Shoulder dystocia is an uncommon but serious complication occurring in 0.2 to 3% of deliveries. We carried out a study in order to assess the midwives experience, knowledge and practices on shoulder dystocia, at the maternity hospital of Saint-Denis, Reunion Island.

METHODS

The first part is a confidential questionnaire addressed to midwives working in the delivery unit. The second part is a retrospective desk review of shoulders dystocia which occurred from 2004 to 2014.

RESULTS

(1) The population was made up of 28 midwives, having between 1 to 27 years of experience. Seventy-five percent of them had been faced with shoulder dystocia, and 62% had realized Jacquemier's maneuver. However, only 25% received this maneuver training. Less than a third of them answered correctly to at least 7 from the 8 theoretical questions about the Jacquemier's maneuver. (2) We studied 34 shoulders dystocia, occurring between 36+5 to 41+2 gestational weeks, mostly with no risk factors found. Mac Roberts' maneuver is used as first-line in 88% of situations. Jacquemier's maneuver is used in 52.9% of cases (5.9% as first-line, 47% as second-line). In 26.4% of situations, the midwife is not able to reduce the dystocia. She usually carries out a combination of maneuvers. The gynecologist is asked only for 23.5% of dystocia and he usually uses Jacquemier's maneuver (70% of situations).

CONCLUSION

The Jacquemier's maneuver is rarely practiced (uncommon situation, lack of training). Simulation trainings should be put in place, because neonatal sequels can be avoided.

[Neonatal complications related to shoulder dystocia]

OBJECTIVE

To describe neonatal complications related to shoulder dystocia.

METHODS

This systematic evidence review is based on PubMed search, Cochrane library and experts' recommendations.

RESULTS

The risks of brachial plexus birth injury, clavicle and humeral fracture, perinatal asphyxia, hypoxic-ischemic encephalopathy and perinatal mortality are increased after shoulder dystocia. The medical team should be able to provide neonatal resuscitation in the delivery room in case of perinatal asphyxia following shoulder dystocia, according to national and international guidelines. The initial clinical examination should search for complications such as brachial plexus birth injury or clavicle fracture.

CONCLUSION

The risk of perinatal complications is increased in newborn after shoulder dystocia. The medical team should be able to manage these complications.

[Epidemiology of shoulder dystocia]

OBJECTIVES

To synthetize the available evidence regarding the incidence and risk factors of shoulder dystocia (SD).

METHODS

Consultation of the Medline database, and of national guidelines.

RESULTS

Shoulder dystocia is defined as a vaginal delivery that requires additional obstetric manoeuvres to deliver the foetus after the head has delivered and gentle traction has failed. With this definition, the incidence of SD in population-based studies is about 0.5-1% of vaginal deliveries. Many risk factors have been described but most associations are not independent, or have not been constantly found. The 2 characteristics consistently found as independent risk factors for SD in the literature are previous SD (incidence of SD of about 10% in parturients with previous SD) and foetal macrosomia. Maternal diabetes and obesity also are associated with a higher risk of SD (2 to 4 folds) but these associations may be completely explained by foetal macrosomia. However, even factors independently and constantly associated with SD do not allow a valid prediction of SD because they are not discriminant; 50 to 70% of SD cases occur in their absence, and the great majority of deliveries when they are present is not associated with SD.

CONCLUSION

Shoulder dystocia is defined by the need for additional obstetric manoeuvres to deliver the foetus after the head has delivered and gentle traction has failed, and complicates 0.5-1% of vaginal deliveries. Its main risk factors are previous SD and macrosomia, but they are poorly predictive. SD remains a non-predictable obstetrics emergency. Knowledge of SD risk factors should increase the vigilance of clinicians in at-risk contexts.

