Complications of shoulder dystocia

Shoulder dystocia in babies born to Aboriginal mothers with diabetes: a population-based cohort study, 1998-2015

BACKGROUND

Australian Aboriginal and Torres Strait Islander women with diabetes in pregnancy (DIP) are more likely to have glycaemic levels above the target range, and their babies are thus at higher risk of excessive fetal growth. Shoulder dystocia, defined by failure of spontaneous birth of fetal shoulder after birth of the head requiring obstetric maneuvers, is an obstetric emergency that is strongly associated with DIP and fetal size. The aim of this study was to investigate the epidemiology of shoulder dystocia in Aboriginal babies born to mothers with DIP.

METHODS

Stratifying by Aboriginal status, characteristics of births complicated by shoulder dystocia in women with and without DIP were compared and incidence and time-trends of shoulder dystocia were described. Compliance with guidelines aiming at preventing shoulder dystocia in women with DIP were compared. Post-logistic regression estimation was used to calculate the population attributable fractions (PAFs) for shoulder dystocia associated with DIP and to estimate probabilities of shoulder dystocia in babies born to mothers with DIP at birthweights > 3 kg.

RESULTS

Rates of shoulder dystocia from vaginal births in Aboriginal babies born to mothers with DIP were double that of their non-Aboriginal counterparts (6.3% vs 3.2%, p < 0.001), with no improvement over time. Aboriginal mothers with diabetes whose pregnancies were complicated by shoulder dystocia were more likely to have a history of shoulder dystocia (13.1% vs 6.3%, p = 0.032). Rates of guideline-recommended elective caesarean section in pregnancies with diabetes and birthweight > 4.5 kg were lower in the Aboriginal women (28.6% vs 43.1%, p = 0.004). PAFs indicated that 13.4% (95% CI: 9.7%-16.9%) of shoulder dystocia cases in Aboriginal (2.7% (95% CI: 2.1%-3.4%) in non-Aboriginal) women were attributable to DIP. Probability of shoulder dystocia among babies born to Aboriginal mothers with DIP was higher at birthweights > 3 kg.

CONCLUSIONS

Aboriginal mothers with DIP had a higher risk of shoulder dystocia and a stronger association between birthweight and shoulder dystocia. Many cases were recurrent. These factors should be considered in clinical practice and when counselling women.

Pitfalls in the diagnostics of shoulder dystocia: an analysis based on the scrutiny of 2274 deliveries

PURPOSE

Shoulder dystocia is an obstetric emergency with severe complications. Our objective was to evaluate the major pitfalls in the diagnostics of shoulder dystocia, diagnostic descriptions documented in medical records, use of obstetric maneuvers, and their correlations to Erb's and Klumpke's palsy and the use of ICD-10 code 066.0.

METHODS

A retrospective, register-based case-control study included all deliveries (n = 181 352) in Hospital District of Helsinki and Uusimaa (HUS) area in 2006-2015. Potential shoulder dystocia cases (n = 1708) were identified from the Finnish Medical Birth Register and the Hospital Discharge Register using ICD-10 codes O66.0, P13.4, P14.0, and P14.1. After thorough assessment of all medical records, 537 shoulder dystocia cases were confirmed. Control group consisted of 566 women without any of these ICD-10 codes.

RESULTS

The pitfalls in the diagnostic included suboptimal following of guidelines for making the diagnosis of shoulder dystocia, subjective interpretation of diagnostic criteria, and inexact or inadequate documentation in medical records. The diagnostic descriptions in medical record were highly inconsistent. The use of obstetric maneuvers was suboptimal among shoulder dystocia cases (57.5%). Overall, the use of obstetric maneuvers increased during the study period (from 25.7 to 97.0%, p < 0.001), which was associated with decreasing rate of Erb's palsy and increasing use of ICD-10 code O66.0.

CONCLUSION

There are diagnostic pitfalls, which could be addressed by education regarding shoulder dystocia guidelines, by improved use obstetric maneuvers, and more precise documentation. The increased use of obstetric maneuvers was associated with lower rates of Erb's palsy and improved coding of shoulder dystocia.

