Etiological risk factors for brachial plexus palsy

Aim. To investigate risk factors for brachial plexus palsy in newborns. We analyzed 45 544 live-born children, born over a nine-year period from January 1, 1996 to December 31, 2004. Methods. The analysis was retrospective and based on the medical documentation of the Clinic for Gynecology and Obstetrics, Clinic for Neurology, and Clinic for Physical Medicine and Rehabilitation of the University Clinical Center Tuzla. We compared study and control groups of newborns. Rates among groups were compared using Chi-square, with significance at p < 0.05, and with significance at p < 0.01. Results. Examining epidemiological characteristics, 86 newborns with brachial plexus palsy had been recorded, thus, the prevalence was 1.86 per 1000 live-born children. Analyzing maternal and neonatal factors, and the labor pattern itself, it was found that the highest factors of risk for brachial plexus injury were birth weight of over 4000 g, a precipitous second stage of labor (<15 minutes), and vacuum-extractor assisted labor. Brachial plexus palsy was more frequent when the mothers were overweight, with a body mass index ≥29 kg/m2. None of the parturient women, whose newborns were diagnosed with brachial plexus palsy, had external conjugate diameter <18 cm. Newborns delivered vaginally were not diagnosed with a higher frequency of brachial plexus palsy when compared to newborns who were delivered by cesarean section, but newborns who were vaginal breech-delivered were diagnosed to have a higher incidence of brachial plexus palsy. Newborns whose mothers were older than 35 years were diagnosed to have brachial plexus palsy more frequently, but a statistically significant difference between primiparas and multiparas was not found. A total of 39 newborns (45.2%) were diagnosed with a fracture of the clavicle, which was the most frequently combined damage with brachial plexus injury. Forty-two newborns (48.8%) had an Apgar score of ≤7 in the first minute after delivery, which indicates intrapartal fetal distress and is an indication of the traumatic nature of these deliveries. The average birth weight of newborns with brachial plexus damage was 3858.1±587.7 g, which for an average gestational age of 38.8±1.8 weeks, corresponds to eutrophic newborns. Both male and female newborns were diagnosed to have brachial plexus palsy comparably frequently, and almost all deliveries (97.7%) were initiated spontaneously. The majority of newborns were born between the hours of 02:00 and 03:00 and between the hours of 14:00–15:00.