Head Station Research Articles

OP26.07: Fetal head station and angle of progression during second stage of labour: correlation and normal reference range

OP26.07: Fetal head station and angle of progression during second stage of labour: correlation and normal reference range

Maternal and Neonatal Morbidity After Attempted Operative Vaginal Delivery According to Fetal Head Station

(Obstet Gynecol. 2015;126:521–529) It has been suggested that midpelvic operative vaginal delivery methods (eg, vacuum extraction, Thierry’s spatulas, or forceps) might significantly increase maternal and neonatal morbidity. However, the data are not up-to-date. Subsequently, the authors of the present study assessed severe maternal and neonatal morbidity after attempted operative vaginal delivery and also compared morbidity after midpelvic and low pelvic delivery attempts.

Perinatal outcomes of vacuum assisted versus cesarean deliveries for prolonged second stage of delivery at term*

Introduction: To compare perinatal outcomes of interventions for prolonged second stage of labor. Materials and methods: Retrospective cohort study, in a single, university-affiliate, medical center (2007–2014). Eligibility: singleton gestations at term, diagnosed with prolonged second stage of labor and head station of S + 1 and lower. We compared perinatal outcomes of cesarean deliveries (CD) with vacuum assisted deliveries (VAD). Results: Of 62 102 deliveries, 3449 (5.6%) were eligible: 356 (10.3%) underwent CD and 3093 (89.7%) underwent VAD. The rate of five-minute Apgar scores <7 was higher in the CD group as well as rates of NICU admission, neonatal asphyxia and composite neonatal adverse outcome. After adjusting for different confounders, CD was associated with adverse neonatal composite outcome (aOR 1.57, 95% CI 1.21–2.05, p = 0.001) and VAD with cephalhematoma (aOR 4.06, 95% CI 2.64–6.25, p < 0.001). No other differences were found between the groups with regards to other traumatic outcomes. Conclusion: Our data suggests that in deliveries complicated by prolonged second stage, CD yield poorer neonatal outcome than VAD, with no apparent major difference in traumatic composite outcome.

Correlation of intrapartum translabial ultrasound parameters with computed tomographic 3D reconstruction of the female pelvis.

Intrapartum translabial ultrasound [ITU] can be an objective, reproducible and more reliable method than digital vaginal examination when evaluating fetal head position and station in prolonged second stage of labor. However, two-dimensional (2D) ultrasound is not sufficient to demonstrate the ischial spines and other important "landmarks" of the female pelvis. Therefore, the purpose of this study was to evaluate the distance of the interspinous plane as a parallel line to the infrapubic line in 2D ITU with the help of 3D computed tomography and digital reconstruction. Mean distance between the infrapubic plane and the tip of the ischiadic spine was 32.35 (±4.46) mm. The mean height was 166 (±7) cm; the mean weight was 67.5 (±18.4) kg. Body height and the measured distance were significantly correlated (P=0.025; correlation coefficient of 0.5), whereas body weight was not (P=0.37; correlation coefficient of -0.214). With the present results, clinicians were enabled to transfer the reproducible measurements of the "head station" by ITU to the widespread but observer-depending vaginal examination. Furthermore, ITU can be verified as an objective method in comparison to subjective palpation with the ability to optimize the evaluation of the head station according to bony structures as landmarks in a standardized application.

The Design and Engineering of the 187 km Khouribga to Jorf Lasfar Phosphate Slurry Pipeline

