Occiput Position Research Articles

Comparing intrapartum ultrasound and clinical examination in the assessment of fetal head position in African women.

IntroductionWe aimed to examine the agreement between intrapartum ultrasound and digital vaginal examination in assessing the occiput position in black African women who were in the first stage of labor and to evaluate the influence of ruptured membranes on this agreement.Material and methodThis was a cross-sectional study conducted in a teaching hospital in Ghana. Transabdominal ultrasound determination of the fetal head position was compared with digital vaginal examination of women in labor. The agreement between the two methods was examined with Cohen’s kappa statistics.ResultsAltogether, 196 women in active labor were studied. The fetal head position could not be determined by digital vaginal examination in 62 cases (32%) while ultrasound could determine all. Moderate agreement (kappa = 0.4) was obtained in the 134 cases determined by both methods. Agreement on the occiput posterior position was very low (kappa = 0.1). Agreement on the occiput posterior position was not significantly different in ruptured versus intact membranes.ConclusionThis study shows poor agreement between ultrasound and digital VE on the occiput posterior position in black African women who were in the first stage of labor. Again, over 85% of fetal head positions that could not be determined by digital vaginal examination were occiput transverse and posterior positions. This confirms that digital vaginal examination has difficulty in detecting malpositions, with no significant influence of intact or ruptured membranes. Ultrasound is therefore more useful than digital vaginal examination whenever malposition is suspected in the first stage of labor.

Antepartum ultrasound prediction of failed vacuum-assisted operative delivery: a prospective cohort study

Background Failed vacuum-assisted delivery (VD) is associated with increased risk of maternal perineal trauma and neonatal morbidity. Knowledge of the risk factors related to failed VD is essential in the clinical decision-making. Objective To elucidate the strength of association and the predictive accuracy of different ante-partum ultrasound parameters in predicting the risk of failed VD prior to the onset of Labor and to test the diagnostic performance of a multiparametric model including pregnancy and Labor characteristics, ante and intra-partum ultrasound in anticipating failed VD. Study design Prospective study of consecutive singleton pregnancies complicated by VD undergoing a dedicated ultrasound assessment at 36–38 weeks of gestation. Head circumference (HC), estimated fetal weight (EFW) and subpubic angle and (SPA) were recorded before the onset of Labor. At the time of the VD, occiput position, head perineum distance (HPD) and angle of progression (AOP) were also recorded. Multivariate logistic regression and area under the curve (AUC) analyses were used to explore the strength of association and test the diagnostic accuracy of different maternal, Labor and ultrasound characteristics in predicting g failed VD. Results Four hundred eight pregnancies with successful and 26 with failed VD were included in the analysis. Fetuses experiencing failed VD had a larger HC (1.21 versus 1.07 MoM; p = .0001), a higher EFW z-value (0.56 versus 0.33 z values; p = .002) and a narrower SPA (114 versus 122 p = .0001) compared to those having a successful VD. At multivariable logistic regression analysis, maternal height (aOR 0.89 95% CI 0.76–0.98), nulliparity (aOR: 1.14 95% CI 1.06–1.36), HC MoM (aOR: 1.24 95% CI 1.13–1.55) and SPA angle (aOR: 0.82 95% CI 0.67–0.95), but not EFW (p = .08) were independently associated with failed VD. When intrapartum ultrasound variables were added to the multivariate model, fetal occipital position (aOR: 1.45 95th CI 1.11–1.99) and HPD (aOR: 0.77 95th CI 0.44–0.96) were independently associated with failed VD. A multiparametric model integrating pregnancy and Labor characteristics and ante-partum ultrasound variables had an AUC of 0.837 (95% CI 0.797–0.876) for the prediction of failed VE. The addition of intra-partum ultrasound variables to the prediction model, improved the accuracy for failed VD provided by maternal and antepartum ultrasound characteristics with an AUC of 0.913 (0.888–0.937). Conclusion Antepartum prediction of failed VD is feasible. HC, SPA but not EFW are independently associated and predictive of failed VD. Adding these variables to a multiparametric model including maternal and intrapartum ultrasound parameters improves the diagnostic accuracy for failed VD.

