Fetal rotation during vacuum extractions for prolonged labor: a prospective cohort study.

INTRODUCTION: The aim of the study was to investigate fetal head rotation during vacuum extraction. MATERIAL AND METHODS: We conducted a prospective cohort study from November 2013 to July 2016 in seven European hospitals. Fetal head position was determined with transabdominal or transperineal ultrasound and categorized as occiput anterior (OA), occiput transverse (OT) or occiput posterior (OP) position. Main outcome was the proportion of fetuses rotating during vacuum extraction. Secondary outcomes were conversion of delivery method, duration of vacuum extraction, umbilical artery pH <7.10 and agreement between clinical and ultrasound assessments. RESULTS: The study population comprised 165 women. During vacuum extraction 117/119 (98%) remained in OA and two fetuses rotated to OP position. Rotation from OT to OA position occurred in 14/19 (74%) and to OP position in 5/19 (26%). Rotation from OP to OA position occurred in 15/25 (60%), and 10/25 (40%) fetuses remained in OP position. Delivery information was missing in two cases. The conversion rate from vacuum extraction to cesarean section or forceps was 10% in the OA group vs. 23% in the non-OA group; p < 0.05. The estimated duration of vacuum extraction was significantly shorter in OA fetuses, 7 min vs. 10 min (log rank test p < 0.01). There was no significant difference in umbilical artery pH < 7.10 between OA and non-OA position. Cohens Kappa of agreement between clinical and ultrasound assessments was 0.42 (95% CI 0.26-0.57). CONCLUSION: Most fetuses in OP or OT positions rotated to OA position during vacuum extraction, but the proportion of failed vacuum extractions remained high.

Sonographic prediction of outcome of vacuum deliveries: a multicenter, prospective cohort study.

BACKGROUND: Safe management of the second stage of labor is of great importance. Unnecessary interventions should be avoided and correct timing of interventions should be focused. Ultrasound assessment of fetal position and station has a potential to improve the precision in diagnosing and managing prolonged or arrested labors. The decision to perform vacuum delivery is traditionally based on subjective assessment by digital vaginal examination and clinical expertise and there is currently no method of objectively quantifying the likelihood of successful delivery. Prolonged attempts at vacuum delivery are associated with neonatal morbidity and maternal trauma, especially so if the procedure is unsuccessful and a cesarean is performed. OBJECTIVE: The aim of the study was to assess if ultrasound measurements of fetal position and station can predict duration of vacuum extractions, mode of delivery, and fetal outcome in nulliparous women with prolonged second stage of labor. STUDY DESIGN: We performed a prospective cohort study in nulliparous women at term with prolonged second stage of labor in 7 European maternity units from 2013 through 2016. Fetal head position and station were determined using transabdominal and transperineal ultrasound, respectively. Our preliminary clinical experience assessing head-perineum distance prior to vacuum delivery suggested that we should set 25 mm for the power calculation, a level corresponding roughly to +2 below the ischial spines. The main outcome was duration of vacuum extraction in relation to ultrasound measured head-perineum distance with a predefined cut-off of 25 mm, and 220 women were needed to discriminate between groups using a hazard ratio of 1.5 with 80% power and alpha 5%. Secondary outcomes were delivery mode and umbilical artery cord blood samples after birth. The time interval was evaluated using survival analyses, and the outcomes of delivery were evaluated using receiver operating characteristic curves and descriptive statistics. Results were analyzed according to intention to treat. RESULTS: The study population comprised 222 women. The duration of vacuum extraction was shorter in women with head-perineum distance ≤25 mm (log rank test <0.01). The estimated median duration in women with head-perineum distance ≤25 mm was 6.0 (95% confidence interval, 5.2-6.8) minutes vs 8.0 (95% confidence interval, 7.1-8.9) minutes in women with head-perineum distance >25 mm. The head-perineum distance was associated with spontaneous delivery with area under the curve 83% (95% confidence interval, 77-89%) and associated with cesarean with area under the curve 83% (95% confidence interval, 74-92%). In women with head-perineum distance ≤35 mm, 7/181 (3.9%) were delivered by cesarean vs 9/41 (22.0%) in women with head-perineum distance >35 mm (P <.01). Ultrasound-assessed position was occiput anterior in 73%. Only 3/138 (2.2%) fetuses in occiput anterior position and head-perineum distance ≤35 mm vs 6/17 (35.3%) with nonocciput anterior position and head-perineum distance >35 mm were delivered by cesarean. Umbilical cord arterial pH <7.10 occurred in 2/144 (1.4%) women with head-perineum distance ≤35 mm compared to 8/40 (20.0%) with head-perineum distance >35 mm (P < .01). CONCLUSION: Ultrasound has the potential to predict labor outcome in women with prolonged second stage of labor. The information obtained could guide whether vacuum delivery should be attempted or if cesarean is preferable, whether senior staff should be in attendance, and if the vacuum attempt should be performed in the operating theater.