The Jorf Lasfar phosphate slurry pipeline in Morocco, commissioned in April 2014, is one of the world's largest slurry pipelines. The pipeline receives phosphate ore from the El Halassa, MEA and Daoui wash plants situated up to 22km away. The product from these plants varies in grade and quality and is stored in separate agitated slurry tanks at the Khouribga head station. From the head station the slurry is pumped 187km in batches separated by water to the terminal station at Jorf Lasfar. As these batches of phosphate slurry arrive at the terminal station they are diverted to dedicated storage tanks that feed separate process streams in the refinery. This means that the pipeline design needs to accommodate the slurry transport requirements of the different batches and to be able identify where these batches are during transport so as to ensure they are allocated to the appropriate tanks. As the batches are intermittent and have variable flow properties the design needs to accommodate a wide range of operating conditions. This is achieved by controlling the pipeline operation by varying the pumping head and through a series of pressure monitoring stations and a choke station at the terminal. Due to the scale of the project the system comprises some of the largest slurry handling equipment yet produced and this presented many unique challenges for the engineering team that required an innovative approach to solving such unique problems. This paper presents a few of the design and engineering challenges faced by the engineering team responsible for successfully delivering this project.

832: Pelvic floor disorders 6 months after attempted operative vaginal delivery according to the fetal head station

832: Pelvic floor disorders 6 months after attempted operative vaginal delivery according to the fetal head station

Anterior rotation in occiput transverse and occiput posterior positions

Objective To investigate the natural rotation of the fetal head during labor when it was engaged by occiput transverse (OT) or occiput posterior(OP) positions. Methods A total of 1 013 parturients was included who had a singleton term gestation, vertex presentation, OT or OP position with cervical dilatation of ≤ 3 cm, and vaginal delivery. All parturients were delivered in Xiamen Hospital of Traditional Chinese Medicine during April 1 to December 31, 2014. Cervical dilation, station, and fetal position of every delivery were systematically recorded. Main outcome was the cervical dilation and station of anterior rotation from OT or OP position. They were Stratified by cervical dilation every 2 cm since 4 cm into 4~5 cm, 6~7 cm, 8~9 cm, 10 cm; or were stratified by fetal head station every 1 cm since -2 (S-2) into S-1, S0, S+ 1, S+ 2, S+ 3. The differences in anterior rotation rate, dilatation, and head station between OT and OP were analyzed. Results There were 850 OT and 407 OP with cervical dilatation of ≤3 cm. The rate of anterior rotation was 82.5% (701/850) and 76.7% (312/407), respectively. The constituent ratio of OT rotating into occiput anterior position (OA) at different dilatation was different with that of OP (χ2=260.93, P<0.01) . The constituent ratio of OT rotating into OA at different fetal head station was different with that of OP (χ2=133.18, P<0.01). The cervical dilatation and fetal head station that make it easy for OT 's anterior rotation were 6~7 cm (OR=5.81 , 95% CI: 3.81~8.87), 8~9 cm(OR=4.99 , 95% CI: 3.19~7.83), and S+ 1(OR=3.01, 95% CI: 1.99~4.54), S+ 2(OR=5.43, 95% CI: 3.53~8.35). The cervical dilatation and fetal head station that make it easy for OP 's anterior rotation were 6~7 cm(OR=4.11, 95% CI: 2.24~7.89), 8~9 cm(OR=27.31, 95% CI: 15.12~49.34), 10 cm(OR=27.76 , 95% CI: 14.87~51.82), S+ 2(OR=4.84 , 95% CI: 3.03~7.73). Conclusions The anterior rotation time of OT is different from OP . It's easy for OT to rotate into OA when cervix dilate into 6~9 cm and fetal head station is at S+ 1~S+ 2. When cervix dilate into 6~10 cm and fetal head station is at S+ 2, it's easy for OP to rotate into OA. Key words: Labor, obstetric; ABNORMAL FETAL POSITIONS; Version, fetal

Prospective multicenter study of ultrasound-based measurements of fetal head station and position throughout labor.

