Shock management in acute fetomaternal hemorrhage

Abstract

The determination of fetal head position can be useful in labor to predict the success of labor management, especially in case of malpositions. Malpositions are abnormal positions of the vertex of the fetal head and account for the large part of indication for cesarean sections for dystocic labor. The occiput posterior position occurs in 15–25% of patients before labor at term and, however, most occiput posterior presentations rotate during labor, so that the incidence of occiput posterior at vaginal birth is approximately 5–7%. Persistence of the occiput posterior position is associated with higher rate of interventions and with maternal and neonatal complications and the knowledge of the exact position of the fetal head is of paramount importance prior to any operative vaginal delivery, for both the safe positioning of the instrument that may be used (i.e. forceps versus vacuum) and for its successful outcome. Ultrasound (US) diagnosed occiput posterior position during labor can predict occiput posterior position at birth. By these evidences, the time requested for fetal head descent and the position in the birth canal, had an impact on the diagnosis of labor progression or arrested labor. To try to reduce this pitfalls, authors developed a new algorithm, applied to intrapartum US and based on suitable US pictures, that sets out, in detail, the quantitative evaluation, in degrees, of the occiput posterior position of the fetal head in the pelvis and the birth canal, respectively, in the first and second stage of labor. Authors tested this computer system in a settle of patients in labor.     

Clinical and sonographic diagnosis of occiput posterior position: a prospective study of 350 deliveries

OBJECTIVE: To evaluate clinical reliability compared to intrapartum ultrasound as a tool to diagnose occiput posterior position and to investigate the proportion of rotations occurring during labour. PATIENTS AND METHODS: 350 women in labor with a singleton fetus in a vertex position were prospectively studied using ultrasound and obstetrical examination. Outcome of labor was also monitored. RESULTS: Reliability of clinical examination is 85,7%, initial occiput posterior position represented 40,2% and most rotated in an anterior position (84, 8%) while only 0,6% of initial anterior positions delivered in occiput posterior position. Logistic regression did not allow to find significant predictor of occiput posterior position rotation. DISCUSSION AND CONCLUSION: Clinical examination is relatively reliable for posterior position diagnosis and in most cases, initially occipitoposterior positions rotate anteriorly.     

Diagnosis and intervention for occiput posterior malposition

OBJECTIVES: To evaluate diagnostic methods used to detect occiput posterior and to describe the efficacy of posturing to enhance rotation from occiput posterior to occiput anterior. DATA SOURCES: Keyword search using PubMed, CINAHL, Cochrane Review, and Dissertation Abstracts International. STUDY SELECTION: Studies published from 1996 to 2006 (except one published in 1983) that focused on the use of ultrasonography versus digital vaginal examination to diagnose fetal position and maternal posturing to enhance rotation from occiput posterior to occiput anterior. DATA EXTRACTION: Eight prospective studies regarding malposition diagnosis were reviewed and analyzed for error rates and predictors affecting ability to detect fetal position; five randomized controlled trials were evaluated for effects of various maternal postures on fetal rotation from occiput posterior to occiput anterior. DATA SYNTHESIS: If fetal malposition is accurately diagnosed in early labor, subsequent nursing management can focus on rotation toward occiput anterior position, leading to a safer delivery for mother and baby. CONCLUSIONS: Antepartum ultrasonography is more accurate than digital vaginal examination in diagnosing fetal malposition; however, its efficacy needs to be further explored using randomized controlled trials and cost-benefit analyses before routine use is recommended. Furthermore, Sims' posture on the same side as the fetal spine is recommended during labor to enhance rotation from occiput posterior to occiput anterior.     

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.     

持续性枕后位的临床特点及分娩方式选择

目的探讨持续性枕后位的临床特点及分娩方式。方法采用回顾性分析方法，对1998年1月至2004年12月在重庆医科大学两所附属医院住院分娩的112例持续性枕后位（枕后位组）和112例枕前位（枕前位组）的临床资料进行分析，比较两组产程情况、分娩方式及母儿结局。结果两组头位分娩评分、第一产程、第二产程及总产程时间比较，差异有显著性意义（P〈0．05）。枕后位组产钳助产、剖宫产、会阴裂伤、产后出血、胎儿窘迫、新生儿窒息率等均明显高于枕前位组，差异均有显著性意义（P〈0．05）。枕后位组宫口扩张及胎头下降延缓和第二产程延长的发生率均高于枕前位组，差异均有显著性意义（P〈0．05）。剖宫产组富口扩张延缓、胎头下降停滞和第二产程延长的发生率明显高于阴道分娩组（P〈0．05）。而剖宫产组和阴道分娩组骨盆临界狭窄、潜伏期及活跃期延长的发生率比较，差异无显著性意义（P〉0．05）。结论持续性枕后位导致母儿并发症增加，及时处理并选择最佳分娩方式可减少母儿并发症的发生。     

Maternal Temperature Elevation and Occiput Posterior Position at Birth Among Low‐Risk Women Receiving Epidural Analgesia

