A Randomized Double-Blind Controlled Trial Comparing Rapid Versus Stepwise Negative Pressure Application for Vacuum Extraction Assisted Vaginal Delivery

Objective:To compare efficacy and complication of a rapid (one-step) with stepwise application of negative pressure for vacuum extraction. Materials and Methods: All pregnant women laboring in Health Promotion Hospital, Bangkok between October 1st, 2002 to September 30th, 2007 were simple randomised to be assisted by the rapid vacuum application (study group) or by the stepwise vacuum application technique (control group). Each had the suitable conditions for vacuum assisted delivery. Patients and obstetricians were blinded to the technique used. During the labour, the time for vacuum application, traction, and delivery were recorded. The effectiveness of methods of application, morbidity of mother and infant were evaluated by another doctor. Results: Three hundred and seventy pregnant women were randomizedly studied. There were no serious complications during or following the procedures in both groups. The both technique were no significant difference in cup detachment rate, procedure failure rate, birth passage injury, fetal injury, hyperbilirubinemia, breastfeeding failure, perineal pain after delivery, perineal wound infection and postpartum haemorrhage. The mean decreasing pressure time and traction time in study group (n=182) were 125.6 and 977.2 seconds respectively. Meanwhile, in the control group (n=188), the mean decreasing pressure time and traction time were 615.2 and 941.4 seconds respectively. The traction times were not different (p=0.29), but the total procedure times in study group were less than in control group (p<0.0001). The Apgar’s scores were not different between two groups,both at 1st and 5th minute (p=0.04,0.16 respectively). For the fetus delivering with the indication of fetal distress cases had less birth asphyxia in the study group than in control group (p<0.001) The traction time of two birth asphyxia groups were not different (p=0.23) but the application and total procedure time of both groups were significantly different (p<0.01, 0.01 respectively). Conclusion: Rapid application of vacuum not only has the same efficiency and safety as stepwise application but also be useful in the fetal distress cases because it has significantly shorter time of a vacuum extraction