To assess the relationship between fetal head position and head station during labor, as measured using an ultrasound-based system, and the occurrence of occiput posterior (OP) position at delivery. This was an international prospective observational study including women who delivered between January 2009 and September 2013 in four centers: one in Brooklyn, NY, USA; one in Haifa, Israel; and two in Paris, France. We used an ultrasound-based system (LaborPro) to monitor fetal head station and position non-invasively throughout labor. We collected data on demographics, labor parameters and outcome. A total of 595 women were included. In 563 (94.6%) women, fetal head position at delivery was occiput anterior (OA), in 31 (5.2%) it was OP and in one (0.2%) it was occiput transverse. In 89% of pregnancies with intrapartum OP when fetal head station was above -2, the head position turned to OA at delivery; the equivalent figures were 74% and 63% OA at delivery when intrapartum OP was diagnosed at head stations of -2 to < 0, and 0 and below, respectively. Cesarean delivery was performed in 35% of pregnancies with fetal head in OP position at delivery, as opposed to 10% of those with non-OP position at delivery. On retrospective analysis, all deliveries in OP were already in OP at station -2 and below. In this first assessment of fetal head position at delivery according to fetal head position at various station levels, our data show that 100% of OP positions at delivery were already in OP position at station -2 and below. We did not observe rotation from a non-OP to an OP position from station -2 and below. Nearly two-thirds of fetuses in OP at station 0 and below will rotate to an OA position for delivery.

Maternal and Neonatal Morbidity After Attempted Operative Vaginal Delivery According to Fetal Head Station.

To compare severe short-term maternal and neonatal morbidity associated with midpelvic and low pelvic attempted operative vaginal delivery. Prospective study of 2,138 women with live singleton term fetuses in vertex presentation who underwent an attempted operative vaginal delivery in a tertiary care university hospital. We used multivariate logistic regression and propensity score methods to compare outcomes associated with midpelvic and low pelvic delivery. Severe maternal morbidity was defined as third- or fourth-degree perineal laceration, perineal hematoma, cervical laceration, extended uterine incision for cesarean delivery, postpartum hemorrhage greater than 1,500 mL, surgical hemostatic procedures, uterine artery embolization, blood transfusion, infection, thromboembolic events, admission to the intensive care unit, and maternal death; severe neonatal morbidity was defined as 5-minute Apgar score less than 7, umbilical artery pH less than 7.00, need for resuscitation or intubation, neonatal trauma, intraventricular hemorrhage greater than grade 2, neonatal intensive care unit admission for more than 24 hours, convulsions, sepsis, and neonatal death. From December 2008 through October 2013 there were 2,138 attempted operative vaginal deliveries; 18.3% (n=391) were midpelvic, 72.5% (n=1,550) low, and 9.2% (n=197) outlet. Severe maternal morbidity occurred in 10.2% (n=40) of midpelvic, 7.8% (n=121) of low, and 6.6% (n=13) of outlet attempts (P=.21); and severe neonatal morbidity in 15.1% (n=59), 10.2% (n=158), and 10.7% (n=21) (P=.02), respectively. Multivariable logistic regression analysis found no significant difference between midpelvic and low attempted operative vaginal delivery for either composite severe maternal (adjusted odds ratio [OR] 1.01, 95% confidence interval [CI] 0.66-1.55) or neonatal morbidity (adjusted OR 1.25, 95% CI 0.84-1.86). Similarly, propensity score matching found no significant difference between midpelvic and low operative vaginal delivery for either severe maternal (adjusted OR 0.69, 95% CI 0.39-1.22) or neonatal morbidity (adjusted OR 0.88, 95% CI 0.53-1.45). In singleton term pregnancies, midpelvic attempted operative vaginal delivery compared with low pelvic attempted operative vaginal delivery was not associated with an increase in severe short-term maternal or neonatal morbidity. II.