EP27.35: A new ultrasound‐based Artificial intelligence system for the automatic identification of the fetal occiput position in labour

EP27.35: A new ultrasound‐based Artificial intelligence system for the automatic identification of the fetal occiput position in labour

Accuracy of the Manipal Cervical Scoring System for predicting successful induction of labour

The Manipal Cervical Scoring System is an accurate and objective sonographic score that predicts the outcome of induced labour. The aim of the current study was to compare the performance of the Manipal Cervical Scoring System against the Bishop Score. A prospective study was conducted on 105 women underwent labour induction in Ain Shams University Hospital, Cairo, Egypt. Both scores were assessed pre-induction. Successful induction occurred in 78.09% of the cases. The area under the ROC curve (AUC) was of 0.940 (95% CI = 0.876 to 0.977; p value <.0001) for the Manipal Score and 0.863 (95% CI = 0.783–0.923; p value <.0001) for the Bishop Score. The Manipal Score >5 had a sensitivity of 91.5% and a specificity of 91.3%. While the Bishop score >4 had a sensitivity of 98.8% and specificity of 69.6% to predict the outcome of induced labour. The Manipal Cervical Scoring system is a better objective tool to predict the outcome of labour induction compared to the Bishop Score. However, other female and fetal characteristics, including body mass index (BMI) at gestation, gestational weight gain, occiput position and parity should be taken into consideration when performing labour induction.Impact statementWhat is already known on this subject? The ultimate fate of 20% of women having an induction of labour (IOL) is a Caesarean delivery. Thus, predicting the possible response to IOL before starting induction could guide clinicians to determine the efficacy of starting and/or continuing the induction process and in counselling women regarding the possible response to IOL. The main predictor for IOL outcome is based on the pre-induction cervical status which has been traditionally assessed by the Bishop Score. However, the Bishop Score remains subjective, thereby, associated with high rates of bias and several studies have demonstrated its poor predictive value for the outcome of induction.What do the results of this study add? Proposed use of ultrasound parameters that are equivalent to Bishop Score will be objective, reliable and reproducible method. It allows for patient re-evaluation by other obstetricians without the need for re-examination (thus decreasing exposing the patient to pain and anxiety).What are the implications of these findings for clinical practice and/or further research? According to WHO and FIGO, oral misoprostol (25 μg, 2-hourly) is recommended for induction of labour. This helps to decrease the discomfort of repeated vaginal examination and increases the women satisfaction with labour process, especially in women at higher risk of infection. Thus evaluating cervical status using an ultrasound cervical scoring system can similarly increase women's satisfaction with labour process. Our goal in the upcoming trial is to perform RCT comparing ultrasound versus Bishop in women undergoing IOL using oral misopristol regarding measures of satisfaction during labour in the parturient women.

How reliable is fetal occiput and spine position assessment prior to induction of labor?

To assess the reliability of fetal occiput and spine position determination in nulliparous women prior to induction of labor (IOL), and to evaluate identification of fetal occiput and spine positions prior to IOL in the prediction of labor outcome. A series of 136 nulliparous women were recruited prospectively, immediately after the decision to perform IOL was made. Transabdominal ultrasound was performed to determine fetal head and spine positions. After at least 1 h, and prior to IOL, fetal occiput and spine positions were reassessed. Fetal occiput and spine positions were then compared between women who underwent vaginal delivery and those who delivered by Cesarean section. On the first and second assessments, respectively, fetal occiput position was anterior in 55 (40.4%) and 62 (45.6%) women, transverse in 52 (38.2%) and 49 (36.0%) women, and posterior in 29 (21.3%) and 25 (18.4%) women, while fetal spine position was anterior in 58 (42.6%) and 52 (38.2%) women, transverse in 42 (30.9%) and 50 (36.8%) women, and posterior in 36 (26.5%) and 34 (25.0%) women. Discordance between the first and second assessments of fetal occiput position was identified in 34 (25.0%) women, whereas discordance of fetal spine position was observed in 40 (29.4%) women. The incidence of fetal occiput posterior position in women undergoing Cesarean section was comparable to that in the vaginal-delivery group (19 (18.8%) vs 6 (17.1%); P = 0.826), which was similarly the case for fetal posterior spine position (27 (26.7%) vs 7 (20%); P = 0.428). Women with fetal occiput posterior position had a longer induction-to-delivery interval in comparison to those with non-occiput posterior fetal position (1786 ± 805 vs 1347 ± 784 min; P = 0.013). Fetal occiput and spine positions are dynamic in a considerable proportion of women undergoing IOL, and their assessment does not seem to correlate with mode of delivery. Occiput and spine position assessment in women prior to IOL is unlikely to be clinically useful. Copyright © 2018 ISUOG. Published by John Wiley & Sons Ltd.

