Factors contributing to failure of vacuum delivery and associated maternal/neonatal morbidity.

OBJECTIVE To determine factors contributing to the failure of vacuum delivery and to compare the neonatal and maternal morbidity associated with failed and successful procedures. METHODS A retrospective case-control study was undertaken at Aga Khan University Hospital, Nairobi, Kenya, by review of medical charts from the period of January 2007 to December 2010. In total, 31 cases of failed vacuum delivery were compared with 124 controls where extraction was successful. The primary outcome measure was fetal malposition. Secondary outcome measures included a composite score of maternal complications, a 5-minute Apgar score below 7, an umbilical arterial pH below 7.1, and a base excess below -12. Multiple logistic regression analysis was undertaken to identify factors associated with failure of vacuum delivery. RESULTS Demographic and labor characteristics were similar in both groups. Fetal malposition significantly contributed to the failure of vacuum delivery (odds ratio 12.7, 95% confidence interval 1.5-14.8). Failure of vacuum delivery was not associated with clinically important neonatal or maternal morbidity. CONCLUSIONS Vacuum extraction is a safe mode of delivery where indicated, with minimal maternal and neonatal morbidity even in the event of procedural failure.