Duration of the active phase of labor in spontaneous and induced labors.

INTRODUCTION: The aim of the study was to compare the duration of active phase of labor in women with spontaneous or induced start of labor. MATERIAL AND METHODS: An observational cohort study was performed at Stavanger University Hospital in Norway between January 2010 and December 2013. During the study period 19 524 women delivered. Data for the study were collected from an electronic birth journal. Women with previous cesarean section, multiple pregnancy, breech or transverse lie, preterm labor or prelabor cesarean section were excluded. Analyses were stratified between nulliparous and parous women. Active phase of labor was defined when contractions were regular, with cervix effaced and dilated 4 cm. The main outcome measure was duration of active phase of labor. RESULTS: The active phase was longer in induced labors than in labors with spontaneous onset in nulliparous women. The estimated median duration using survival analyses was 433 min (95% confidence interval 419-446) in spontaneous vs. 541 min (95% confidence interval 502-580) in induced labors [unadjusted hazard ratio 0.76 (95% confidence interval 0.71-0.82) and adjusted hazard ratio 0.88 (95% confidence interval 0.82-0.95)]. In parous women, a one minus survival plot showed that induced labors had shorter duration before six hours in active labor, but after six hours, induced labors had longer duration. The overall difference in parous women was small and probably of little clinical importance. CONCLUSION: The active phase of labor was longer in induced than in spontaneous labors in nulliparous women.

Judicious use of oxytocin augmentation for the management of prolonged labor.

INTRODUCTION: A protocol including judicious use of oxytocin augmentation was investigated to determine whether it would change how oxytocin was used and eventually influence labor and fetal outcomes. MATERIAL AND METHODS: The population of this cohort study comprised 20 227 delivering women with singleton pregnancies ≥37 weeks, cephalic presentation, spontaneous or induced onset of labor, without previous cesarean section. Women delivering from 2009 to 2013 at Stavanger University Hospital, Norway, were included. Data were collected prospectively. Before implementing the protocol in 2010, oxytocin augmentation was used if progression of labor was perceived as slow. After implementation, oxytocin could only be started when the cervical dilation had crossed the 4-h action line in the partograph. RESULTS: The overall use of oxytocin augmentation was significantly reduced from 34.9% to 23.1% (p < 0.01). The overall frequency of emergency cesarean sections decreased from 6.9% to 5.3% (p < 0.05) and the frequency of emergency cesarean sections performed due to fetal distress was reduced from 3.2% to 2.0% (p = 0.01). The rate of women with duration of labor over 12 h increased from 4.4% to 8.5% (p < 0.01) and more women experienced severe estimated postpartum hemorrhage (2.6% vs. 3.7%; p = 0.01). The frequency of children with pH <7.1 in the umbilical artery was reduced from 4.7% to 3.2% (p < 0.01). CONCLUSIONS: The frequency of emergency cesarean section was reduced after implementing judicious use of oxytocin augmentation. Our findings may be of interest in the ongoing discussion of how the balanced use of oxytocin for labor augmentation can best be achieved.