Randomised Italian Sonography for occiput POSition Trial Ante vacuum (R.I.S.POS.T.A.).

To assess whether sonographic diagnosis of fetal head position before instrumental vaginal delivery can reduce the risk of failed vacuum extraction and improve delivery outcome. Randomised Italian Sonography for occiput POSition Trial Ante vacuum (R.I.S.POS.T.A.) is a randomized controlled trial of term (37 + 0 to 41 + 6 weeks' gestation) singleton pregnancies with cephalic presentation requiring instrumental delivery by vacuum extraction, which was conducted between April 2014 and June 2017 and involved 13 Italian maternity hospitals. Patients were randomized to assessment of fetal head position before attempted instrumental delivery by either vaginal examination (VE) alone or VE plus transabdominal sonography (TAS). Primary outcome was incidence of emergency Cesarean section due to failed vacuum extraction. A sample size of 653 women per group was planned to compare the primary outcome between the two groups. The sample size estimation was based on the hypothesis that the risk of failed vacuum delivery in the VE group would be 5% and that ultrasound assessment of fetal position prior to vacuum extraction would decrease this risk to 2%. On interim analysis, the trial was stopped for futility. During this period, 222 women were randomized and 221 were included in the final data analysis, of whom 132 (59.7%) were randomized to evaluation of fetal head position by VE only and 89 (40.3%) to assessment by VE plus TAS prior to vacuum extraction. No significant differences were observed between the two groups with respect to incidence of emergency Cesarean section due to failed instrumental delivery and other maternal and fetal outcomes. Women randomized to assessment by VE plus TAS showed higher incidence of non-occiput anterior position of the fetal head at randomization and lower incidence of incorrect diagnosis of occiput position compared with women undergoing assessment by VE alone. A higher rate of episiotomy was noted in the women undergoing both VE and TAS compared with those in the VE-only group. Our prematurely discontinued randomized controlled trial did not demonstrate any benefit in terms of reduced risk of failed instrumental delivery or maternal and fetal morbidity in women undergoing sonographic assessment of fetal head position prior to vacuum extraction. Copyright © 2018 ISUOG. Published by John Wiley & Sons Ltd.

P06.09: How reliable is fetal occiput and spine position assessment prior to induction of labour?

P06.09: How reliable is fetal occiput and spine position assessment prior to induction of labour?

Wednesday, September 26, 2018 7:35 AM–9:00 AM ePosters: P32. The most appropriate cervical vertebra for the measurement of occipitocervical inclination parameter: a validation study of C3, C4, and C5 using kinematic magnetic resonance imaging

BACKGROUND CONTEXT The occiput position in relation to the cervical spine is an important parameter when considering occipitocervical fusion procedure. The occipitocervical inclination (OCI) was introduced in order to measure the occiput position in relation to the subaxial cervical spine overcoming the anatomical variance of the axis and upper cervical spine anatomical distortion due to diseases or trauma. The most appropriate level of the subaxial cervical spine for measuring the OCI parameter is not well investigated. PURPOSE To evaluate which cervical level is the most appropriate level to measure occipitocervical inclination (OCI) parameter. STUDY DESIGN/SETTING Retrospective study. PATIENT SAMPLE A total of 62 cervical lordosis patients who underwent kinematic MRI (kMRI) and had disc degeneration grading of grade 3 or less. OUTCOME MEASURES The OCI at C3, C4, and C5, the ocipitocervical angle (OCA), the occipitocervical distance (OCD), C2-7 angle, and cervical sagittal vertical axis (cSVA) were measured. OCI is the angle formed by the line connecting the posterior border of the cervical vertebral body and McGregor's line. OCA is the angle formed by McRae's line and the line drawn parallel to the inferior endplate of C2. OCD is the shortest distance of the vertical line between occipital protuberance and the upper most part of spinous process of the axis. The C2-7 angle was measured as the angle between the tangent lines of the lower endplates of the axis and C7. cSVA is the horizontal distance between the center of C2 and the posterior edge of the C7 upper end plate. METHODS A total of 62 patients (38 females, mean age 43.3 years), who had cervical lordosis and grade 3 or less disc degeneration using kMRI were included in this study. The OCI at C3, C4, and C5, the OCA, the OCD, C2-7 angle, and cSVA were measured in flexion, neutral, and extension position. The correlation between each cervical level OCI and OCA, OCD, C2-7 angle, and cSVA in all three positions was tested using Pearson's correlation coefficient test. The difference between the OCI at each cervical level was tested using Wilcoxon-signed rank test. The p-value of less than .05 was set as the statistically significant level. RESULTS C5 OCI showed statistically significant correlation with OCA, OCD, C2-7 angle, and cSVA in all three positions (p CONCLUSIONS C5 cervical level is the most appropriate level for the measurement of OCI according to its significant correlation with the cervical spine sagittal parameters (C2-7 angle and cSVA) in all positions. In the case that the C5 OCI cannot be measured, the C4 OCI can reliably substitute C5 OCI because of their strong correlation coefficient.

