Rapid versus stepwise application of negative pressure in vacuum extraction-assisted vaginal delivery: a multicentre randomised controlled non-inferiority trial. Stepwise compared with rapid application of vacuum in ventouse extraction procedures. A randomized comparison of assisted vaginal delivery by obstetric forceps and polyethylene vacuum cup. A randomised prospective trial of the obstetric forceps versus vacuum extraction using defined criteria. A randomised prospective study comparing the new vacuum extractor policy with forceps delivery. A randomised controlled trial of a new handheld vacuum extraction device. [Comparative assessment of efficacy and safety of assisted vaginal delivery with forceps and with vacuum extractor]. Forceps or vacuum extraction? A comparison of effects on the newborn infant. Comparison of intravenous oxytocin and vaginal prostaglandin E2 gel in women with unripe cervixes and premature rupture of the membranes.
To evaluate whether the application of rapid negative pressure for vacuum-assisted delivery is as effective and safe as the stepwise method.
                Randomised controlled trial.
                Six centres, including university, secondary and tertiary hospitals, in Thailand.
                In total, 662 women were randomised to rapid and stepwise groups, with 331 women in each group.
                Vacuum extraction was performed by applying a metal cup (Malmstrom) connected to an electric pump to the fetal head. The stepwise method consisted of four incremental steps of 0.2 kg/cm² every 2 minutes to obtain a final negative pressure of 0.8 kg/cm². In the rapid method the negative pressure of 0.8 kg/cm² was applied in one step in < 2 minutes.
                Success rate of vacuum extraction, vacuum cup detachment rate, duration of vacuum extraction, and maternal and neonatal complications.
                There were no significant differences in detachment rates (RD 0.3%, 95% CI -3.1 to 2.4). The overall success rates were identical, at 98.2%. There were significant reductions in the time between applying the vacuum cup and attaining maximum negative pressure (MD -4.6 minutes; 95% CI -4.4 to -4.8 minutes), and in the time between applying the cup and delivery (MD -4.4 minutes; 95% CI -4.8 to -4.0 minutes). There was a significantly higher rate of perineal suture in the rapid method group (RD 4.5%; 95% CI 1.1-8.2). There were no significant differences in maternal and fetal morbidities.
                Rapid negative pressure vacuum extraction could be performed as effectively and safely as the stepwise method, in a shorter period of time.
                © 2011 The Authors BJOG An International Journal of Obstetrics and Gynaecology © 2011 RCOG. To compare a one-step (rapid) application of negative pressure (vacuum) with conventional stepwise application for ventouse extraction following a prolonged second stage of labour.
                Randomised controlled study.
                Teaching Hospital.
                Forty-seven women were randomised to the rapid vacuum group and 47 to the stepwise group.
                Duration of ventouse procedure, effectiveness of methods of application, morbidity of mother and infant.
                There was no significant difference in frequency of detachment of the cup after rapid or stepwise application of vacuum. A reduction in mean duration of the ventouse procedure of 6 min was realised without significant difference in maternal or neonatal morbidity.