A critical evaluation of the external and internal maneuvers for resolution of shoulder dystocia

In the management of shoulder dystocia, it is often recommended to start with external maneuvers, such as the McRoberts maneuver and suprapubic pressure, followed by internal maneuvers including rotation and posterior arm delivery. However, this sequence is not based on scientific evidence of its success rates, the technical simplicity, or the related complication rates. Hence, this review critically evaluates the success rate, technique, and safety of different maneuvers. Retrospective reviews showed that posterior arm delivery has consistently higher success rates (86.1%) than rotational methods (62.4%) and external maneuvers (56.0%). McRoberts maneuver was thought to be a simple method, however, its mechanism is not clear. Furthermore, McRoberts position still requires subsequent traction on the fetal neck, which presents a risk for brachial plexus injury. The 2 internal maneuvers have anatomic rationales with the aim of rotating the shoulders to the wider oblique pelvic dimension or reducing the shoulder width. The techniques are not more sophisticated and requires the accoucher to insert the correct hand (according to fetal face direction) through the more spacious sacro-posterior region and deep enough to reach the fetal chest or posterior forearm. The performance of rotation and posterior arm delivery can also be integrated and performed using the same hand. Retrospective studies may give a biased view that the internal maneuvers are riskier. First, a less severely impacted shoulder dystocia is more likely to have been managed by external maneuvers, subjecting more difficult cases to internal maneuvers. Second, neonatal injuries were not necessarily caused by the internal maneuvers that led to delivery but could have been caused by the preceding unsuccessful external maneuvers. The procedural safety is not primarily related to the nature of the maneuvers, but to how properly these maneuvers are performed. When all these maneuvers have failed, it is important to consider the reasons for failure otherwise repetition of the maneuver cycle is just a random trial and error. If the posterior axilla is just above the pelvic outlet and reachable, posterior axilla traction using either the accoucher fingers or a sling is a feasible alternative. Its mechanism is not just outward traction but also rotation of the shoulders to the wider oblique pelvic dimension. If the posterior axilla is at a higher sacral level, a sling may be formed with the assistance of a long right-angle forceps, otherwise, more invasive methods such as Zavanelli maneuver, abdominal rescue, or symphysiotomy are the last resorts.

Maternal and neonatal complications of shoulder dystocia with a focus on obstetric maneuvers: A case-control study of 1103 deliveries

INTRODUCTION

Shoulder dystocia is a severe obstetric emergency that can cause substantial neonatal and maternal complications. This study aims to assess the performed obstetric maneuvers and their frequency, success, and association with maternal and neonatal complication rates.

MATERIAL AND METHODS

The study population was collected among all deliveries in the Hospital District of Helsinki and Uusimaa between 2006 and 2015 (n = 181 352) by searching for ICD-10 codes for shoulder dystocia, brachial plexus injury and clavicle fracture. Shoulder dystocia cases (n = 537) were identified by reviewing the medical records. Shoulder dystocia cases treated with one or two maneuvers were compared with those treated with at least three. Medical records of a matched control group constituting of 566 parturients without any of the forementioned ICD-10 codes were also scrutinized.

RESULTS

Using the four most common obstetric maneuvers (McRoberts maneuver, suprapubic pressure, rotational maneuvers, the delivery of the posterior arm) significantly increased during the study period with individual success rates of 61.0%, 71.9%, 68.1% and 84.8%, respectively. Concurrently, the rate of brachial plexus injury and combined neonatal morbidity significantly declined from 50% to 24.2% (p = 0.02) and from 91.4% to 48.5% (p < 0.001). Approximately 75% of shoulder dystocia cases treated with maneuvers were resolved by the McRoberts maneuver and/or suprapubic pressure, but each of the four most performed maneuvers significantly increased the cumulative success rate individually and statistically (p < 0.001). The rates of brachial plexus injury and combined neonatal morbidity were at their highest (52.9% and 97.8%) when none of the maneuvers were performed and at their lowest when two maneuvers were performed (43.0% and 65.4%). The increasing number (≥3) of maneuvers did not affect the combined maternal or neonatal morbidity or brachial plexus injury but increased the risk for third- or fourth-degree lacerations (odds ratio 2.91, 95% confidence interval 1.17 to 7.24).

CONCLUSIONS

The increased use of obstetric maneuvers during the study period was associated with decreasing rates of neonatal complications; conversely, the lack of obstetric maneuvers was associated with the highest rate of neonatal complications. These emphasize the importance of education, maneuver training and urgently performing shoulder dystocia maneuvers according to the international protocol guidelines.

The impact of diabetes during pregnancy on neonatal outcomes among the Aboriginal population in Western Australia: a whole-population study

BACKGROUND

Aboriginal and Torres Strait Islander (hereafter Aboriginal) women have a high prevalence of diabetes in pregnancy (DIP), which includes pre-gestational diabetes mellitus (PGDM) and gestational diabetes mellitus (GDM). We aimed to characterize the impact of DIP in babies born to Aboriginal mothers.

METHODS

A retrospective cohort study, using routinely collected linked health data that included all singleton births (N = 510 761) in Western Australia between 1998 and 2015. Stratified by Aboriginal status, generalized linear mixed models quantified the impact of DIP on neonatal outcomes, estimating relative risks (RRs) with 95% CIs. Ratio of RRs (RRRs) examined whether RRs differed between Aboriginal and non-Aboriginal populations.

