Brachial Plexus Birth Injury in the Preterm Infant: Suspecting the Unsuspected.

Background: Prematurity is usually considered as a protective factor for brachial plexus birth injury (BPBI). However, BPBI can occur in the preterm infant, and can cause significant dysfunction and morbidity. There is scant literature regarding this subgroup of patients with BPBI.

Methods: Patients were identified through a retrospective search of a prospective BPBI registry at a single tertiary pediatric referral center. Prematurity was defined as birth at or before gestational age of 36 (6/7) weeks. Thirty-six arms in 34 patients were included in this study. Data were obtained from patient charts documenting standardized brachial plexus clinical examinations at each visit, medical imaging, questionnaires for parents, and outside perinatal records brought in by parents.

Results: The youngest infant identified with BPBI was born at 23 weeks' gestation. Median birth weight was 3005 g (range: 580 to 4600 g). Twenty-nine arms in 28 patients were categorized into the "late preterm group" [34 to 36 (6/7) weeks gestation], and 7 arms in 6 patients were categorized into the "early preterm group" (<34 wk). Four of 6 (67%) subjects in the early preterm group were delivered vaginally in the breech position, compared with 4 of 28 subjects (14%) in the late preterm group (P=0.02). All 3 twin gestation infants with BPBI were the younger twin and born vaginally in the breech position. Delayed diagnosis (>7 d) occurred in 11 arms in 10 subjects (31%). Median delay in diagnosis was 73 days (range: 10 to 1340 d). Spontaneous recovery of antigravity elbow flexion occurred in 65% of arms (at median 5 mo, range: 1 to 17 mo). Overall, 89% (32/36) of arms with BPBI had residual neurological deficit and 53% (19/36) of arms underwent at least 1 surgical intervention at latest follow-up (median age at latest follow-up: 60 mo, range: 1 to 237 mo).

Conclusions: BPBI in preterm infants is rare but does occur and can cause significant morbidity. Delayed diagnosis of BPBI is common in preterm infants. A high index of suspicion should be maintained to avoid delayed diagnosis that may jeopardize treatment options. Preterm infants may be more susceptible to birth trauma from breech deliveries and shoulder dystocia, as evidenced by far higher incidence of these factors compared with term infants with BPBI in literature.

Level Of Evidence: Level IV-case series.