Shoulder Dystocia: Etiology, Common Risk Factors, and Management

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.

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.

Gestational Weight Gain: Results from the Delta Healthy Sprouts Comparative Impact Trial

Introduction. Delta Healthy Sprouts trial was designed to test the comparative impact of two home visiting programs on weight status, dietary intake, and health behaviors of Southern African American women and their infants. Results pertaining to the primary outcome, gestational weight gain, are reported. Methods. Participants (n = 82), enrolled early in their second trimester of pregnancy, were randomly assigned to one of two treatment arms. Gestational weight gain, measured at six monthly home visits, was calculated by subtracting measured weight at each visit from self-reported prepregnancy weight. Weight gain was classified as under, within, or exceeding the Institute of Medicine recommendations based on prepregnancy body mass index. Chi-square tests and generalized linear mixed models were used to test for significant differences in percentages of participants within recommended weight gain ranges. Results. Differences in percentages of participants within the gestational weight gain guidelines were not significant between treatment arms across all visits. Conclusions. Enhancing the gestational nutrition and physical activity components of an existing home visiting program is feasible in a high risk population of primarily low income African American women. The impact of these enhancements on appropriate gestational weight gain is questionable given the more basic living needs of such women. This trial is registered with ClinicalTrials.gov NCT01746394, registered 4 December 2012.

The Suspected Macrosomic Fetus at Term: A Clinical Dilemma

Estimation of fetal weight is an important component of antenatal and intrapartum management of pregnant women. While many clinicians use ultrasound estimates of fetal weight to assess fetal growth, there are inherent challenges in both the diagnosis and management of suspected fetal macrosomia. Given the inaccuracy in estimating fetal weight, and the risks that accompany cesarean birth or induction of labor, the management of suspected fetal macrosomia requires open communication and shared decision making between the woman and her health care providers. This case study and literature review highlight the current management and recommendations for suspected fetal macrosomia.

Early-pregnancy maternal vitamin D status and maternal hyperglycaemia

AIMS

To estimate the association between serum 25-hydroxyvitamin D concentrations and maternal hyperglycaemia (post-load glucose concentration ≥ 7.5 mmol/l).

METHODS

Pregnant women (n = 429; 61% black, 36% obese, 45% smokers) enrolled in a cohort study at <16 weeks gestation. Non-fasting blood samples were assayed for serum 25-hydroxyvitamin D at enrolment. At 24-28 weeks gestation, maternal hyperglycaemia was determined using a 50-g 1-h oral glucose challenge test.

RESULTS

A total of 67% of women had 25-hydroxyvitamin D concentrations < 50 nmol/l and 11% had maternal hyperglycaemia. Among smokers, each 23-nmol/l increase in serum 25-hydroxyvitamin D was associated with a reduction in the odds of maternal hyperglycaemia [odds ratio: 0.30 (95% CI: 0.13, 0.68)] after adjustment for parity, race/ethnicity, age, pre-pregnancy BMI, marital status, income, family history of diabetes, and gestational age of gestational diabetes mellitus screening. Among non-smokers, we found no association between early pregnancy vitamin D status and maternal hyperglycaemia.

CONCLUSIONS

Smoking status may modify the relationship between poor maternal vitamin D status and maternal hyperglycaemia.

Risk factors at birth for permanent obstetric brachial plexus injury and associated osseous deformities

Purpose. To examine the most prevalent risk factors found in patients with permanent obstetric brachial plexus injury (OBPI) to identify better predictors of injury. Methods. A population-based study was performed on 241 OBPI patients who underwent surgical treatment at the Texas Nerve and Paralysis Institute. Results. Shoulder dystocia (97%) was the most prevalent risk factor. We found that 80% of the patients in this study were not macrosomic, and 43% weighed less than 4000 g at birth. The rate of instrument use was 41% , which is 4-fold higher than the 10% predicted for all vaginal deliveries in the United States. Posterior subluxation and glenoid version measurements in children with no finger movement at birth indicated a less severe shoulder deformity in comparison with those with finger movement. Conclusions. The average birth weight in this study was indistinguishable from the average birth weight reported for all brachial plexus injuries. Higher birth weight does not, therefore, affect the prognosis of brachial plexus injury. We found forceps/vacuum delivery to be an independent risk factor for OBPI, regardless of birth weight. Permanently injured patients with finger movement at birth develop more severe bony deformities of the shoulder than patients without finger movement.

Birth injury in a subsequent vaginal delivery among women with a history of shoulder dystocia

AIM

To examine risk factors for birth injury in a subsequent vaginal delivery among women with a prior delivery complicated by shoulder dystocia.

METHODS

Population-based retrospective cohort study, Washington State (1987-2007). Logistic regression was used to assess risk factors associated with subsequent birth injury.

RESULTS

Of 9232 women who met inclusion criteria, 223 (2.4%) had a subsequent vaginal delivery with birth injury. Birth injury in an index delivery, adjusted odds ratio (aOR) 2.6 [95% confidence interval (CI) 1.7-4.1] and factors in subsequent delivery: birth weight ≥4000 g, aOR 4.4 (95% CI: 3.0-6.3), gestational diabetes, aOR 1.9 (95% CI: 1.2-3.2), Hispanic ethnicity aOR 1.9 (95% CI: 1.2-2.9), and maternal obesity, aOR 1.8 (95% CI: 1.3-2.6) were associated with birth injury.