Shoulder dystocia: risk factors, predictability, and preventability

Shoulder dystocia remains an unpredictable obstetric emergency, striking fear in the hearts of obstetricians both novice and experienced. While outcomes that lead to permanent injury are rare, almost all obstetricians with enough years of practice have participated in a birth with a severe shoulder dystocia and are at least aware of cases that have resulted in significant neurologic injury or even neonatal death. This is despite many years of research trying to understand the risk factors associated with it, all in an attempt primarily to characterize when the risk is high enough to avoid vaginal delivery altogether and prevent a shoulder dystocia, whose attendant morbidities are estimated to be at a rate as high as 16-48%. The study of shoulder dystocia remains challenging due to its generally retrospective nature, as well as dependence on proper identification and documentation. As a result, the prediction of shoulder dystocia remains elusive, and the cost of trying to prevent one by performing a cesarean delivery remains high. While ultimately it is the injury that is the key concern, rather than the shoulder dystocia itself, it is in the presence of an identified shoulder dystocia that occurrence of injury is most common. The majority of shoulder dystocia cases occur without major risk factors. Moreover, even the best antenatal predictors have a low positive predictive value. Shoulder dystocia therefore cannot be reliably predicted, and the only preventative measure is cesarean delivery.

Shoulder dystocia: simulation and a team-centered protocol

Shoulder dystocia is an obstetric emergency that has been reported to occur in 0.2-3% of all vaginal deliveries. Several characteristics of shoulder dystocia make it a particular challenge to manage effectively. It is relatively infrequent, the diagnosis cannot be made according to a single objective criterion that can be recognized to exist by all members of the care team who are present, it is unpredictable, and there is the need for coordinated actions of all members of the health care team who have come together on the day of the delivery and may not have worked together before or specifically during a shoulder dystocia. In general, there is evidence from different medical disciplines that checklists/protocols and simulation may be used to enhance team performance. There is also some evidence, albeit limited, that such techniques may be used to improve shoulder dystocia outcomes.

Precipitous and difficult deliveries

Any delivery in the emergency department is considered a precipitous birth and is an anxiety-producing event. Many deliveries proceed without incident. However, the emergency physician must be prepared for several dreaded scenarios, such as nuchal cord, shoulder dystocia, and breech birth. This article reviews the basics, complications, and management of such deliveries.

Severe brachial plexus palsy in women without shoulder dystocia

OBJECTIVE

Neonatal brachial plexus palsy frequently is described in conjunction with shoulder dystocia complicating a vaginal delivery. In this study, we present a series of cases of severe brachial plexus palsy that occurred without shoulder dystocia.

METHODS

Cases were identified from deliveries at the Los Angeles County and University of Southern California Medical Center. Various maternal and neonatal characteristics were analyzed.

RESULTS

Eight cases without shoulder dystocia but with severe brachial plexus palsy requiring neonatal intensive care unit admission were identified. None of the patients had maternal diabetes, previous shoulder dystocia, previous macrosomia, or labor induction. The mean second stage of labor was normal (2.15 ± 1.93), as was the mean birth weight (3,514 ± 1,043). One case required cesarean delivery.

CONCLUSION

These results demonstrate that severe brachial plexus palsy occurs in women without shoulder dystocia and without identifiable risk factors.

Association of fetal cranial shape with shoulder dystocia

OBJECTIVE

To evaluate whether fetal cranial shape is related to shoulder dystocia.

METHODS

We compared shoulder dystocia cases (n = 18) with controls (normal vaginal deliveries, n = 18) in a retrospective matched-pairs observational study. Subjects were matched for known maternal and fetal risk factors and then evaluated for fetal biometric differences, which were measured by ultrasound near delivery. We tested multivariable risk models to predict shoulder dystocia by logistic regression.

RESULTS

Cases had a smaller estimated occipitofrontal diameter (OFD) (P = 0.02) and a larger biparietal diameter/estimated OFD ratio (P = 0.003). A multivariable model including estimated fetal weight, estimated OFD, maternal weight and diabetes mellitus had sensitivity and specificity of 86% and 95%, respectively, and positive and negative likelihood ratios of 18.9 and 0.15, respectively. Estimated OFD significantly increased the predictive value of the model.

CONCLUSION

A small estimated OFD is a risk factor for shoulder dystocia in the presence of other significant risk factors. A multivariable model including estimated OFD can predict shoulder dystocia in a clinically useful range.

Complications of labor and delivery: shoulder dystocia

This article reviews one of the less common but most dreaded complications of labor and delivery, shoulder dystocia, an infrequent but potentially devastating event that results from impaction of the fetal shoulders in the maternal pelvis. Shoulder dystocia occurs most commonly in patients without identified risk factors, and can result in both maternal and fetal morbidity. Because the vast majority of cases of shoulder dystocia are unpredictable, obstetric care providers must be prepared to recognize dystocia and respond appropriately in every delivery. Detailed documentation is essential after any delivery complicated by shoulder dystocia.