RESULTS

Exposure to DIP increased the risk of adverse outcomes to a greater extent in Aboriginal babies. PGDM heightened the risk of large for gestational age (LGA) (RR: 4.10, 95% CI: 3.56-4.72; RRR: 1.25, 95% CI: 1.09-1.43), macrosomia (RR: 2.03, 95% CI: 1.67-2.48; RRR: 1.39, 95% CI: 1.14-1.69), shoulder dystocia (RR: 4.51, 95% CI: 3.14-6.49; RRR: 2.19, 95% CI: 1.44-3.33) and major congenital anomalies (RR: 2.14, 95% CI: 1.68-2.74; RRR: 1.62, 95% CI: 1.24-2.10). GDM increased the risk of LGA (RR: 2.63, 95% CI: 2.36-2.94; RRR: 2.00, 95% CI: 1.80-2.22), macrosomia (RR: 1.95, 95% CI: 1.72-2.21; RRR: 2.27, 95% CI: 2.01-2.56) and shoulder dystocia (RR: 2.78, 95% CI: 2.12-3.63; RRR: 2.11, 95% CI: 1.61-2.77). Birthweight mediated about half of the DIP effect on shoulder dystocia only in the Aboriginal babies.

CONCLUSIONS

DIP differentially increased the risks of fetal overgrowth, shoulder dystocia and congenital anomalies in Aboriginal babies. Improving care for Aboriginal women with diabetes and further research on preventing shoulder dystocia among these women can reduce the disparities.

Impact of fetal manipulation on maternal and neonatal severe morbidity during shoulder dystocia management

PURPOSE

There are few data on maternal and neonatal morbidities associated with shoulder dystocia (SD), depending on the use of fetal manipulation (FM). A prior 5-year study was conducted in our center in 2012 for this purpose. Our objective was to compare severe maternal and neonatal morbidities according to FM execution in a larger cohort.

METHODS

We conducted a retrospective study between 2007 and 2020. SD was considered when additional maneuvers were required to complete a delivery. Severe maternal morbidity was defined as the occurrence of obstetric anal sphincter injury (OASI). Severe neonatal morbidity was defined as Apgar < 7 at 5 min and/or cord arterial pH < 7.1 and/or or a permanent brachial plexus palsy. We studied these data in the FM group compared to the non- FM group.

RESULTS

FM was associated with increased OASI rates (21.1% vs. 3.8%, OR = 6.72 [2.7-15.8]). We found no significant difference in severe neonatal morbidity. Maternal age > 35 and FM appear to be associated with the occurrence of OASI, with ORa = 13.3 [1.5-121.8] and ORa = 5.3 [2.2-12.8], respectively. FM was the only factor associated with the occurrence of severe neonatal morbidity (ORa = 2.3 [1.1-4.8]. The rate of episiotomy was significantly decreased (20% versus 5% p < 0.05) and there was an increase in the rate of SD managed with FM in our center.

CONCLUSION

FM is the only factor associated with an increased risk of OASI. In case of failure of non-FM maneuvers, the rapid implementation of FM maneuvers resulted in no difference regarding severe neonatal morbidity.

Comorbidities in Infants and Children with Neonatal Brachial Plexus Palsy: A Scoping Review to Inform Multisystem Screening

AIMS

The scoping review was undertaken to explore comorbidities in infants and children with neonatal brachial plexus palsy (NBPP). The purpose of the review was to inform physical and occupational therapy screening of multiple body systems during the examination of children with NBPP.

METHODS

EBSCO Discovery and EMBASE electronic databases were searched for reports published between January 1996 and September 2021 describing comorbidities in children with NBPP between birth and 18 years. Key data pertaining to comorbidity prevalence, risk factors, clinical features, and associated outcomes were extracted and charted by one researcher and confirmed by a second researcher.

RESULTS

Thirty-six articles were included in the scoping review. Fourteen comorbidities were identified across the musculoskeletal, neurological, cardiopulmonary, and integumentary systems and the communication domain. The most prevalent comorbidities were clavicle fractures, plagiocephaly, torticollis, high body mass index, and language delays. The least prevalent comorbidity was facial nerve palsy.

CONCLUSIONS

Physical and occupational therapists can use knowledge of comorbidities in infants and children with NBPP for multisystem screening during the examination. A thorough history can identify risk factors for comorbidities. Detection of comorbidities during screening allows for timely specialty referrals to optimize care.