EP01.02: Correlation between the sonographic measurement of the occiput spine angle and the fetal head station in the 1st stage of labour

EP01.02: Correlation between the sonographic measurement of the occiput spine angle and the fetal head station in the 1st stage of labour

Transperineal ultrasonography for labor management: accuracy and reliability

To compare ultrasound measurements and clinical assessments of cervical dilatation, fetal head station and fetal head position. Prospective, observational study. Tertiary care center (Ankara University Hospital), labor ward. Forty-three women in labor. Women were prospectively evaluated through simultaneous examinations (79 in total). Dilatation, head station, and position were recorded via digital examination whenever possible and were compared with ultrasonographic measurements of dilatation, angle of progression, head-perineum distance, and head position by two independent operators. Operators were blinded to each other's findings. Agreement between sonographic measurements and digital examinations. Ultrasonographic assessment of dilatation correlated significantly with digital examination. The interclass correlation coefficient of the two methods was 0.82 (95% confidence interval 0.73-0.88). Ultrasonography showed a mean lower cervical dilatation of 10 mm (95% limits of agreement: -36 to 16 mm) compared with digital examination. The angle of progression and head-perineum distances correlated moderately with the palpated head station (Pearson's correlation coefficients: 0.55 and -0.42, respectively; p < 0.001). Position could only be assessed in 40 of 79 examinations by digital examinations and the results showed low agreement with ultrasound findings. We observed good agreement between clinical and ultrasound assessment of dilatation, moderate agreement in assessing fetal station and low agreement assessing head position.

Can Ultrasound Performed in Prolonged Second Stage of Labor Predict the Difficulty and Success Rates of Operative Vaginal Delivery?

To evaluate different sonographic methods for the prediction of the difficulty and the success of operative vaginal delivery (OPD). A prospective study was performed on 45 term singleton uncomplicated pregnancies with prolonged 2nd stage of delivery with cephalic presentation. Measurements of the fetal head, relations between the fetal head and maternal pelvic parameters during rest and during maternal pushing were taken using translabial ultrasound. 29 cases of OPD were successful and 4 cases failed ending in cesarean section. The passage of the biparietal diameter (BPD) of the infrapubic line (IPL) was statistically correlated with the success of OPD. Head station, passage of the BPD of the IPL, percentage of head after the IPL, circumference of head after IPL were all correlated with the difficulty of OPD. When the distance between the widest diameter of the head and the IPL is < 1.2 cm, there is a 90 % probability of success of OPD. When that distance is > 3.3 cm, there is 90 % probability of cesarean section. When the percentage of head beyond the IPL was > 54 %, there was 90 % probability of successful OPD. Translabial ultrasound is useful in the prediction of the difficulty and the success of OPD. The higher the extent of head that passed the IPL, the less difficult the OPD and the greater the success rate of the OPD.

Risk factors for anal sphincter tears in vacuum-assisted delivery

ObjectiveThe aim of the present study was to describe the prevalence of anal sphincter tears (AST) in relation to obstetric management and technique during vacuum extraction deliveries (VE) (re: indications, the station of the fetal head at application of the cup, number of tractions, the length for the extraction, cup detachments, pain relief, episiotomy, fetal presentation, and experience of the operator) as well as maternal and infant anthropometrics. MethodsDescriptive study. Data on six hundred vacuum extraction deliveries were consecutively collected from six different delivery units in Sweden. Each unit contributed with data on 100 deliveries. The final study population included 596 women who delivered by vacuum extraction. ResultsThere was no correlation between the management of the vacuum extraction and risk for anal sphincter tear. Women from Africa had nearly a fourfold risk for anal sphincter tear during vacuum-assisted delivery compared with Swedish-born women (OR 3.82 CI 1.47–9.89). Compared with infants with birth weight less than 4000 g, birth weight above 4000 g was associated with increased risk of AST (OR 1.87 CI 1.06–3.28). ConclusionsIn this study, the obstetric management in VE-assisted deliveries did not impact the risk of AST.