Outcomes associated with introduction of a shoulder dystocia protocol

The objective of this study was to assess outcomes that are associated with the implementation of a shoulder dystocia protocol that is focused on team response. We identified women who had a shoulder dystocia during 3 time periods: 6 months before (period A), 6 months during (period B), and 6 months after (period C) the institution of a shoulder dystocia protocol. Documentation and health outcomes were compared among the time periods. During the study period, 254 women (77, 100, and 77 in periods A, B, and C, respectively) had a shoulder dystocia. There were no differences among study periods in patient characteristics. However, complete and consistent documentation increased (14% to 50% to 92%; P < .001), and brachial plexus palsy that was diagnosed at delivery (10.1% to 4.0% to 2.6%; P = .03) and at neonatal discharge (7.6% to 3.0% to 1.3%; P = .04) declined.

Critical analysis of risk factors for shoulder dystocia

OBJECTIVE

The study was aimed to define trends, risk factors and perinatal outcome associated with shoulder dystocia (SD).

METHODS

A population-based study comparing all singleton deliveries with and without SD was conducted. Statistical analysis was performed using multiple logistic regression analysis.

RESULTS

Shoulder dystocia complicated 0.2% (n = 451) of all deliveries included in the study (n = 240,189). The rate of SD declined from 0.4% in 1988 to 0.13% in 2009. Independent risk factors for SD in a multivariable analysis were fetal macrosomia (birth-weight ≥ 4 kg; OR = 16.1; 95% CI 13.2-19.6, P < 0.001), failure of labor to progress during the second stage (OR = 2.4; 95% CI 1.5-3.7, P < 0.001), diabetes mellitus (OR = 1.8; 95% CI 1.4-2.3, P < 0.001) and advanced maternal age (years, OR = 1.02; 95% CI 1.001-1.03, P = 0.029). Perinatal mortality was significantly higher after SD as compared to the comparison group (6.2 vs. 1.4%, P <0.001). Another multivariable analysis, with perinatal mortality as the outcome variable, controlling for confounders such as maternal age, gestational age, diabetes mellitus, etc. was constructed; SD was noted as an independent risk factor for perinatal mortality (adjusted OR = 11.1; 95% CI 7.2-17.1, P < 0.001).

CONCLUSIONS

Shoulder dystocia, associated with macrosomia, labor dystocia, diabetes mellitus, and advanced maternal age, is an independent risk factor for perinatal mortality. In an era of increased rate of cesarean deliveries, and perhaps increased accuracy of birth weight estimation, the rate of shoulder dystocia gradually declines.

Shoulder dystocia: a qualitative exploration of what works

OBJECTIVE

to explore expert practitioners' methods of managing shoulder dystocia.

DESIGN AND SETTING

a qualitative interpretive study enabled a descriptive, hermeneutic analysis of data collected. Data were collected via tape recorded interviews, transcribed and analysed to explore themes and meanings.

PARTICIPANTS

five clinicians (four midwives and one obstetrician) who have significant experience in the management of shoulder dystocia and work in high risk maternity practice.

KEY FINDINGS

IMPLICATIONS FOR PRACTICE

the results of this study demonstrate that the actions to be taken in the event of shoulder dystocia should be further examined and possibly reviewed. The three simple steps of McRoberts Manoeuvre - Suprapubic Pressure - Axillary Traction could revolutionise the way in which shoulder dystocia is managed.

Risk of shoulder dystocia in second delivery: does a history of shoulder dystocia matter?

OBJECTIVE

Our aim was to estimate the relative and absolute risk of shoulder dystocia in the second delivery according to history of shoulder dystocia and offspring birthweight.

STUDY DESIGN

A retrospective cohort study including all women in Norway with 2 consecutive singleton vaginal deliveries with fetus in cephalic presentation, during the period 1967-2005 (n = 537,316).