The feasibility and accuracy of ultrasound assessment in the labor room

Objective: Vaginal examination is widely used to assess the progress of labor; however, it is subjective and poorly reproducible. We aim to assess the feasibility and accuracy of transabdominal and transperineal ultrasound compared to vaginal examination in the assessment of labor and its progress.Methods: Women were recruited as they presented for assessment of labor to a tertiary inner city maternity service. Paired vaginal and ultrasound assessments were performed in 192 women at 24–42 weeks. Fetal head position was assessed by transabdominal ultrasound defined in relation to the occiput position transformed to a 12-hour clock face; fetal head station defined as head-perineum distance by transperineal ultrasound; cervical dilatation by anterior to posterior cervical rim measurement and caput succedaneum by skin-skull distance on transperineal ultrasound.Results: Fetal head position was recorded in 99.7% (298/299) of US and 51.5% (154/299) on vaginal examination (p < .00011). Bland–Altman analysis showed 95% limits of agreement, −5.31 to 4.84 clock hours. Head station was recorded in 96.3% (308/320) on vaginal examination (VE) and 95.9% (307/320) on US (p = .791). Head station and head perineum distance were negatively correlated (Spearman’s r = −.57, p < .0001). 54.4% (178/327) of cervical dilatation measurements were determined using US and 100% on VE/speculum (p < .0001). Bland–Altman analysis showed 95% limits of agreement −2.51–2.16 cm. The presence of caput could be assessed in 98.4% (315/320) of US and was commented in 95.3% (305/320) of VEs, with agreement for the presence of caput of 76% (p < .05). Fetuses with caput greater than 10 mm had significantly lower head station (p < .0001).Conclusions: We describe comprehensive ultrasound assessments in the labor room that could be translated to the assessment of women in labor. Fetal head position is unreliably determined by vaginal examination and agrees poorly with US. Head perineum distance has a moderate correlation with fetal head station in relation to the ischial spines based on vaginal examination. Cervical dilatation is not reliably assessed by ultrasound except at dilatations of less than 4 cm. Caput is readily quantifiable by ultrasound and its presence is associated with lower fetal head station. Transabdominal and transperineal ultrasound is feasible in the labor room with an accuracy that is generally greater than vaginal examinations.

How Can Manual Rotation Reduce Vacuum, Forceps and Caesarean Deliveries?—A Review of the Evidence