Clustering Routing Algorithm for Heterogeneous WSN with Energy Harvesting

Focus on the character of energy harvesting sensor network in heterogeneous sensor network and some shortage in SEP algorithm, an improved algorithm for EH-SEP is been proposed. EH-SEP considers both residual energy and energy support of nodes in cluster-head election process .Improved algorithm achieves higher probability that the advanced nodes with high residual energy to be cluster-head, and lower probability that the traditional nodes with low residual energy to be cluster-head. During the state of data sensing, this paper adopted multiple hop data transmission to avoid long distance communication between the cluster head and base station, so it can improve the network energy utilization. The simulation result shows that: EH-SEP algorithm is not only suitable for energy harvesting of wireless sensor network, but also effectively prolong the work time in the network stable stage.

A Key Management Technique to Secure Information Sharing of the Nodes within a Cluster of WSN

The nodes within a cluster of Wireless Sensor Network deployed in adverse areas face the security threats of eavesdropping and capturing. The fundamental issue in wireless sensor network security is to initialize secure communication between sensor nodes by setting up secret keys between communicating nodes. Because of limited hardware capacity, conventional network cryptography is infeasible for sensor network. In this paper a key management technique is proposed for clustered sensor network that uses some cryptographic operation to generate secret keys. This key is updated in response to the message of cluster head or base station. The key update instructions are stored in each sensor nodes before deployed in sensor field. The updated secret key is used to communicate between nodes and cluster head.

19: Optimizing second stage outcomes: a randomized controled trial assessing the ability of precise maternal feedback to reduce adverse perinatal outcomes

19 Optimizing second stage outcomes: a randomized controled trial assessing the ability of precise maternal feedback to reduce adverse perinatal outcomes Merlin Fausett, P. Barrilleaux, Jonnie Buford Women’s and Childrens Hospital, OB/GYN, Lafayette, LA, Community Medical Center, OB/GYN, Missoula, MT OBJECTIVE: Regional anesthesia reduces biofeedback impeding pushing efficacy during second stage labor. Long second stage is associated with adverse outcomes. We assessed the clinical impact of providing laboring women real-time audiovisual feedback regarding fetal descent during second stage. STUDY DESIGN: Abiofeedback device detecting fetal decentwas attached to 69 primigravidas receiving epidural anesthesia. Fetal decent was measured & conveyed at sub-second and sub-millimeter intervals. After attachment of the feedback device, women were randomized 2:1 to Feedback (Study) and No Feedback (Control) groups. The 45 women in the Study groupwere provided audiovisual feedback. Second stage management was otherwise routine in both groups. The primary outcome of interest was length of second stage (LSS). Secondarily, we assessed individual adverse outcomes (AO) rates for operative vaginal delivery (OVD), cesarean delivery (CS), 3rd/4th degree laceration (LAC), intra-amniotic infection (IAI), perineal edema (E) and NICU admissions. Length of second stage regression models controlled for initial head station (HS) and birth weight (BW). RESULTS: For women delivering vaginally, the median pushing time was 58 vs. 77 minutes for Study and Control groups respectively. The lower 3 quartiles of the Study group had a 23 minute (26%) reduction in LSS (p1⁄40.016), see Figure 1. The AO rates of OVD, LAC, IAI, and E were all lower in the Study group (all p values < 0.02). The CS rate was not different but the composite AO rate was 73% lower in the Study group (p 1⁄4 0.011)-Table 1. Women with any AO, had a mean 2 hour increased hospital length of stay, p<0.01. CONCLUSION: A system providing precise measurement of fetal decent and maternal feedback during second stage labor substantially shortens second stage. In nulliparous women with epidural anesthesia, this feedback system decreases key individual and composite adverse maternal outcomes and decreases NICU admissions.

Maternal and obstetrical factors associated with a successful trial of vaginal birth after cesarean section.