RESULTS

In the second delivery shoulder dystocia occurred in 0.8% of all women. In women with a prior shoulder dystocia the recurrence risk was 7.3%. Most cases of shoulder dystocia in second delivery were in women without such history (96.2%). Offspring birthweight was the most important risk factor for shoulder dystocia in second delivery: crude odds ratio, 292.9 (95% confidence interval, 237.8-360.7) comparing birthweight > 5000 g with 3000-3499 g.

CONCLUSION

Prior shoulder dystocia increased the risk of shoulder dystocia in the second delivery. However, offspring birthweight was by far the most important risk factor.

[Shoulder dystocia: a ten-year descriptive study in a level-III maternity unit]

OBJECTIVE

Shoulder dystocia is one of the most dreadful complications of vaginal deliveries. The aim of this observational study was to evaluate risk factors of dystocia, maternal and neonatal complications and recurrent risk factors.

PATIENTS AND METHODS

Sixty-six cases of shoulder dystocia occurring between January 1998 and August 2008 in our university hospital were identified. Demographic data, labor management, management of the shoulder dystocia and neonatal outcome were recorded.

RESULTS

The incidence of shoulder dystocia was 0.3%. Multiparity, weight gain greater than 12 kg, and post-term delivery were more present in our study group. McRoberts' manoeuver and symphyseal pressure were first realised. Brachial plexus injuries affected 9% of neonates with skeletal fractures in 7.5% of cases. Maternal morbidity was evaluated at about 8%. Twenty per cent had a recurrent shoulder dystocia.

DISCUSSION AND CONCLUSION

Shoulder dystocia is an obstetric emergency which requires a prompt management of trained personnel. Despite the difficulty of being able to prevent shoulder dystocia, training the obstetric staff could probably improve management of shoulder dystocia.

Shoulder dystocia in a Jamaican cohort

OBJECTIVE

To assess the risk factors for shoulder dystocia in Jamaica.

METHODS

A retrospective cohort analysis of all cases of shoulder dystocia, and birth weight-matched controls identified from January 1, 2000 to December 31, 2004. Multiple factors were analyzed individually and in combination to identify risk factors.

RESULTS

The incidence of shoulder dystocia was 0.83%. Nulliparity, a first stage of labor greater than 7 hours, a second stage lasting more than 1 hour, and use of oxytocin augmentation were found to be statistically significant factors with unadjusted odds ratios (95% confidence interval) of 1.78 (0.86-3.34), 1.89 (0.91-3.94), 2.78 (0.24-31.47), and 1.56 (0.77-3.15), respectively. The incidence of shoulder dystocia decreased as parity increased when adjusted for age.

CONCLUSION

Individual risk factors for shoulder dystocia remain obscure. The nulliparous pelvis, when controlled for neonatal weight, was associated with a statistically increased risk of shoulder dystocia; this risk decreased with increasing parity.

[Severe shoulder dystocia: study of 14 cases treated by Jacquemier's maneuver]

OBJECTIVE

Shoulder dystocia is a dreadful complication of vaginal deliveries since it can be responsible of brachial plexus palsies and even neonatal deaths. Unlike most studies, we defined shoulder dystocia as the enclosing of fetal shoulders above the superior strait (cavity station of 1cm) and situations being resolved only by delivery of the posterior arm (Jacquemier's maneuver). The purpose of this study was to analyze cases of shoulder dystocia in terms of maternal and neonatal complications and to compare risk factors with those identified in the literature.

MATERIAL AND METHODS

We conducted a retrospective study of 14 cases of severe shoulder dystocia (SSD) which occurred at our hospital between January 1995 and January 2007. TSD was diagnosed in the absence of engagement of both fetal shoulders requiring recourse to Jacquemier's maneuver for delivery. Any gestational diabetes, abnormal progression of labour, suspicion or existence of fetal macrosomia, instrumental delivery, and neonatal complications were noted.

RESULTS

The incidence of SSD was around 1 per thousand. Multiparity, weight gain greater than 15kg and gestational diabetes were moderately present in our study group. Only 20% of neonates were macrosomic and 50% had a birth-weight of less than 4000g. In 80% of cases, an instrumental extraction was practised. Brachial plexus injuries affected 20% of neonates, no fracture was observed, one child died following an unresolved SSD.

CONCLUSION

This series shows that the incidence of SSD is rare and difficultly predictable even though identified risk factors exist. However, an instrumental extraction seems frequently associated with SSD and any extraction should take into account the presence of known risk factors. In spite of the severity of our cases of shoulder dystocia, complications found seemed to be similar to those observed in the literature.

