Precision of vacuum cup placement and its association with subgaleal hemorrhage and associated morbidity in term neonates.

Purpose: To evaluate whether the precision of vacuum cup placement is associated with failed vacuum extraction(VE), neonatal subgaleal hemorrhage(SGH) and other VE-related birth trauma.

Methods: All women with singleton term cephalic fetuses with attempted VE were recruited over a period of 30 months. Neonates were examined immediately after birth and the position of the chignon documented to decide whether the cup position was flexing median or suboptimal. Vigilant neonatal surveillance was performed to look for VE-related trauma, including subgaleal/subdural hemorrhages, skull fractures, scalp lacerations. CT scans of the brain were ordered liberally as clinically indicated.

Results: The VE rate was 5.89% in the study period. There were 17(4.9%) failures among 345 attempted VEs. Thirty babies suffered from subgaleal/subdural hemorrhages, skull fractures, scalp lacerations or a combination of these, giving an incidence of VE-related birth trauma of 8.7%. Suboptimal cup positions occurred in 31.6%. Logistic regression analysis showed that failed VE was associated with a non-occipital anterior fetal head position (OR 3.5, 95% CI 1.22-10.2), suboptimal vacuum cup placement (OR 4.13, 95% CI 1.38-12.2) and a longer duration of traction (OR 8.79, 95% CI 2.13-36.2); while, VE-related birth trauma was associated with failed VE (OR 3.93, 95% CI 1.08-14.3) and more pulls (OR 4.07, 95% CI 1.98-8.36).

Conclusion: Suboptimal vacuum cup positions were related to failed VE but not to SGH and other vacuum-related birth trauma. While optimal flexed median cup positions should be most desirable mechanically to effect delivery, such a position does not guarantee prevention of SGH.