Clavicle length and shoulder breadth in hominoid evolution

For a given body mass, hominoids have longer clavicles than typical monkeys, reflecting the lateral reorientation of the hominoid glenoid. Relative length of the clavicle varies among hominoids, with orangutans having longer clavicles than expected for body mass and gorillas and chimpanzees having shorter clavicles than expected. Modern humans conform to the general hominoid distribution, but Neandertals and Upper Paleolithic Homo sapiens have longer clavicles than expected for their size and exhibit marked positive allometry in clavicle length. Relative to clavicle length, adult and newborn humans have broader shoulders (biacromial breadths) than comparable apes, because the reduced elevation of the human shoulder swings the acromion laterally downward away from the head. Since broadened shoulders yield an increased risk of maternal and neonatal injury and/or death from shoulder dystocia during birth, we might expect hominins to manifest trends toward reduction in shoulder breadth and clavicle length. They do not, presumably because of countering selection pressures favoring a long clavicle in the adults. The marked sexual dimorphism seen in patterns of clavicular growth and static adult allometry in humans suggests that those selection pressures have disproportionately affected the males.

Human shoulder development is adapted to obstetrical constraints

SignificanceDuring human birth, the risk of complications is relatively high because of the comparatively large dimensions of the fetal head and shoulders relative to the maternal birth canal. Here we show that humans exhibit a developmental mode of the shoulders that likely contributes to mitigating obstetrical problems. Human shoulder growth is decelerated before birth but accelerated after birth, which stands in contrast to the more uniform shoulder growth trajectories of chimpanzees and macaques. This indicates that fetal developmental modifications were required during human evolution not only in the head but also in the shoulders to compensate obstetrical constraints.

Newborn Clavicle Fractures: Does Clavicle Fracture Morphology Affect Brachial Plexus Injury?

BACKGROUND

Newborn clavicle fractures and brachial plexus injuries (BPIs) are rare but serious perinatal complications.

METHODS

The aim of this study was to examine the clinical relationship between the fracture morphology (spiral, oblique, transfer) of clavicle fractures that develop during delivery in newborns and BPI. We retrospectively reviewed all perinatal clavicle fractures diagnosed at our institution over 6 years.

RESULTS

The study included 55 newborn infants with perinatal clavicle fracture. Of these, 60% (n=33) were male. Right-side clavicle fractures were present in 56.4% (n=31) and shoulder dystocia was present in 58.2% (n=32) of the patients. Of the fracture localization of the patients, 85.5% (n=47) (Allman I) and 14.5% (n=8) (Allman II) were lateral. Allman type I fractures were not associated with increased BPI (P>0.05). It was observed that 40% (n=22) of the clavicle fractures were characterized by oblique morphology, 34.5% (n=19) of the fractures by spiral morphology, and 25.5% (n=14) of the fractures by transfer morphology. In all, 41.8% (n=23) of the sample also had BPI. Of the entire sample, 40% (n=22) most frequently showed oblique morphology fractures, whereas the patient group with BPI showed spiral morphology as the most common fracture, at a rate of 52.2% (n=10). After examining the relationship between fracture morphology and BPI, the study determined a statistically significant correlation between spiral and oblique morphology fractures and the development of BPI.

CONCLUSIONS

To our knowledge, our study is the first to examine the relationship between newborn clavicle fracture morphology and BPI. We think that they should be evaluated for increased BPI risk in newborn patients that have clavicle fractures with spiral and oblique morphology.

Overview of techniques to manage shoulder dystocia during vaginal birth

Shoulder dystocia is an obstetric emergency which is unpredictable and complicates approximately 0.5-1% of vaginal births. This article discusses the risk factors and the associated fetal and maternal complications, while it is also an overview of techniques and algorithms to handle shoulder dystocia.

Rising trends in the incidence of shoulder dystocia and development of a novel shoulder dystocia risk score tool: a nationwide population-based study of 800 484 Finnish deliveries

INTRODUCTION

Shoulder dystocia has remained an unpredictable and feared emergency in obstetrics. Some risk factors have been identified but nevertheless there is a lack of risk evaluation tools in clinical practice. The aim of this study was to evaluate the incidence and risk factors of shoulder dystocia in the Finnish population and to develop a shoulder dystocia risk score tool.

MATERIAL AND METHODS

This retrospective, population-based study included all deliveries in Finland between 2004 and 2017 (n = 800 484). The annual numbers of shoulder dystocia diagnoses were gathered from nationwide Finnish Medical Birth Register and Hospital Discharge Register. The incidence of shoulder dystocia was calculated in subgroups according to the mode of delivery, maternal diabetes status, body mass index (BMI), age, parity and gestational age. Based on these numbers, a shoulder dystocia risk score tool was created.

