Risk factors for obstetric brachial plexus palsy among neonates delivered by vacuum extraction.
OBJECTIVE
The risk of obstetric brachial plexus palsy (OBPP) is increased in infants delivered instrumentally. The aim of this study was to identify risk factors for OBPP and to evaluate the association between possible risk factors linked to the duration of the vacuum extraction procedure and the subsequent risk.


METHODS
A population-based retrospective design was adopted. Using a national registry of operative vaginal deliveries linked to the Medical Birth Registry in Sweden, we evaluated by univariate and multiple logistic regression analyses the risk factors for OBPP in 13,716 women delivered by vacuum extraction. The variables assessed in the multiple logistic regression analysis were shoulder dystocia, fetal birth weight of 3,999 g or greater, fundal pressure, number of tractions, vacuum application time, parity, vacuum silicone cup, epidural anesthesia, and fetal head at the level of the ischial spines at vacuum application time.


RESULTS
Obstetric brachial plexus palsy was recorded in 153 (1.1%) infants. The following variables increased significantly the risk of OBPP in the newborn: shoulder dystocia (odds ratio 16.0; 95% confidence interval 8.9-28.7), fetal birth weight of 3,999 g or greater (7.1; 4.8-10.5), and administration of fundal pressure (1.6; 1.1-2.3). The probability of the risk of OBPP in vacuum-assisted deliveries increased in relation to vacuum extraction time (minutes).


CONCLUSIONS
Shoulder dystocia in the setting of vacuum extraction is a prominent risk factor for OBPP in the newborn. The risk of OBPP increases with the time required for vacuum extraction.


METHODS
II-3.
Mollberg
Margareta
M
Perinatal Center, Department of Obstetrics and Gynecology, Institute for the Health of Women and Children, Sahlgrenska University Hospital, S-416 85 Göteborg, Sweden. margareta.mollberg@vgregion.se
Hagberg
Henrik
H
Bager
Börje
B
Lilja
Håkan
H
Ladfors
Lars
L
D000328:Adult; D001720:Birth Injuries / Q000209:etiology*; D020516:Brachial Plexus Neuropathies / Q000209:etiology*; D005260:Female; D006801:Humans; D007231:Infant, Newborn; D016015:Logistic Models; D012189:Retrospective Studies; D012307:Risk Factors; D013997:Time Factors; D014620:Vacuum Extraction, Obstetrical / Q000009:adverse effects*