Impact of shoulder dystocia, stratified by type of manoeuvre, on severe neonatal outcome and maternal morbidity

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.

Incidence of shoulder dystocia and risk factors for recurrence in the subsequent pregnancy-A historical register-based cohort study

INTRODUCTION

Shoulder dystocia is a rare obstetric complication, and the risk of recurrence is important for planning future deliveries.

MATERIAL AND METHODS

The objectives of our study were to estimate the incidence and risk factors for recurrence of shoulder dystocia and to identify women at high risk of recurrence in a subsequent vaginal delivery. The study design was a nationwide register-based study including data from the Danish Medical Birth Registry and National Patient Register in the period 2007-2017. Nulliparous women with a singleton fetus in cephalic presentation were included for analysis of risk factors in index and subsequent delivery.

RESULTS

During the study period, 6002 cases of shoulder dystocia were reported with an overall incidence among women with vaginal delivery of 1.2%. Among 222 225 nulliparous women with vaginal births, shoulder dystocia complicated 2209 (1.0%) deliveries. A subsequent birth was registered in 1106 (50.1%) of the women with shoulder dystocia in index delivery of which 837 (77.8%) delivered vaginally. Recurrence of shoulder dystocia was reported in 60 (7.2%) with a six-fold increased risk compared with women without a prior history of shoulder dystocia (risk ratio [RR] 5.70, 95% confidence interval [CI]: 4.41 to 7.38; adjusted RR 3.06, 95% CI: 2.03 to 4.68). Low maternal height was a significant risk factor for recurrence of shoulder dystocia. In the subsequent delivery, significant risk factors for recurrence were birthweight >4000 g, positive fetal weight difference exceeding 250 g from index to subsequent delivery, stimulation with oxytocin and operative vaginal delivery. In the subsequent pregnancy following shoulder dystocia, women who underwent a planned cesarean (n = 176) were characterized by more advanced age and a higher prevalence of diabetes in the subsequent pregnancy. Furthermore, they had more often experienced operative vaginal delivery, severe perineal lacerations, and severe neonatal complications at the index delivery.

CONCLUSIONS

The incidence of shoulder dystocia among nulliparous women with vaginal delivery was 1.0% with a 7.2% risk of recurrence in a population where about 50% had a subsequent birth and of these 78% had subsequent vaginal delivery. Important risk factors for recurrence were low maternal height, increase of birthweight ≥250 g from index to subsequent delivery and operative vaginal delivery.

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.

Neonatal upper limb fractures - a narrative overview of the literature

The aim of this paper is to review the topic of neonatal fractures of the upper limb, describing the different types of fractures focusing on the etiology, epidemiology, risk factors, clinical approach, diagnosis, treatment and prognosis of these injuries. We included all types of research studies, both experimental and observational, published in English, French, Portuguese and Spanish. The information was obtained using the keywords neonatal upper limb fracture, clavicle fracture or humerus fracture from the following resources: MEDLINE database, Embase® database and LILACS database. Other resources such as hand searches of the references of retrieved literature and authoritative texts, personal and hospital libraries searching for texts on upper limb neonatal fractures, discussions with experts in the field of upper limb neonatal fractures and personal experience, were also considered for the completion of the article.Neonatal fractures of the upper limb are consensually considered to have a good prognosis and no long-term sequelae. Conservative treatment is the option in the vast majority of the fractures and is associated with excellent results, with good healing, full range of motion, adequate remodeling without obvious deformity, neurologic impairment or functional implications.

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.

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.

Incidence changes in risk factors associated with the decreasing number of birth-related clavicle fractures in Finland: A nationwide retrospective birth cohort from 2004 to 2017

BACKGROUND

A clavicle fracture is one of the most common birth injuries. The objective of this study was to examine whether the decreased incidence of birth-related clavicle fractures in Finland is because of temporal changes in their predisposing factors.