RESULTS

The overall incidence of shoulder dystocia was 0.18%. It increased significantly during the study period from 0.10% to 0.32% (P < .001). More specifically, the incidence increased significantly in all analyzed subgroups except for women with BMI <18.5 or age <20 years. To evaluate the importance of risk factors, practical and simple shoulder dystocia risk score tool was created. Instrumental vaginal delivery, maternal diabetes of any kind, BMI ≥25, age ≥40 years and gestational age ≥41 weeks were associated with higher shoulder dystocia risk compared with non-diabetic, non-obese and younger women with spontaneous deliveries before 41 weeks of gestation. In our risk score tool, cases with shoulder dystocia had a significantly higher number of risk points than those without it (15.2 vs 10.4, P < .001). The risk was significantly high when the scores were ≥18 points (relative risk 9.54, 95% confidence interval 8.61-10.57).

CONCLUSIONS

The incidence of shoulder dystocia in Finland increased during the study period but it is still low compared with previous studies from other countries. In clinical daily practice, the new shoulder dystocia risk score tool helps to evaluate the individual risk profile of the parturient. According to this risk score tool, the highest risk was found with the combination of instrumental vaginal delivery, maternal diabetes, BMI ≥25, age ≥40 years and gestational age ≥41 weeks.

Trends of changes in the specific contribution of selected risk factors for shoulder dystocia over a period of more than two decades

Objectives Shoulder dystocia (SD) is an obstetrical emergency with well-recognized risk factors. We aimed to identify trends of changes in the specific contribution of risk factors for SD over time. Methods A nested case control study comparing all singleton deliveries with and without SD was undertaken. A multivariable logistic regression model was used in order to identify independent risk factors for SD and a comparison of the prevalence and the specific contribution (odds ratio (OR)) of the chosen risk factors in three consecutive eight-year intervals from 1988 to 2014 was performed. Results During the study period, there were 295,946 deliveries. Of them 514 (0.174%) were complicated with SD. Between 1988 and 2014 the incidence of SD has decreased from 0.3% in 1988 to 0.1% in 2014. Using a logistic regression model grandmultiparity, diabetes mellitus (DM), fetal weight, and large for gestational age (LGA) were found to be independent risk factors for SD (OR 1.25 95% CI 1.04-1.51, p=0.02; OR 1.53 95% CI 1.19-1.97, p=0.001; OR 1.002 95% CI 1.001-1.002, p < 0.001; OR 3.88 95% CI 3.09-4.87, p < 0.001; respectively). While the OR for grandmultiparity, fetal weight, and LGA has significantly changed during the study period with a mixed trend, the OR of DM has demonstrated a significant linear increase over time. Conclusions The individual contribution of selected risk factors for the occurrence of SD has significantly changed throughout the years. The contribution of DM has demonstrated a linear increase over time, emphasizing the great impact of DM on SD.

Intrapartum Asphyxiated Newborns Without Fetal Heart Rate and Cord Blood Gases Abnormalities: Two Case Reports of Shoulder Dystocia to Reflect Upon

Our report covers two cases of severe hypoxic-ischemic encephalopathy in newborns whose birth was complicated by shoulder dystocia. In both cases, there were inconsistencies observed among cardiotocographic traces, baby's clinical conditions at birth, and umbilical cord blood gases. Namely, normal cardiotocographic monitoring and cord pH > 7, in spite of the fact that the newborns were severely depressed at birth and their blood gases evaluated within 1 h from birth showed a severe metabolic acidosis. Moreover, one of the two newborns displayed moderately low hemoglobin levels. Metabolic and infectious causes were ruled out. Both newborns developed severe hypoxic-ischemic encephalopathy and received therapeutic hypothermia for 72 h. Both survived, one with a severe dystonic cerebral palsy whereas the other developed only a mild developmental delay in language. Cardiac asystole theory could explain these two cases, reinforcing the need for specific resuscitation guidelines for infants experiencing a birth complicated by shoulder dystocia.

Delivery room emergencies due to birth injuries

Delivery room emergencies due to birth injuries are serious, usually unexpected, and can be distressing situations that necessitate immediate action to reduce neonatal morbidity and prevent neonatal mortality. Birth injuries requiring immediate, urgent care in the delivery room are uncommon, hence knowledge of obstetric risk factors and prenatal conditions linked to birth injury is an important first step in the management of affected neonates. Furthermore, immediate recognition of injury and quick action upon delivery is essential in order to achieve the best possible outcomes. This chapter briefly reviews the known risk factors associated with birth injury, and then discusses the identification and management of specific injuries that may require immediate treatment in the delivery room, or hasty management within hours after birth.

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.