The aim of this review was to investigate whether manual rotation can be used to reduce vacuum, forceps and caesarean deliveries in women with occiput posterior or occiput transverse positions from 7 cm dilation in labour. A search strategy was developed and relevant papers published between 1946 and January 2015 were identified from electronic databases. Key search terms used were manual and digital rotation, labour presentation, obstetric labour complications, occiput posterior and version foetal. The search revealed 330 papers. A short list of 33 publications of possible relevance was compiled and assessed using the following criteria: primary studies on the effectiveness of manual rotation performed in women with singleton occiput posterior or occiput transverse presentations published in English or the Scandinavian languages. The quality of the included studies was evaluated by means of the critical appraisal tools for quantitative studies. Seven studies were included in the thematic analysis. The results varied but the main finding was that in order to decrease vacuum, forceps and caesarean deliveries by means of manual rotation, it is essential that the procedure is successful. The success rate of manual rotation is dependent on the experience of the healthcare professionals who perform the rotation procedure rather than the technique employed. Predictors of successful manual rotation were used after engagement of the foetal head, at full dilatation and prophylactic use before failure to progress in labour. In conclusion, although the results vary, there is a consensus in all the studies that manual rotation is worth considering and that it can contribute to decreasing vacuum, forceps and caesarean deliveries. The implications for practice are that successful manual rotation can reduce caesarean delivery and increase spontaneous vaginal delivery, but experience is necessary to perform successful rotations. Because there are no risk factors associated with manual or digital rotation when performed after engagement of the head and at full dilatation, they are worth considering. The central role of the midwife in each individual labour makes her important for ensuring that manual rotation can be considered at the right time in labour.

P17.09: Diagnosis of fetal occiput position by transperineal sonography during the second stage of labour

P17.09: Diagnosis of fetal occiput position by transperineal sonography during the second stage of labour

Narrow subpubic arch angle is associated with higher risk of persistent occiput posterior position at delivery.

To determine whether the subpubic arch angle (SPA) measured by three-dimensional ultrasound is associated with the fetal occiput position at delivery and the mode of delivery. Nulliparous women with an uncomplicated singleton pregnancy at ≥ 37 weeks' gestation were recruited from two tertiary centers between September 2013 and August 2015. All women underwent a three-dimensional transperineal ultrasound examination and the SPA was measured using the previously validated Oblique View Extended Imaging software. Data on the outcome of labor were obtained prospectively in all cases and the correlations between SPA and the fetal occiput position at delivery and the incidence of operative delivery were investigated. Overall, 368 women were included in the study. Fetal position at delivery was occiput anterior in 339 (92.1%) cases and occiput posterior (OP) in 29 (7.9%) cases. A significantly narrower SPA was found in the OP group compared with the occiput anterior group (104.4 ± 16.8° vs 116.4 ± 11.9°; P < 0.0001). The SPA was significantly narrower in women requiring obstetric intervention compared with in women with a spontaneous vaginal delivery. From multivariable logistic regression analysis, SPA and maternal height appeared to be significant predictors of both the fetal occiput position at delivery and the risk of operative delivery. The best cut-off value of SPA for predicting an OP position at delivery was 90.5°. A narrow SPA is associated with a higher risk of persistent OP position at delivery and of operative delivery. Copyright © 2015 ISUOG. Published by John Wiley & Sons Ltd.

Sonographic assessment of fetal occiput position during labor for the prediction of labor dystocia and perinatal outcomes

Objectives: To evaluate the effect of the occiput posterior (OP) position on dystocia and perinatal outcomes. Methods: This was a prospective cohort study of 162 primiparous women. We performed intrapartum sonography, and fetal occiput positions were recorded. The relationships between the position of the occiput and the course of labor and perinatal outcomes were investigated. Statistical analysis was performed using SAS 9.2. Results: Fifty-six of 162 fetuses were found to be in the OP position during the first stage of labor. Eight (80.0%) of 10 fetuses in the OP position during the second stage were among the 56 that were in OP position during the first stage. The rate of cesarean sections performed in the OP position group during the first stage was significantly higher than the rate in the non-OP position group (37.5% versus 8.5%, p < 0.0001). The duration of the second stage of labor was longer and neonatal complications occurred more frequently in the OP position group during the second stage than in the non-OP position group (77.9 ± 33.4 min versus 52.2 ± 26.6 min, p = 0.0104; 50.0% versus 17.2%, p = 0.0118). Conclusions: The OP position may be a useful predicator for labor dystocia that can lead to poor neonatal outcomes.

Influence of ultrasound determination of fetal head position on mode of delivery: a pragmatic randomized trial.

