• 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.