A Study of the Diagnostic Accuracy of an Existing Multivariable Test to Predict Shoulder Dystocia

Objectives  To evaluate the diagnostic accuracy of a multivariable prediction model, the Shoulder Screen (Perigen, Inc.), and compare it with the American College of Obstetricians and Gynecologists (ACOG) guidelines to prevent harm from shoulder dystocia. Study Design  The model was applied to two groups of 199 patients each who delivered during a 4-year period. One group experienced shoulder dystocia and the other group delivered without shoulder dystocia. The model's accuracy was analyzed. The performance of the model was compared with the ACOG guideline. Results  The sensitivity, specificity, positive, and negative predictive values of the model were 23.1, 99.5, 97.9, and 56.4%, respectively. The sensitivity of the ACOG guideline was 10.1%. The false-positive rate of the model was 0.5%. The accuracy of the model was 61.3%. Conclusion  A multivariable prediction model can predict shoulder dystocia and is more accurate than ACOG guidelines.

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.

Anal sphincter injury associated with shoulder dystocia

Objective: Shoulder dystocia is an obstetric emergency, occurring in 0.2-3% of vaginal deliveries. Research has mainly focused on the neonatal morbidity arising from shoulder dystocia, such as brachial plexus injury and hypoxic-ischemic encephalopathy. Maternal morbidity is thought to be increased with shoulder dystocia though is much less commonly reported. Obstetric anal sphincter injury remains the leading cause of fecal incontinence in women and shares several antenatal and intrapartum risk factors with shoulder dystocia. The aim of this study was to identify risk factors for sphincter injury associated with shoulder dystocia.Methods: This retrospective analysis included all cases of shoulder dystocia from 2008 to 2017 in a single unit in North-East Ireland. Maternal characteristics and delivery outcomes were analyzed. Two groups were compared, those with and without anal sphincter injury in our shoulder dystocia cohort and those with and without shoulder dystocia, regardless of sphincter injury. Univariate and multivariate logistic regression models were used to examine risk factors for sphincter injury.Results: There were 24,159 singleton cephalic vaginal deliveries over the study period, with 495 cases of shoulder dystocia, giving an incidence of 2.1% (495/24 159). The rate of anal sphincter injury in those with shoulder dystocia was 4.4% (22/495), with 7.6% (12/158) in nulliparas, and 3.0% (10/337) among multiparas. Women with sphincter damage were more likely to be nulliparous than those with an intact sphincter (54.5% [12/22] vs. 30.9% [146/473]; p = .036) and have an operative vaginal delivery (72.7% [16/22] vs. 39.1% [185/473]; p = .004). Episiotomy was more common in those with a sphincter injury (68.2% [15/22] vs. 37.0% [175/473]; p = .007). On univariate regression analysis, nulliparity (OR 2.69) and operative vaginal delivery (OR 4.15) were associated with sphincter injury. No risk factors were identified on multivariate regression analysis.Discussion: In our population, the risk of anal sphincter injury with shoulder dystocia is 4.4%. Risk factors include nulliparity and operative vaginal delivery. After controlling for other factors, these associations became nonsignificant. Further research into sphincter injury at shoulder dystocia is warranted.

Introduction of Posterior Axilla Sling Traction in Simulated Shoulder Dystocia

Objective  Aim of this study was to introduce posterior axilla sling traction (PAST) in delivering providers and nursing staff as an adjunct to the management of shoulder dystocia and evaluate comfort in performing the maneuver. Methods  A presimulation questionnaire had given to all participants. A brief training on how to perform PAST was also given. A simulated shoulder dystocia was run where usual maneuvers failed. Participants used PAST for delivery of posterior shoulder, delivery of posterior arm, and to assist with rotation. Participants were then given a post-simulation questionnaire. A Chi-squared test was used to evaluate comfort with performing the procedure pre and post-simulation. Results  Data were collected from 43 participants at pre and post-simulation. Designations (attending, resident, midwife, registered nurse) and responses were recorded to the questionnaires. There was a statistically significant increase in the number of providers and nurses who would feel comfortable using PAST for shoulder dystocia management and for rotational maneuvers. Ninety-three percent of participants would consider using PAST in future shoulder dystocia when usual maneuvers failed. Conclusion  PAST is an adjunct to management of shoulder dystocia that has not previously been taught in our facility. The majority of participants in our simulation felt comfortable with using PAST.

Lactobacilli Dominance and Vaginal pH: Why Is the Human Vaginal Microbiome Unique?

