Brachial Plexus Birth Injury: Epidemiology and Birth Weight Impact on Risk Factors

Brachial plexus birth injury (BPBI) is a condition in which the brachial plexus is thought to be damaged during the birth process. Studies have cited a varying incidence rate ranging from 0.5 to 4.0 per 1000 live births. The purpose of this study is to evaluate birth claims data over a 15-year period to identify risk and protective factors for BPBI in the state of Colorado.

A data request was made to the state hospital association for birth claims data. We requested all birth claims from the years 2000 to 2014. ICD9 codes for variables of interest included: BPBI, shoulder dystocia, heavy-for-dates, macrosomia, breech delivery, instrumented birth, birth hypoxia, and gestational diabetes. A multivariable logistic regression model quantified both risk and protective factors for the development of BPBI as odds ratios (ORs) with 95% confidence intervals (CI).

There were 966,447 birth records received from State Hospital Association. The BPBI incidence was 0.63/1000 live births. The mean (SD) birth weight was 3187 (572) g for the total population and 3808 (643) g for the BPBI births. Later admission year indicated a decrease in BPBI births (OR, 0.94; 95% CI: 0.92, 0.96/y). Asian, black, and Hispanic infants were more likely to have a BPBI than white infants. Shoulder dystocia (OR, 60.37; 95% CI: 47.90, 76.13) was the highest risk factor for BPBI followed by instrumented forceps birth (OR, 21.04; 95% CI: 12.22, 36.21), breech delivery (OR, 15.38; 95% CI: 5.60, 42.25), and gestational diabetes (OR, 4.46; 95% CI: 3.29, 6.57). Cesarean single births had the lowest risk for BPBI (0.27; 95% CI: 0.20, 0.37), whereas cesarean multiple births (2.33; 95% CI: 1.10, 4.94) and natural multiple births (3.20; 95% CI: 1.36, 7.55) were at higher risk when compared with natural single births and all were statistically significant at P<0.027. Colorado births had a decreased risk of BPBI compared with the United States each year from 2000 (0.82/1000 births vs. 1.6/1000 live births, P<0.001) to 2012 (0.56/1000 live births vs. 0.9/1000 live births, P=0.003).

BPBI has decreased from 2000 to 2014. Historically Colorado has had a lower BPBI incidence than the United States. Shoulder dystocia, instrumented forceps birth, gestational diabetes, and breech delivery are the biggest predictors for BPBI. Increased awareness of shoulder dystocia and instrumented birth are hypothesized to have reduced these incidences. Nonwhites and Medicaid patients seem to be at higher risk for BPBI.

Level II-Prognostic.