To evaluate the influence of ultrasound determination of fetal head position on mode of delivery. This was a pragmatic open-label randomized controlled trial that included women with a singleton pregnancy in the vertex presentation at ≥ 37 weeks' gestation, cervical dilation ≥ 8 cm and who received epidural anesthesia. Women were assigned randomly to undergo either digital vaginal examination (VE group) or both digital vaginal and ultrasound examinations (VE+US group) to determine fetal head position. When the ultrasound and digital vaginal findings were inconsistent in the VE+US group, the ultrasound result was used for clinical management. The primary outcome assessed was operative delivery (Cesarean or instrumental vaginal delivery), and maternal and fetal morbidity were also assessed. The VE and VE+US groups included 959 and 944 women, respectively. The overall rate of operative delivery was significantly higher in the VE+US group than in the VE group: 33.7% vs 27.1%, respectively (relative risk (RR), 1.24 (95% CI, 1.08-1.43)), as was the rate of Cesarean delivery: 7.8% vs 4.9%, respectively (RR, 1.60 (95% CI, 1.12-2.28)). The rate of instrumental vaginal delivery was also higher, albeit not significantly: 25.8% in the VE+US group vs 22.2% in the VE group (RR, 1.16 (95% CI, 0.99-1.37)). Neonatal outcomes did not differ between the two groups. When analysis was restricted to instrumental vaginal deliveries only, maternal and neonatal morbidity outcomes were similar in both groups. Correction of fetal occiput position, determined initially by digital vaginal examination, using systematic ultrasound examination did not improve management of labor and increased the rate of operative delivery without decreasing maternal and neonatal morbidity.

EP01.12: A narrow subpubic arch angle is associated with a higher risk of persistent posterior occiput position

The aim of the present study was to determine whether the width of the subpubic arch angle (SPA) measured by 3D ultrasound (US) is associated with the fetal occiput position at delivery. A series of women with uncomplicated pregnancy were recruited at ≥37 weeks from 2 tertiary level centres. The SPA was measured by 3D transperineal US using the previously validated OVIX technique. Labour characteristics were investigated in all cases. Maternal and labour variables were then compared between the group with occiput anterior (OA) and persistent occiput posterior (OP) position at delivery. Overall, 369 women were included in the study group. Among these, fetal position at delivery was OA in 345 (93.5%) and OP in 24 (6.5%). In the OP group compared with the OA a narrower SPA (108.8 ± 15.8 vs. 117.2 ± 12.4, p = 0.002) was noted whereas all the other main variables including BMI, gestational age at delivery, epidural analgesia and birthweight were comparable. SPA had moderate predictive accuracy for persistent OP (area under the ROC curve 0.642, 95 C.I.% 0.514–0.770, P = 0.02). A narrow subpubic arch angle is associated with a higher risk of persistent posterior occiput position at birth.

Transverse occiput position: Using manual Rotation to aid Normal birth and improve delivery OUTcomes (TURN-OUT): A study protocol for a randomised controlled trial.

BackgroundFetal occiput transverse position in the form of deep transverse arrest has long been associated with caesarean section and instrumental vaginal delivery. Occiput transverse position incidentally found in the second stage of labour is also associated with operative delivery in high risk cohorts. There is evidence from cohort studies that prophylactic manual rotation reduces the caesarean section rate. This is a protocol for a double blind, multicentre, randomised, controlled clinical trial to define whether this intervention decreases the operative delivery (caesarean section, forceps or vacuum delivery) rate.Methods/DesignEligible participants will be ≥37 weeks pregnant, with a singleton pregnancy, and a cephalic presentation in the occiput transverse position on transabdominal ultrasound early in the second stage of labour. Based on a background risk of operative delivery of 49%, for a reduction to 35%, an alpha value of 0.05 and a beta value of 0.2, 416 participants will need to be enrolled. Participants will be randomised to either prophylactic manual rotation or a sham procedure. The primary outcome will be operative delivery. Secondary outcomes will be caesarean section, significant maternal mortality and morbidity, and significant perinatal mortality and morbidity.Analysis will be on an intention-to-treat basis. Primary and secondary outcomes will be compared using a chi-squared test. A logistic regression for the primary outcome will be undertaken to account for potential confounders. This study has been approved by the Ethics Review Committee (RPAH Zone) of the Sydney Local Health District, Sydney, Australia, (protocol number: X110410).DiscussionThis trial addresses an important clinical question concerning a commonly used procedure which has the potential to reduce operative delivery and its associated complications. Some issues discussed in the protocol include methods of assessing risk of bias due to inadequate masking of a procedural interventions, variations in intervention efficacy due to operator experience and the recruitment difficulties associated with intrapartum studies.Trial registrationThis trial was registered with the Australian New Zealand Clinical Trials Registry (identifier: ACTRN12613000005752) on 4 January 2013.