Prediction of risk for shoulder dystocia with neonatal injury

OBJECTIVE

The purpose of this study was to develop a predictive model of risk for shoulder dystocia (ShD) with injury.

STUDY DESIGN

Medical records in 3 urban university teaching hospitals were reviewed to identify and characterize 498 cases of ShD, including 90 with neonatal injury and a comparison group with of 622 with vaginal delivery (VgD) without ShD. The data were subjected to logistic regression modeling to find the best combination of variables to discriminate between the injury and VgD groups.

RESULTS

The best model included birth weight in combination with maternal height and weight as well as gestational age and parity. A score over 0.5 detected 50.7% of the shoulder dystocia cases with brachial plexus injury along with a false positive rate of 2.7%.

CONCLUSION

Using a statistical model it is possible to identify adverse combinations of factors that are associated with ShD and neonatal injury along with a relatively low false positive rate.

Shoulder dystocia: the unpreventable obstetric emergency with empiric management guidelines

OBJECTIVE

Much of our understanding and knowledge of shoulder dystocia has been blurred by inconsistent and scientific studies that are of limited scientific quality. In an evidence-based format, we sought to answer the following questions: (1) Is shoulder dystocia predictable? (2) Can shoulder dystocia be prevented? (3) When shoulder dystocia does occur, what maneuvers should be performed? and (4) What are the sequelae of shoulder dystocia?

STUDY DESIGN

Electronic databases, including PUBMED and the Cochrane Database, were searched using the key word "shoulder dystocia." We also performed a manual review of articles included in the bibliographies of these selected articles to further define articles for review. Only those articles published in the English language were eligible for inclusion.

RESULTS

There is a significantly increased risk of shoulder dystocia as birth weight linearly increases. From a prospective point of view, however, prepregnancy and antepartum risk factors have exceedingly poor predictive value for the prediction of shoulder dystocia. Late pregnancy ultrasound likewise displays low sensitivity, decreasing accuracy with increasing birth weight, and an overall tendency to overestimate the birth weight. Induction of labor for suspected fetal macrosomia has not been shown to alter the incidence of shoulder dystocia among nondiabetic patients. The concept of prophylactic cesarean delivery as a means to prevent shoulder dystocia and therefore avoid brachial plexus injury has not been supported by either clinical or theoretic data. Although many maneuvers have been described for the successful alleviation of shoulder dystocia, there have been no randomized controlled trials or laboratory experiments that have directly compared these techniques. Despite the introduction of ancillary obstetric maneuvers, such as McRoberts maneuver and a generalized trend towards the avoidance of fundal pressure, it has been shown that the rate of shoulder-dystocia associated brachial plexus palsy has not decreased. The simple occurrence of a shoulder dystocia event before any iatrogenic intervention may be associated with brachial plexus injury.

CONCLUSION

For many years, long-standing opinions based solely on empiric reasoning have dictated our understanding of the detailed aspects of shoulder dystocia prevention and management. Despite its infrequent occurrence, all healthcare providers attending pregnancies must be prepared to handle vaginal deliveries complicated by shoulder dystocia.

Shoulder dystocia and injuries: prevention and management

PURPOSE OF REVIEW

Shoulder dystocia is an obstetric emergency that is often unpredictable and unanticipated. Despite the identification of various clinical risk factors, our ability to predict and prevent shoulder dystocia is very limited. Effective and timely clinical management is essential to offer the best chance of a satisfactory outcome.

RECENT FINDINGS

Upon diagnosis of the condition, a team working in tandem to resolve the problem is very effective. Use of the McRoberts maneuver, application of suprapubic pressure, with an adequate episiotomy allow resolution of over 50% of cases, with a low risk of fetal injury. Secondary maneuvers include rotation of the shoulders and delivery of the posterior shoulder. These are technically more challenging and may be associated with a higher risk of fetal injury. More drastic action may be considered in dire cases where even secondary maneuvers fail. These include the Zavanelli maneuver, symphysiotomy or iatrogenic clavicular fracture. These techniques, while seldom required, may be lifesaving in extremely severe cases.