The human vaginal microbiome is dominated by bacteria from the genus Lactobacillus, which create an acidic environment thought to protect women against sexually transmitted pathogens and opportunistic infections. Strikingly, lactobacilli dominance appears to be unique to humans; while the relative abundance of lactobacilli in the human vagina is typically >70%, in other mammals lactobacilli rarely comprise more than 1% of vaginal microbiota. Several hypotheses have been proposed to explain humans' unique vaginal microbiota, including humans' distinct reproductive physiology, high risk of STDs, and high risk of microbial complications linked to pregnancy and birth. Here, we test these hypotheses using comparative data on vaginal pH and the relative abundance of lactobacilli in 26 mammalian species and 50 studies (N = 21 mammals for pH and 14 mammals for lactobacilli relative abundance). We found that non-human mammals, like humans, exhibit the lowest vaginal pH during the period of highest estrogen. However, the vaginal pH of non-human mammals is never as low as is typical for humans (median vaginal pH in humans = 4.5; range of pH across all 21 non-human mammals = 5.4-7.8). Contrary to disease and obstetric risk hypotheses, we found no significant relationship between vaginal pH or lactobacilli relative abundance and multiple metrics of STD or birth injury risk (P-values ranged from 0.13 to 0.99). Given the lack of evidence for these hypotheses, we discuss two alternative explanations: the common function hypothesis and a novel hypothesis related to the diet of agricultural humans. Specifically, with regard to diet we propose that high levels of starch in human diets have led to increased levels of glycogen in the vaginal tract, which, in turn, promotes the proliferation of lactobacilli. If true, human diet may have paved the way for a novel, protective microbiome in human vaginal tracts. Overall, our results highlight the need for continuing research on non-human vaginal microbial communities and the importance of investigating both the physiological mechanisms and the broad evolutionary processes underlying human lactobacilli dominance.

A multistate population-based analysis of linked maternal and neonatal discharge records to identify risk factors for neonatal brachial plexus injury

OBJECTIVE

To evaluate the interaction and contribution of maternal and fetal risk factors associated with neonatal brachial plexus injury (BPI).

METHODS

In a case-control study, matched maternal and neonatal discharge records were accessed from US State Inpatient Databases for New Jersey (2010-2012), Michigan (2010-2011), and Hawaii (2010-2011). Univariate and multivariate logistic regressions were used to evaluate associations between risk factors and BPI. Area under the receiver operating characteristic curve was used to build predictive models, including two stratified models evaluating deliveries among obese and diabetic cohorts.

RESULTS

Among 376 325 deliveries, BPI was diagnosed in 274 (0.1%). Significant BPI risk factors included maternal obesity (odds ratio [OR] 2.7, 95% confidence interval [CI] 1.7-4.4), maternal diabetes (OR 4.6, 95% CI 3.0-7.0), use of forceps (OR 4.6, 95% CI 2.3-9.0), and vacuum assistance (OR 2.3, 95% CI 1.7-3.3). After adjusting for shoulder dystocia and other predictive factors, cesarean reduced the risk of BPI by 88% (OR 0.1, 95% CI 0.07-0.2). When stratified by obesity and diabetes, the ORs for BPI increased significantly for macrosomia, forceps, and vacuum assistance.

CONCLUSION

The analysis confirms and quantifies more precisely the impact of risk factors for neonatal BPI, and provides a reliable basis for evidence-based clinical decision-making models.

Intrauterine fetal death and risk of shoulder dystocia at delivery

INTRODUCTION

Vaginal delivery is recommended after intrauterine fetal death. However, little is known about the risk of shoulder dystocia in these deliveries. We studied whether intrauterine fetal death increases the risk of shoulder dystocia at delivery.

MATERIAL AND METHODS

In this population-based register study using the Medical Birth Registry of Norway, we included all singleton pregnancies with vaginal delivery of offspring in cephalic presentation in Norway during the period 1967-2012 (n = 2 266 118). Risk of shoulder dystocia was estimated as absolute risk (%) and odds ratio with 95% confidence interval. Adjustment was made for offspring birthweight (in grams). We performed sub-analyses within categories of birthweight (<4000 and ≥4000 g) and in pregnancies with maternal diabetes.

RESULTS

Shoulder dystocia occurred in 1.1% of pregnancies with intrauterine fetal death and in 0.8% of pregnancies without intrauterine fetal death (p < 0.0001) (crude odds ratio 1.5, 95% confidence interval 1.2-4.9). After adjustment for birthweight, the odds ratio was 5.9 (95% confidence interval 4.7-7.4). In pregnancies with birthweight ≥4000 g, shoulder dystocia occurred in 14.6% of pregnancies with intrauterine fetal death and in 2.8% of pregnancies without intrauterine fetal death (p < 0.001) (crude odds ratio 5.9, 95% confidence interval 4.5-7.9). In pregnancies with birthweight ≥4000 g and concurrent maternal diabetes, shoulder dystocia occurred in 57.1% of pregnancies with intrauterine fetal death and 9.6% of pregnancies without intrauterine fetal death (p < 0.001) (crude odds ratio 12.6, 95% confidence interval 5.9-26.9).

CONCLUSIONS

Intrauterine fetal death increased the risk of shoulder dystocia at delivery, and the absolute risk of shoulder dystocia was particularly high if offspring birthweight was high and the mother had diabetes.

