Prepregnancy body mass index in non-diabetic women with and without shoulder dystocia

Contemporary Management of Shoulder Dystocia

Shoulder dystocia is an uncommon but potentially catastrophic intrapartum event. Although risk factors such as maternal diabetes, obesity and macrosomia can be identified, shoulder dystocia most frequently occurs in patients who lack risk factors. Many maneuvers have been described to assist the operator in the safe release of the shoulder and subsequent delivery; however, no prospective trials have compared these maneuvers in such a way to suggest that one maneuver is superior to another. This article describes the identification of patients at risk for shoulder dystocia, clinical management of the shoulder dystocia, event documentation and the contemporary use of drills and simulation training to improve team preparedness for this unpredictable and usually unavoidable event.

Determining factors associated with shoulder dystocia: a population-based study

OBJECTIVE

The study was aimed to define obstetric factors associated with shoulder dystocia.

METHODS

A population-based study comparing all singleton, vertex, term deliveries with shoulder dystocia with deliveries without shoulder dystocia was performed. Statistical analysis was done using multiple logistic regression analysis.

RESULTS

Shoulder dystocia complicated 0.2% (n = 245) of all deliveries included in the study (n = 107965). Independent risk factors for shoulder dystocia in a multivariable analysis were birth-weight > or =4000 g (OR = 24.3; 95% CI 18.5-31.8), vacuum delivery (OR = 5.7, 95% CI 3.4-9.5), diabetes mellitus (OR = 1.7, 95% CI 1.2-2.5) and lack of prenatal care (OR = 1.5, 95% CI 1.1-2.3). A significant linear association was found between birth-weight and shoulder dystocia, using the Mantel-Haenszel procedure. Pregnancies complicated with shoulder dystocia had higher rates of third-degree perineal tears as compared to the comparison group (0.8% versus 0.1%; P < 0.001). Similarly, perinatal mortality was higher among newborns delivered after shoulder dystocia as compared to the comparison group (3.7% versus 0.5%; OR = 7.4, 95% CI 3.5-14.9, P < 0.001). In addition, these newborns had higher rates of Apgar scores lower than 7 at 1 and 5 min as compared to newborns delivered without shoulder dystocia (29.7% versus 3.0%; OR = 13.8, 95% CI 10.3-18.4, P < 0.001 and 2.1% versus 0.3%; OR = 7.2, 95% CI 2.8-18.1, P < 0.001, respectively). Combining risk factors such as large for gestational age, diabetes mellitus and vacuum delivery increased the risk for shoulder dystocia to 6.8% (OR = 32.6, 95% CI 10.1-105.8, P < 0.001).

CONCLUSIONS

Independent factors associated with shoulder dystocia were birth-weight > or =4000 g, vacuum delivery, diabetes mellitus and lack of prenatal care.

Intrapartum risk factors for permanent brachial plexus injury

OBJECTIVE

The purpose of this study was to compare maternal, neonatal, and second stage of labor characteristics in shoulder dystocia deliveries that result in permanent brachial plexus injury with shoulder dystocia deliveries that result in no injury.

STUDY DESIGN

Our cases were culled from a database of deliveries that resulted in permanent brachial plexus injuries and matched to control cases that were taken from a database of consecutive shoulder dystocia deliveries from one hospital. Deliveries that resulted in injury were excluded from the control cases; those cases with no recorded shoulder dystocia were excluded from the cases. Matching was for birth weight (+/-250 g), parity, and diabetic status. Rates of precipitous and prolonged second stage, operative delivery, neonatal depression, and average number of shoulder dystocia maneuvers used were compared between the two groups with chi(2) test, Fisher exact test, and the Student t test; a probability value of <.05 was considered significant.

RESULTS

There were 80 matched patients, of which 26 patients were nulliparous and 11 patients were diabetic. Mothers of the uninjured group were younger than those of the injured group (23.7+/-6.2 years vs 27.4+/-5.1 years, P<.001). The injured group had a significantly higher rate of 5-minute Apgar scores of <7 (13.9% vs 3.8%, P=.04). Differences in maternal weight, body mass index, height, race, gestational age, average number of maneuvers, head-to-body delivery interval, operative delivery rate, prolonged second stage rate, precipitous second stage rate, and sex were not significant between groups. The rates of precipitous second stage for both groups (28.0% injured and 35.0% uninjured) were more than triple the rates of prolonged second stage (9.5% injured and 11.3% uninjured).

CONCLUSION

No characteristic of second-stage of labor predicts permanent brachial plexus injury. Precipitous second stage is the most prevalent labor abnormality that is associated with shoulder dystocia.