Effect of Lateral Tilt Angle on the Volume of the Abdominal Aorta and Inferior Vena Cava in Pregnant and Nonpregnant Women Determined by Magnetic Resonance Imaging

Assumed aortocaval compression (inferior vena cava [IVC] compression and compression of the abdominal aorta) by the gravid uterus in parturients in the supine position can cause hemodynamic disturbances and uteroplacental hypoperfusion. The left-lateral tilt position is used to reduce aortocaval compression, although this assumption has not been morphologically validated. Reported recommended angles, although controversial, are 15 degrees after spinal anesthesia for cesarean delivery, and 30 degrees is recommended during resuscitation in pregnant women. This study, using magnetic resonance imaging (MRI), aims to investigate whether the left-lateral tilt angle reduces aortocaval compression. Two groups of women, 10 healthy women at full term with cephalic singleton pregnancies and 10 nonpregnant healthy women, volunteered and gave written consent for the study. Magnetic resonance imaging scans were taken to measure the volume of the abdominal aorta and IVC from the L1-L2 disk level to the L3-L4 disk level at supine and 15-, 30-, and 45-degree positions. These angles were achieved by using a 1.5-long hard V block, running the length of the woman’s body. Mean arterial pressure, heart rate, and cardiac output were recorded in each position for each subject. Statistical significance was achieved when P < 0.05. The fetus was in the right occiput position in 7 of the group of 10 and in the left occiput position in 3. While the shape of the aorta in pregnant women was different in some MRI slices, there was no significance in the difference in aortic volume between groups in any position, nor was there significant difference in either group in any of the left-lateral tilt positions. In the supine position, IVC volume in pregnant women was significantly smaller than that in nonpregnant women (3.2 ± 3.4 vs 17.5 ± 7.8 mL; mean difference, 14.3 mL; P < 0.001). In pregnant women, IVC volume between the supine position and 15-degree left-tilt position was not significantly different (3.0 ± 2.1 mL; mean difference, −0.2 mL; P > 0.99), but IVC volume was significantly different between the supine position and 30-degree left-tilt position (11.5 ± 8.6 mL; mean difference, 8.3 mL; P = 0.009) and was also significantly between the supine position and 45 degrees (10.9 ± 6.8 mL; mean difference, 7.7 mL; P = 0.015). While tilt positions of 30 and 45 degrees partially relieved IVC compression compared with the supine position, a tilt position of 15 degrees did not. However, there are limitations of this study; for example, the pregnant and nonpregnant women did not receive anesthesia, and the parturients were not in labor. Future research should attempt to examine physiologic measures as well.

Étude préliminaire pour la réalisation d’un score échographique de prédiction d’accouchement par voie naturelle dans les 24 h après déclenchement du travail

ObjectiveEvaluate if a score based on ultrasound measurements (cervical length, perineal-fetal presentation distance, fetal occiput position) before the induction of labour is a good predictive test of vaginal delivery within 24h and compare it to Bishop score. MethodsFrom January to April 2014, we included in a monocentric prospective study 45 patients who underwent a labour induction in the department of obstetrics and gynecology at Croix-Rousse Hospital. Ultrasound measurements of the distance between the perineum and the foetal presentation (with transperineal ultrasound), of the cervical length (with transvaginal ultrasound) and of the position of the occiput were collected before induction. Bishop score was also calculated for these patients, without receiving ultrasound data (and vice versa), in order to determine the mode of induction. Receiver Operating Characteristics (ROC) curves were used to evaluate performance of the ultrasonographic score and the Bishop score for predicting vaginal delivery within 24h. ResultsThe area under the ROC curve for ultrasonographic score was 84.5% (IC95% 64,6–100%). The area under the ROC curve for Bishop score was 73.2% (IC95% 64,2–82,2%). The comparison of these areas under the curve has shown a difference of 11.3% with a P-value of 0.055 in a two-tailed test. ConclusionUltrasonographic score made with a combination of these ultrasound measurements appears to be an effective test to predict the chances of vaginal delivery within 24h of induction.