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.

Shoulder dystocia: prediction and management

Shoulder dystocia is a complication of vaginal delivery and the primary factor associated with brachial plexus injury. In this review, we discuss the risk factors for shoulder dystocia and propose a framework for the prediction and prevention of the complication. A recommended approach to management when shoulder dystocia occurs is outlined, with review of the maneuvers used to relieve the obstruction with minimal risk of fetal and maternal injury.

Shoulder dystocia in primary midwifery care in the Netherlands

INTRODUCTION

In the Netherlands, low-risk pregnancies are managed by midwives in primary care. Despite strict definitions of low risk, obstetric complications can occur. Midwives seldom encounter uncommon labour complications, but are sufficiently trained to manage these. We assessed neonatal and maternal outcome after management of shoulder dystocia in primary midwifery care.

MATERIALS AND METHODS

In this 2-year prospective cohort study from April 2008 to April 2010, primary-care midwives, who participated in an obstetric emergency course, reported all obstetric complications. Main outcome was neonatal and maternal outcome.

RESULTS

In sixty-four cases of shoulder dystocia McRoberts was the first maneuver in 42/64 (65.6%) cases with a success rate of 23.8%. All-fours maneuver was most frequently used as the second maneuver (24/45; 53.3%). No neonatal mortality occurred, none of the infants suffered from hypoxic ischemic injury, two (3.1%) had transient brachial plexus injuries, two (3.1%) had fractured clavicles and one (1.6%) had a fractured humerus. Eight (12.5%) neonates were successfully resuscitated because of birth asphyxia. All infants fully recovered. In neonates with immediate adverse outcome significantly more maneuvers were used compared with those without adverse neonatal outcome (p = 0.02). Postpartum hemorrhage occurred in 2/64 (3.1%) women, deep vaginal lacerations in 2/64 (3.1%), perineal tears in 23/64 (35.9%). No anal sphincter injuries occurred.

CONCLUSIONS

McRoberts and all-fours maneuvers are widely used by primary-care midwives in the management of shoulder dystocia. Low rates of adverse neonatal and maternal outcomes were observed in cases of shoulder dystocia up to 6 weeks postpartum.

[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.

[Assessment of shoulder dystocia related knowledge among French obstetrics and gynecology residents]

OBJECTIVE

To study the related knowledge of French residents in obstetrics concerning maneuvers for shoulder dystocia (SD).

MATERIALS AND METHODS

Multicenter descriptive transversal study conducted from June to September 2014. Data collection was performed through questionnaires sent by email to French resident in obstetrics.

RESULTS

Among the 1080 questionnaires sent, 366 responses were obtained with a response rate of 33.9%. One hundred and forty-three residents (39.1%) were in the first part of their training (≤5th semester) and 60.9% (n=223) were in the second part of their training. Theoretical training on the SD was provided to 88.2% of resident (n=323). In total, 38.8% (n=142) obtained their French degree in mechanical and technical obstetric and among them 77.5% (n=110) had the opportunity to train on simulators and dummies. Concerning their practical experiences, 31.5% (n=45) residents ≤5th semester reported having experienced SD during their residency vs 58.3% (n=130) amongst oldest residents (P<0.001). In the second part of residency, 40% of residents (n=89) expressed to feel able to manage shoulder dystocia. Only 19.1% (n=70) were satisfied with their residency training program vs 39.1% (n=143) who were unsatisfied.

CONCLUSION

Our study showed that less than one resident out of two (40%) felt able to perform maneuvers for SD in the second part of residency. We think that simulation activities should be mandatory for residency training programs in Obstetrics and Gynecology, which have to develop dependable measures to assess resident competencies to execute practical maneuvers for clinical emergencies in obstetrics.

Primate pelvic anatomy and implications for birth

The pelvis performs two major functions for terrestrial mammals. It provides somewhat rigid support for muscles engaged in locomotion and, for females, it serves as the birth canal. The result for many species, and especially for encephalized primates, is an 'obstetric dilemma' whereby the neonate often has to negotiate a tight squeeze in order to be born. On top of what was probably a baseline of challenging birth, locomotor changes in the evolution of bipedalism in the human lineage resulted in an even more complex birth process. Negotiation of the bipedal pelvis requires a series of rotations, the end of which has the infant emerging from the birth canal facing the opposite direction from the mother. This pattern, strikingly different from what is typically seen in monkeys and apes, places a premium on having assistance at delivery. Recently reported observations of births in monkeys and apes are used to compare the process in human and non-human primates, highlighting similarities and differences. These include presentation (face, occiput anterior or posterior), internal and external rotation, use of the hands by mothers and infants, reliance on assistance, and the developmental state of the neonate.