To detect the maternal and obstetrical factors associated with successful trial of vaginal birth among women with a previous cesarean delivery. A total of 122 women who were eligible for a trial of labor after cesarean section (TOLAC) according to departmental protocol were included in this comparative prospective study. After informed consent, the women included in this study were subjected to a thorough history to detect maternal and obstetric characteristics and a standard examination to estimate fetal weight, engagement of the fetal head, intra-partum features of fetal membranes, and cervical dilatation. After delivery, data on duration of labor, labor augmentation, mode of delivery, birth outcome, and neonatal intensive care (NICU) admission were recorded and analyzed. Trial of labor after cesarean section was successful in 72.13% and was unsuccessful in 27.87%. Body mass index (BMI) was significantly lower in the successful TOLAC group compared to the unsuccessful group (23.8±0.03 versus 26.2±0.02 kg/m(2)), and the number of women with BMI >25 kg/m(2) was significantly high in the unsuccessful group; also, mean gestational age was significantly lower in the successful TOLAC group compared to the unsuccessful group (37.5±0.04 versus 38.5±0.03 weeks), and the number of women admitted in labor with gestation ≥40 weeks was significantly high in the unsuccessful group. The number of women admitted with >2/5 of fetal head palpable abdominally and fetal head station ≥-2 was significantly high in the unsuccessful TOLAC group. In carefully selected cases, TOLAC is safe and often successful. Presence of BMI >25 kg/m(2), gestation ≥40 weeks, and vertex station ≥-2 were risk factors for unsuccessful TOLAC.

Relationship between intrapartum transperineal ultrasound measurement of angle of progression and head–perineum distance with correlation to conventional clinical parameters of labor progress and time to delivery

Objective: To assess whether angle of progression (AOP) and head–perineum distance (HPD) measured by intrapartum transperineal ultrasound (ITU) correlate with clinical fetal head station (station); and whether AOP versus HPD varies during uterine contraction and relaxation. In a subset of primipaorus women, whether these ITU parameters correlate with time to normal spontaneous delivery (TD). Methods: We evaluated prospectively 100 primiparous and multiparous women at term in active labor. Transabdominal and transperineal ultrasound (sagittal and transverse plane) were used to measure fetal head position and ITU parameters, respectively. Digitally palpated station and cervical dilatation were also noted. The results were compared using regression and correlation coefficients. Results: Station was moderately correlated with AOP (r = 0.579) and HPD (r = −0.497). AOP was highly correlated with HPD during uterine contraction (r = −0.703) and relaxation (r = −0.647). In the subgroup of primiparous women, natural log of TD has the highest correlation with HPD and AOP during uterine contraction (r = 0.742), making prediction of TD similar to that of using cervical dilatation. Conclusion: ITU parameters were moderately correlated with station. There was constant high correlation between AOP and HPD. Prediction of TD in primiparous women using ITU parameters was similar to that of using cervical dilatation.

Usability Study of the EduMod eLearning Program: Head and Neck Nodal Station Contouring

Usability Study of the EduMod eLearning Program: Head and Neck Nodal Station Contouring

Intrapartum ultrasound prior to Kristeller maneuver: an observational study.

To evaluate the accuracy of criteria followed by obstetricians when performing a Kristeller maneuver in cases of prolonged second stage of labor. In this prospective observational study, the station of the fetal head was measured using the angle of progression (intrapartum ultrasound) just prior to the intervention of the managing obstetrician in 52 women with prolonged second stage of labor. The managing obstetricians were blinded to the sonographic results. The decision of performing a Kristeller maneuver was taken by the obstetricians based on digital palpation and their experience. Delivery mode, Apgar score, umbilical artery pH value, episiotomy, perineal tears, bleeding, and time to delivery were recorded. Kristeller maneuver was performed in 36/52 (69.2%) cases. There were no significant differences between the Kristeller and the non-Kristeller group regarding the angle of progression. There were no significant differences between both groups with respect to delivery mode, perineal tears, episiotomy, bleeding, Apgar score, and umbilical artery pH value. Our study failed to define any criteria followed by obstetricians when performing a Kristeller maneuver in cases of prolonged second stage of labor. There was no relation between the angle of progression and the decision to perform a Kristeller maneuver.