CONCLUSION

Among women with prior delivery complicated by shoulder dystocia, the risk factors identified in this study should be carefully considered prior to deciding upon route of delivery - cesarean vs. vaginal delivery.

Intergenerational cycle of obesity and diabetes: how can we reduce the burdens of these conditions on the health of future generations?

Prepregnancy overweight or obesity and excessive gestational weight gain have been associated with increased risk of maternal and neonatal complications. Moreover, offspring from obese women are more likely to develop obesity, diabetes mellitus, and cardiovascular diseases in their lifetime. Gestational diabetes mellitus (GDM) is one of the most common complications associated with obesity and appears to have a direct impact on the future metabolic health of the child. Fetal programming of metabolic function induced by obesity and GDM may have intergenerational effect and thus perpetuate the epidemic of cardiometabolic conditions. The present paper thus aims at discussing the impact of maternal obesity and GDM on the developmental programming of obesity and metabolic disorders in the offspring. The main interventions designed to reduce maternal obesity and GDM and their ability to break the vicious circle that perpetuates the transmission of obesity and metabolic conditions to the next generations are also addressed.

Pregnancy complicated by obesity: midwifery management

Obesity-related comorbidities such as gestational diabetes and hypertension have the potential to affect at least 25% of women in the United States. Midwives have been caring for and collaboratively managing these conditions in nonobese women for decades. Prenatal weight gain advice should be based on pregravid body mass index and aim for the lower end of the 1990 Institute of Medicine prenatal weight gain ranges. Obese women may require extra ultrasound and blood glucose testing during pregnancy. Pregnancy complicated by obesity may limit the place and style of birth. Midwives can integrate management techniques into the perinatal care of women whose body mass indices exceed 29 to reduce risk and future disease for mothers and newborns.

Shoulder dystocia: using simulation to train providers and teams

Shoulder dystocia is an obstetric emergency that requires immediate recognition and a well-coordinated response. This response must include effective application of the maneuvers proven to relieve the impaction of the fetal shoulder and timely hand-off of the newborn to the neonatology team. The rare frequency of shoulder dystocia, coupled with patient safety concerns and the medico-legal environment, limits the opportunity of providers to learn and practice the management of shoulder dystocia. Training, especially simulation-based training, has been demonstrated to improve the management of shoulder dystocia. This article presents a review of the literature that supports simulation training for shoulder dystocia and provides guidance on creating and implementing shoulder dystocia training.

[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.

Shoulder dystocia: nursing prevention and posttrauma care

Shoulder dystocia is a birth emergency that occurs in approximately 1% of all births. Shoulder dystocia can be followed by broken clavicle or humerus, brachial plexus injury, fetal hypoxia, or death. Although risk factors for shoulder dystocia include previous birth complicated by shoulder dystocia, maternal obesity, excessive prenatal weight gain, fetal macrosomia, gestational diabetes, and instrumental delivery, shoulder dystocia is not predictable. Perinatal nurses can reduce the risk for shoulder dystocia by teaching mothers about optimal weight gain in pregnancy and assisting mothers with diabetes to prevent hyperglycemia through diet management and medication use. During childbirth preparation or early labor, nurses can educate mothers about position changes and maneuvers used for shoulder dystocia. Nurses play a vital role in obtaining assistance during a shoulder dystocia, keeping time, assisting with maneuvers such as suprapubic pressure, and documenting the dystocia management. Nurses can assist mothers and families to review the shoulder dystocia and any newborn injuries in the postpartum period, thereby reducing confusion and anxiety. Regular drills and case reviews help build nursing shoulder dystocia management skills.

Gestational Diabetes: A Review of the Current Literature and Guidelines

Despite large numbers of original research studies spanning 4 decades there is still no consensus on the subject of gestational diabetes. Should all pregnant women be screened or only those with risk factors? Or is it safe not to screen at all? Which screening test and which diagnostic test are the most reliable? Which cutoff values should we use? What are the risks involved for mother and baby and can treatment improve outcome? What is the connection between gestational diabetes and diabetes mellitus type II? Are there disadvantages to screening? A review of relevant articles shows that definitive answers to these questions are not yet available. There is no gold standard screening test and no threshold glucose value above which complications are markedly increased. On the contrary, there appears to be a continuum of slowly increasing risks with rising blood glucose values, where it seems difficult to draw a clear line between pathology and physiology. Moreover, treatment has thus far not been shown to significantly improve outcome. There seems to be an indistinct area between the diagnosis of gestational diabetes and diabetes mellitus type II, where women with risk factors for one are also predisposed to develop the other, thereby confusing the diagnosis. Finally, the disadvantages to diagnosing and treating women without a clearly proven benefit seem to be significant. Therefore it seems defensible to suspend all screening and treatment for gestational diabetes, or at least significantly raise the threshold for making a positive diagnosis and initiating treatment, until further research has proven a clear benefit.

TARGET AUDIENCE

Obstetricians & Gynecologists, Family Physicians.

LEARNING OBJECTIVES

After completion of this article, the reader should be able to summarize that there is still no worldwide consensus on the diagnosis, management, and adverse effects of Gestational Diabetes Mellitus (GDM); explain that all methods of screening vary in sensitivity and depend on very strict preparations for screening; state that there is no agreement on ideal levels of blood glucose to prevent untoward effects; and recall that there are two very large prospective studies that clarify the dark waters and that we should await their results.