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 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 35 mm were delivered by cesarean. Umbilical cord arterial pH 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

Occiput posterior position and intrapartum sonography

The occiput posterior position is reported to be the most common of all malpositions, and it may present as either straight (OP), left (LOP), or right (ROP). Diagnosis of OP position can be made at different times: during the third trimester, prior to the onset of labor, during the first stage of labor, while the fetus is transiting in the birth canal, and at birth. The time of diagnosis, though, is of different clinical significance, moving or not to a very specific management. Manual diagnosis of occiput posterior position either with abdominal palpation or vaginal examination is very subjective, prone to mistake, operator dependent, and made more difficult by caput and molding. Intrapartum ultrasonography has become a very reliable tool to hell the clinician to make a true diagnosis of malposition. The ultrasound probe may be used with different approach: transabdominal, suprapubical, transperineal, and transvaginal. The correct diagnosis of fetal head position as occiput posterior is imperative to be obtained in the management of any dystocia that may occur in the different stages of labor. Its knowledge will help the clinician to make the right decision at the right time, with the ultimate goal to reduce maternal and neonatal morbidity