SUMMARY

Upon resolution of the clinical event, it is essential to document the entire event, and to discuss the clinical problem and management with the parents. These actions will reduce the risk of medical litigation, and improve patient satisfaction with clinical care.

Methods of clinical prediction

The ability to predict clinical outcomes is of great importance to physicians and patients alike. Accordingly, multiple different methods have been used in an effort to accurately predict these outcomes. These methods include the development of scoring systems based on univariable and multivariable analysis, as well as models involving the use of neural network, nomograms, and classification and regression trees. The principles of these types of methods, as well as their advantages and disadvantages will be presented.

Shoulder dystocia: prevention and management

Knowledge of the maneuvers used for the alleviation of shoulder dystocia is relevant not only for obstetric residents and attending house staff but also for family practitioners, nurses, and nurse midwives. The performance of shoulder dystocia "drills" can be helpful not only to coordinate a teamwork approach to this obstetric emergency but also to provide an opportunity to practice the maneuvers. Shoulder dystocia continues to represent an immense area of clinical interest because it typically occurs without prediction. All patients in labor should be considered at risk for the development of shoulder dystocia.

Part 1. Injuries to the brachial plexus: mechanisms of injury and identification of risk factors

Upper-arm weakness (paresis) or paralysis indicates peripheral-nerve damage to the brachial plexus, a network of lower cervical and upper thoracic spinal nerves supplying the arm, forearm, and hand. Physical findings reflect muscle paralysis from spinal nerve roots. The mechanism of injury includes maternal, obstetric, and infant factors that apply traction on or compression to the anatomically vulnerable brachial plexus. Nerve regeneration can occur if nerve tissue components are preserved. Recovery is affected by multiple factors, including the type and site of injury, intervention timing, and developmental factors. The majority of injuries recover in days or months; however, residual deficits can persist. Part 1 of 2 of this article provides an overview of the neurophysiology of peripheral-nerve damage and nerve regeneration. The multifactorial etiology of brachial plexus injuries will be reviewed. Photographs and on-line video clips will enhance the description of the brachial plexus injury classifications and illustrate mechanisms of shoulder dystocia and obstetric relief maneuvers. A systematic approach to the physical examination will be explored in Part 2. Serial evaluation of motor function recovery is essential and is accomplished by appropriate referrals and follow-up. Part 2 will also describe treatment options and discuss anticipatory parent guidance.

Cesarean section upon request: is it appropriate for everybody?

The request for cesarean section without medical indication has become one of the dilemmas faced by the obstetrician. Most recent studies that compare vaginal delivery with elective cesarean section find them equally safe. This comparison is lacking in the option of trial of labor, which may result in an assisted vaginal delivery or intrapartum cesarean section, both with increased morbidity and mortality for the mother and newborn. When considering elective cesarean section, the obstetrician has to take into account improved anesthetic techniques and the decrease in morbidity and mortality after cesarean section with the trend toward patient autonomy to decide on her own treatment. On the other hand, the obstetrician has to advise his patient of the best treatment with respect to possible complications in future pregnancies, such as placental complications and increased morbidity and mortality resulting from repeated cesarean sections. The advantage of cesarean section for pelvic floor protection does not exist after three consecutive cesarean sections and equals the rate of urinary incontinence after consecutive three vaginal deliveries. In countries such as ours, where most women wish for several children, the risk-benefit balance is toward repeated spontaneous vaginal deliveries.

Intrapartum Emergencies

Intrapartum emergencies are challenging to all perinatal nurses because of the increased risk of adverse outcomes for the mother and fetus. Perinatal emergencies, such as seizures, amniotic fluid embolus, hemorrhage, and uterine rupture, create physiological challenges and trigger intrinsic survival techniques. The pregnant uterus becomes a vital source of blood volume during hypovolemic events because it is not considered a vital organ. The pregnancy itself may become burdensome, and birth may occur as an intrinsic maternal compensatory mechanism. The resultant fetal hypoxemia may also stress the fetus into initiating labor. During extensive oxygen desaturation and decompensation, the focus should be on maternal stabilization, which will subsequently enhance fetal stabilization. Clinical assessments, critical thinking, decision making, and resource allocation must be quick and appropriate to increase the likelihood of a positive outcome for the mother, fetus, and neonate.