                Rapid application of vacuum significantly reduces the duration of a ventouse extraction procedure without compromise to efficiency and safety. The assisted vaginal delivery methods of rigid obstetric forceps and polyethylene vacuum cup extraction were compared in a prospective, randomized study. The 99 women studied had all completed 35 full weeks' gestation, required attempted assisted vaginal delivery, and were randomly assigned to either attempted forceps or vacuum-assisted delivery. All presentations were cephalic, with stations ranging from +1 to +4. Neonates were evaluated at 24 hours by neonatal staff. The infants underwent intracranial ultrasound screening during the first 24 hours of life and ophthalmologic examination within 48 hours. Vaginal delivery was successful with the intended method in 83% of vacuum-assisted deliveries and in 78% of forceps deliveries (not statistically significant). Neonatal retinal hemorrhage was found in 17 and 38% (P less than .043) of the randomized forceps and vacuum deliveries, respectively. No intraventricular hemorrhage was found. Apart from associations between vacuum-assisted delivery and mild hyperbilirubinemia and neonatal retinal hemorrhage (of uncertain clinical significance), and between assisted forceps delivery and an increased potential for facial injury, neonatal outcomes did not differ significantly. Maternal outcomes also did not differ significantly. No significant differences in safety or efficacy were found between polyethylene cup vacuum extraction and rigid obstetric forceps-assisted vaginal delivery in this population of predominantly low-pelvic assisted deliveries. Patients delivered by sequential use of forceps after vacuum or by vacuum after failed forceps application did not suffer significantly increased morbidity relative to those delivered by forceps or vacuum alone. Use of alternate or sequential methods allowed an overall cesarean rate of 3% in this population. The objective of this study was to determine the safety of obstetrics forceps when used under strictly defined criteria compared to vacuum extraction for delivery in the second stage of labour. A randomised prospective trial was performed on 442 women undergoing instrumental delivery in the second stage. Two hundred and four women were in the forceps group and 238 in the vacuum group. When using forceps traction efforts to deliver the baby were kept to less than three and the head was always delivered in the occipito-anterior position. In the two groups there were no significant difference in the incidence of third-degree perineal tears, post-partum haemorrhage or ruptured uterus. Cervical tears were slightly higher in the forceps group. Babies delivered by vacuum extraction showed a higher incidence of cephalhaematomas. There was no significant difference in babies needing resuscitation at birth, admission to neonatal intensive care unit, stillbirth or neonatal death rates. The failure rate was significantly higher in the vacuum group. The time taken to complete the procedure was significantly less in the forceps group. Forceps deliveries when performed under defined criteria are as safe as vacuum deliveries to the mother with a lesser failure rate and a lower incidence of cephalhaematomas in the neonate compared with vacuum deliveries. To compare assisted vaginal delivery by forceps with delivery by vacuum extractor, where a new vacuum extractor policy was employed which dictated the cup to be used in specific situations.
                Multicentre randomised controlled trial.
                Four district general hospitals in the West Midlands.
                Six hundred-seven women requiring assisted vaginal delivery, of whom 296 were allocated to vacuum extractor delivery and 311 to forceps.
                Delivery success rate, maternal perineal and vaginal injuries, maternal anaesthetic requirements, neonatal scalp and facial injuries.
                Of the vacuum extractor group, 85% were delivered by the allocated instrument compared to 90% in the forceps group (odds ratio (OR) 0.64; 95% confidence intervals (CI) 0.4-1.04). However, more women in the vacuum extractor group were delivered vaginally (98%) than in the forceps group (96%). There were significantly fewer women with anal sphincter damage or upper vaginal extensions in the vacuum extractor group (11% vs 17%, OR 0.6; 95% CI, 0.38-0.97). There were significantly fewer women in the vacuum extractor group requiring epidural or spinal anaesthetics (25.4% vs 32.7%, OR 0.69; 95% CI 0.49-0.99) or general anaesthetics (1% vs 4%, OR 0.17; 95% CI 0.04-0.76). Although there were significantly more babies in the vacuum extractor group with cephalhaematomata (9% vs 3%, OR 3.3; 95% CI 1.4-7.4) there were fewer babies in the vacuum extractor group with other facial injuries. There were three babies in the forceps group with unexplained neonatal convulsions.
                Assisted vaginal delivery using the new vacuum extractor policy is associated with significantly less maternal trauma than with forceps. Further studies are required to assess neonatal morbidity adequately. To evaluate the effectiveness of a new handheld vacuum delivery device.
                Randomised controlled trial.
                Southmead Hospital, Bristol, UK.
                One hundred and ninety-four women requiring delivery with vacuum extraction.
                Women were recruited into the study while still in early labour. If during delivery, vacuum extraction was indicated they were then randomly allocated to either a new handheld vacuum device, the Kiwi Omnicup, or to a 'standard' vacuum cup selected by the obstetrician. The 'standard group' consisted of the silastic (66/98, 67%) or the metal cups (32/98, 33%). Study data were recorded at completion of the delivery and at 24-48 hours. An additional brief symptom questionnaire was completed by the mother at 10 days postnatally. Statistical analyses were done on an 'intention-to-treat' basis.
                The primary outcome was the successful completion of delivery with the allocated instrument. Secondary outcomes were substantial fetal scalp trauma and substantial maternal trauma.