METHODS

For this nationwide population-based study, we used the Finnish Medical Birth Register and the Care Register for Health Care databases. The study population included all singleton, live-born newborn born spontaneously or by vacuum-assisted delivery, in cephalic presentation ≥37⁺⁰ weeks of gestation. The incidences of clavicle fractures, pregnancy characteristics, and risk assessments for fracture were calculated and compared between two time periods: 2004-2010 and 2011-2017.

RESULTS

A total of 629 457 newborn were born vaginally between 2004 and 2017. The clavicle fracture incidence decreased from 17.6/1000 to 6.2/1000 live births. Shoulder dystocia, diabetes, and birthweight ≥4000 g were the strongest predisposing factors. The incidence of birthweight ≥4000 g decreased, meanwhile type 1 diabetes and shoulder dystocia remained stable and gestational diabetes, type 2 diabetes, and maternal obesity increased in the later study period. The incidence of clavicle fractures without known predisposing factors declined. Simultaneously, the cesarean birth rate remained stable (13.2%-13.1%), although the rate of vacuum-assisted deliveries increased (8.5%-9.5%).

DISCUSSION

The incidence of clavicle fractures decreased, even though the incidence of most risk factors remained stable or increased, and the cesarean birth rate remained stable. This decline may be related to the reduction of fracture incidence among deliveries without known risk factors, and the decrease in birthweight ≥4000 g.

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, umbilical cord blood gases and neonatal encephalopathy

The interpretation of umbilical cord gases may not be straightforward following shoulder dystocia. We reviewed Perinatal and Maternal Mortality Review Committee data from New Zealand infants with moderate and severe neonatal encephalopathy (NE) for 2010-2017 inclusive. If one or more of: pH of ≤7.1; base excess of ≤-12 mmol/L; or lactate of ≥6 mmol/L were present it was considered an abnormal result. One-third (12/36) of infants born following shoulder dystocia had documented umbilical cord gases within the normal range. It is important for clinicians to be aware of this possibility when assessing newborn infants with NE.

Risk factors for neonatal brachial plexus palsy: a systematic review and meta-analysis

AIM

To provide a comprehensive update on the most prevalent, significant risk factors for neonatal brachial plexus palsy (NBPP).

METHOD

Cochrane CENTRAL, MEDLINE, Web of Science, Embase, and ClinicalTrials.gov were searched for relevant publications up to March 2019. Studies assessing risk factors of NBPP in relation to typically developing comparison individuals were included. Meta-analysis was performed for the five most significant risk factors, on the basis of the PRISMA statement and MOOSE guidelines. Pooled odds ratios (ORs), 95% confidence intervals (CIs), and across-study heterogeneity (I² ) were reported. Reporting bias and quality of evidence was rated. In addition, we assessed the incidence of NBPP.

RESULTS

Twenty-two observational studies with a total sample size of 29 419 037 live births were selected. Significant risk factors included shoulder dystocia (OR 115.27; 95% CI 81.35-163.35; I² =92%), macrosomia (OR 9.75; 95% CI 8.29-11.46; I² =70%), (gestational) diabetes (OR 5.33; 95% CI 3.77-7.55; I² =59%), instrumental delivery (OR 3.8; 95% CI 2.77-5.23; I² =77%), and breech delivery (OR 2.49; 95% CI 1.67-3.7; I² =70%). Caesarean section appeared as a protective factor (OR 0.13; 95% CI 0.11-0.16; I² =41%). The pooled overall incidence of NBPP was 1.74 per 1000 live births. It has decreased in recent years.

INTERPRETATION

The incidence of NBPP is decreasing. Shoulder dystocia, macrosomia, maternal diabetes, instrumental delivery, and breech delivery are risk factors for NBPP. Caesarean section appears as a protective factor.

WHAT THIS PAPER ADDS

The overall incidence of neonatal brachial plexus palsy is 1.74 per 1000 live births. The incidence has declined significantly. Shoulder dystocia, macrosomia, maternal diabetes, instrumental delivery, and breech delivery are the main risk factors. Prevention is difficult owing to unpredictability and often labour-related risk.