Clinical and sonographic risk factors and complications of shoulder dystocia - a case-control study with parity and gestational age matched controls.
OBJECTIVE
To examine the clinical risk factors and complications of shoulder dystocia today and to evaluate ultrasound methods predicting it.


METHODS
Retrospective, matched case-control study at a University Hospital with 5000 annual deliveries. The study population consisted of 152 deliveries complicated by shoulder dystocia over a period of 8.5 years (January 2004-June 2012) and 152 controls matched for gestational age and parity. The data was collected from the medical records of mothers and children and analyzed by conditional logistic regression. Incidences and odds ratios were calculated for risk factors and complications. Antenatal ultrasound data was analyzed when available by conditional logistic regression to test for significant differences between study groups.


RESULTS
Birthweight (OR 12.1 for ≥4000 g; 95% CI 4.18-35.0) and vacuum extraction (OR 3.98; 95% CI 1.25-12.7) remained the most significant clinical risk factors. Only a trend of an association of pregestational or gestational diabetes was noticed (OR 1.87; 95% CI 0.997-3.495, probability of type II error 51%). Of the complications of shoulder dystocia the incidence of brachial plexus palsies was high (40%). Antenatal ultrasound method based on the difference between abdominal and biparietal diameters had a significant difference between cases and controls.


CONCLUSIONS
The impact of diabetes as a risk factor has diminished, which may reflect improved screening and treatment. Antenatal ultrasound methods are showing some promise, but the predictive value of ultrasound alone is probably low.
School of Medicine, University of Tampere, Tampere 33014, Finland. Electronic address: jukka.parantainen@uta.fi.
Jukka
J
Parantainen
Department of Obstetrics and Gynecology, University Hospital of Tampere, PL 2000, Tampere 33521, Finland. Electronic address: outi.palomaki@pshp.fi.
Outi
O
Palomäki
School of Health Sciences, University of Tampere, Tampere 33014, Finland. Electronic address: nina.talola@uta.fi.
Nina
N
Talola
Department of Obstetrics and Gynecology, University Hospital of Tampere, PL 2000, Tampere 33521, Finland. Electronic address: jukka.uotila@pshp.fi.
Jukka
J
Uotila
D000328:Adult; D001720:Birth Injuries / Q000209:etiology; D001724:Birth Weight; D020516:Brachial Plexus Neuropathies / Q000209:etiology; D016022:Case-Control Studies; D002968:Clavicle / Q000293:injuries; D003924:Diabetes Mellitus, Type 2 / Q000453:epidemiology; D016640:Diabetes, Gestational / Q000453:epidemiology; D004420:Dystocia / Q000000981:diagnostic imaging* / Q000453:epidemiology*; D005260:Female; D050723:Fractures, Bone / Q000209:etiology; D005865:Gestational Age; D006801:Humans; D007231:Infant, Newborn; D010298:Parity; D011247:Pregnancy; D012307:Risk Factors; D012680:Sensitivity and Specificity; D012782:Shoulder; D014463:Ultrasonography; D014620:Vacuum Extraction, Obstetrical; D055815:Young Adult
Diabetes; Gestational; Obstetric; Paralysis; Shoulder dystocia; Ultrasonography