                The Omnicup was associated with a significantly higher failure rate than the standard cup [34%vs 21%, odds ratio (OR) = 1.9 (1.01-3.6)]. This difference persisted after adjusting for confounding factors [adjusted OR = 2.25 (1.01-5.0)] and resulted in significantly more forceps deliveries in the Kiwi Omnicup group [22%vs 10%, unadjusted OR = 2.5 (1.1-5.5)]. The caesarean section rates were similar in both groups [9.4%vs 8.2%, OR = 1.2 (0.4-3.2)]. Rates of substantial scalp trauma and maternal trauma were similar in both groups. However, there were more cases of jaundice in the standard cup group [2.3%vs 12.0%, unadjusted OR = 0.18 (0.04-0.82) and adjusted OR = 0.10 (0.01-0.88)].
                The Omnicup is not as successful at achieving a vaginal delivery as the combination of the currently used vacuum cups. We performed a prospective, controlled, randomized trial to compare de safety and efficacy between the vaginal assisted delivery with vacum extractor forceps. We included a control group of primigravidae. We use the ACOG application criteria for operative obstetrics. We measured the differences in regard to indication for operative delivery, obstetric trauma and the general characteristics of the patients. A total of 210 patients were included which were distributed in three groups. In the first group we included the patients of vacum extractor, the second group of forceps and the third the control group. In our results we found no statistically significant differences among three groups in regard to the general characteristics and obstetric trauma. In the vacum extractor group we found six cefalohematomas (8.5%), two newborns with skin laceration (2.8%) and four newborns with cerebral edema (5.7%). In the forceps group we had two newborns diagnosed with cefalohematomas (2.8%), seven newborns with cerebral edema (10%) and scalp laceration on four newborns (6%). In the control group we found one cefalohematoma (1.4%) and cerebral edema in four newborns (5.7%). We did not find statistically significant differences when we compared the group of the vacum and the forceps.
                With this information we concluded that both instruments are equal in regard to efficacy and safety when they are use by experimented hands and following the application criteria. Nevertheless, there is a high incidence of vaginal injuries and obstetric trauma in the newborn in the operative delivery compared with the control group without an important increase in the perinatal mortality. Sixteen women delivered by forceps and 20 women delivered by vacuum extraction (VE) owing to secondary uterine inertia were compared with a control group of 11 women who gave birth spontaneously. The cord arterial pH was lower in the VE group than in the forceps and control groups. Base deficit in both arterial and venous cord blood was greater in the VE group than in the forceps group, probably owing to the longer application and extraction times in VE than in forceps delivery. The incidence of retinal hemorrhage did not differ between the forceps and VE groups. The incidence of cephalhematomata was greater among VE infants than in the forceps and control groups. All infants were examined on the 1st and 5th day by standardized neurological and behavioural examination. There were no significant differences in neurological status between the forceps and VE groups. Thus, in low extraction with no signs of fetal asphyxia, either method can be used with safety if the obstetrician is familiar with both methods of operative vaginal delivery. To induce cervical priming and labor, 20 nulliparous term pregnant women with premature rupture of the membranes and unfavorable cervical states were randomly given either oxytocin intravenously or 4 mg prostaglandin E2 in gel intravaginally. One of ten women receiving oxytocin had a favorable cervical state within five hours and vaginal delivery within 24 hours after the start of the infusion compared with six of ten women after prostaglandin E2 gel application. This difference is statistically significant (P less than .01). The number of instrumental deliveries was nine (four cesarean sections and five vacuum extractions) in the oxytocin-treated patients compared with only two vacuum extractions in women who received prostaglandin E2 gel. This difference is also statistically significant (P less than .01, Fischer exact test). In a subsequent open study, 4 mg prostaglandin E2 gel was applied vaginally to 17 term pregnant women of mixed parity with premature rupture of the membranes and unfavorable cervixes. In 12 women a favorable cervical state was achieved within five hours after gel application, and all these women were delivered within 24 hours. None of the women required cesarean section but two required delivery by vacuum extraction. There were no perinatal losses, but two infants in the oxytocin-treated group had Apgar scores less than 7 at five minutes. At pediatric follow-up after two and six months, all infants were normal. In both obstetric and perinatal outcome prostaglandin E2 gel thus seems to be superior to oxytocin for labor induction in term pregnant patients with premature rupture of the membranes and unfavorable cervixes.
The rapid negative pressure application for vacuum assisted vaginal birth reduces duration of the procedure whilst there is no evidence of differences in maternal and neonatal outcomes. Rapid method of negative application should be recommended for vacuum extraction assisted vaginal delivery.