Sonographic assessment of fetal occiput position during the second stage of labor: how reliable is the transperineal approach?

Objective: To compare the accuracy of transperineal (TP) ultrasound with transabdominal (TA) approach in the sonographic assessment of fetal occiput position during the second stage of labour.Methods: A series of low-risk women at term attending the labour ward of three university hospitals were prospectively recruited for the purpose of this study. During the second stage of labor patients were evaluated first by TP and than by TA ultrasound to determine the fetal position. The occiput position was labelled as DOA (direct occiput anterior), ROA (right occiput anterior), LOA (left occiput anterior), DOP (direct occiput posterior), ROP (right occiput posterior), LOP (left occiput posterior), ROT (right occuput transverse) and LOT (left occiput transverse). The agreement between the two techniques was assessed.Results: Overall 80 patients were recruited in the study group. Ultrasound examination was performed at 21(±8) minutes from the beginning of the active pushing. The ultrasound findings of the fetal occiput position were recorded. In all cases TA ultrasound confirmed the fetal occiput position as determined at TP approach except in one case of ROA that had been recorded as ROT using TP ultrasound.Conclusions: Ultrasound TP examination is accurate in the diagnosis of fetal occiput position during the second stage of labor.

Sonographic pattern of fetal head descent: relationship with duration of active second stage of labor and occiput position at delivery

The objectives of this study were firstly to assess the longitudinal changes of various sonographic parameters of fetal head progression in relation to length of active second stage of labor, and secondly to compare ultrasound findings obtained longitudinally among fetuses with persistent occiput posterior (OP) vs those with persistent occiput anterior (OA) position. From a series of nulliparous low-risk women at term attending the labor ward of our university hospital, transperineal ultrasound volumes were prospectively acquired at the beginning of the active second stage (T1) and at 40-min intervals thereafter until delivery (T2, T3). Sonographic parameters were derived from offline analysis of each volume, including the angle of progression (AoP), progression distance (PD), head-symphysis distance (HSD), head direction (HD) and midline angle. These parameters were compared between patients who delivered within 60 min from the beginning of the active second stage of labor (early delivery) and those who remained undelivered by that time (late delivery). Fetal head position was determined from stored digital images of transabdominal examinations performed at the beginning of the active second stage. Comparison was performed between fetuses with OA and those with persistent OP position at delivery. Spontaneous vaginal delivery was achieved in 58 (81.7%) cases, whereas vacuum extraction and Cesarean section were performed in eight (11.3%) and five (7.0%) cases, respectively. Delivery was achieved within 60 min from the beginning of the active second stage in 44 (62.0%) patients. In the early vs late delivery groups, measurements of AoP, HSD and PD at T1 were significantly different (AoP, 143.9 ± 20.5° vs 125.3 ± 15.0°, P < 0.001; HSD, 14.8 ± 4.5 mm vs 20.9 ± 5.8 mm, P < 0.001; PD, 44.0 ± 14.1 vs 35.0 ± 13.1 mm, P = 0.008). On logistic regression analysis of data obtained at T1, maternal body mass index, oxytocin administration, neonatal birth weight and HSD appeared to predict independently duration of the active second stage. Among fetuses delivering in the OP position (n = 10, 13.5%), Cesarean delivery was significantly more common than in those delivering in the OA position (n = 5 (50.0%) vs n = 2 (3.1%), P = 0.001). Women with persistent OP position compared with OA showed a significantly different AoP at T1 (122 ± 17° vs 138 ± 20°, P = 0.016), HD and HSD at T1 (HD, 112 ± 17 mm vs 86 ± 19 mm, P < 0.001; HSD, 16.5 ± 5.4 mm vs 22.8 ± 6.6 mm, P = 0.008) and at T2 (HD, 120 ± 16 vs 82 ± 27 mm, P = 0.008; HSD, 12.6 ± 3.4 mm vs 18.5 ± 5.4 mm, P = 0.038). AoP, PD and HSD are significantly different between patients undergoing delivery before or after 60 min from the beginning of the active second stage of labor. Ultrasound parameters are among the significant predictors of duration of the active second stage. Moreover, in fetuses persisting in the OP position vs those delivering in the OA position, fetal head progression seems to differ at early phases of the active second stage.