Introduction: To evaluate the relationship between maternal temperature elevation and occiput posterior position at birth as well as the association of fetal head position and temperature elevation on method of birth among women receiving epidural analgesia. Methods: We conducted a secondary analysis of data from the Fetal Orientation during Childbirth by Ultrasound Study (FOCUS), which used serial ultrasounds to evaluate the effect of epidural anesthesia on fetal position at birth in low‐risk women. The current analysis was limited to the 1428 study participants who received epidural analgesia. Results: In our population, 47% (n = 669) of women had a maximum intrapartum temperature greater than or equal to 99.6°F (37.6°C). The prevalence of fetal occiput posterior position at admission did not differ between women who later developed temperature elevations (24.4%) and those who did not (23.6%, P= .70). Women who developed an elevated temperature greater than or equal to 99.6°F (37.6°C) had an increased risk of occiput posterior fetal head position at birth regardless of the amount of temperature elevation (odds ratio [OR]= 2.0; 95% confidence interval [CI], 1.5‐2.8); the association persisted after control for potentially confounding factors (adjusted OR = 1.5; 95% CI, 1.1‐2.1). The cesarean birth rate among women with both temperature elevation and occiput posterior position at birth was more than 12 times the rate of women with neither risk factor (adjusted OR = 12.6; 95% CI, 7.5‐21.2). Discussion: Intrapartum temperature elevation among women receiving epidural analgesia, even if only to 99.6°F (37.6°C), is associated with approximately a 2‐fold increase in the occurrence of occiput posterior fetal head position at birth. Additionally, although this observational study cannot establish causal links, our findings suggest that the relationship between epidural‐related intrapartum temperature elevation and occiput posterior position at birth could contribute to an increased cesarean birth rate among women receiving epidural analgesia for pain relief in labor.     

Manual rotation in occiput posterior or transverse positions: risk factors and consequences on the cesarean delivery rate

OBJECTIVE: To identify the risk factors for failure of manual rotation in patients with occiput posterior or transverse positions during labor and to study the cesarean rate according to the success of the rotation. METHODS: Case-control study comparing failure and success of manual rotation. Cases were all fetuses for whom rotation failed. We used computerized randomization (without matching) to select one control with a successful rotation during the same period for each case with a failed rotation. Maternal, neonatal, and obstetric risk factors for failed rotation were studied with bivariable and multivariable analyses. Mode of delivery was analyzed according to success of the rotation. RESULTS: During the study period, manual rotations were performed in 796 patients. The procedure failed in 77 (9.7%) women. Attempted rotation before full dilatation tripled the risk of failure in comparison with rotation at full dilatation (adjusted odds ratio 3.4, 95% confidence interval 1.3-8.6), and rotation for failure to progress quadrupled that risk in comparison with prophylactic rotation (adjusted odds ratio 3.3, 95% confidence interval 1.2-8.5). Failure of manual rotation was associated with a higher cesarean delivery rate than was success (58.8% compared with 3.8%, P<.001). All women with unsuccessful manual rotations who delivered vaginally delivered in the occiput posterior position, and all women with successful manual rotation delivering vaginally delivered in the occiput anterior position. CONCLUSION: Manual rotation may be an effective technique for reducing the cesarean delivery rate in patients with an occiput posterior or transverse position during labor. The success or failure of attempted manual rotation depends upon obstetric conditions, including the indication for rotation and cervical dilatation.     

Associated factors and outcomes of persistent occiput posterior position: A retrospective cohort study from 1976 to 2001.

OBJECTIVE: To identify maternal and fetal risk factors associated with persistent occiput posterior position at delivery, and to examine the association of occiput posterior position with subsequent obstetric outcomes. METHODS: This is a retrospective cohort study of 30 839 term, cephalic, singleton births. Women with persistent occiput posterior (OP) position at delivery were compared to those with occiput anterior (OA) position. Demographics, obstetric history, and labor management were evaluated and subsequent obstetric outcomes examined. Potential confounding variables were controlled for using multivariate logistic regression analysis. RESULTS: The overall frequency of OP position was 8.3% in the study population. When compared to Caucasians, a higher rate of OP was observed among African-Americans (OR = 1.4, 95% CI 1.25-1.64) while no other racial/ethnic differences were noted. Other associated factors included nulliparity, maternal age > or =35, gestational age > or =41 weeks, and birth weight >4000 g, as well as artificial rupture of the membranes (AROM) and epidural anesthesia (p < 0.001 for all). Persistent OP was associated with increased rates of operative vaginal (OR = 4.14, 95% CI 3.57-4.81) and cesarean deliveries (OR = 13.45, 95% CI 11.94-15.15) and other peripartum complications including third or fourth degree perineal lacerations (OR = 2.38, 95% CI 2.03-2.79), and chorioamnionitis (OR = 2.10, 95% CI 1.81-2.44). CONCLUSION: Epidural use, AROM, African-American ethnicity, nulliparity, and birth weight >4000 g are associated with persistent OP position at delivery, with higher rates of operative deliveries and obstetric complications. This information can be useful in counseling patients regarding risks and associated outcomes of persistent OP position.     

Rebozo Technique for Fetal Malposition in Labor

Fetal occiput posterior position is associated with increased maternal and fetal morbidities. Currently, clinicians have limited evidence‐based techniques or tools to remedy fetal occiput posterior position. The traditional Mexican rebozo technique of pelvic massage, sifting, or jiggling offers a potentially valuable tool to help correct fetal malposition. This article reviews the adaptation of 3 rebozo techniques that can be used in labor to encourage optimum fetal positioning; outlines hospital considerations for safety, fetal heart rate monitoring, and universal precautions; and reviews the implementation plan to introduce and sustain use of the rebozo in a large academic medical center.     

Influence of persistent occiput posterior position on delivery outcome.

OBJECTIVE: To evaluate the influence of intrapartum persistent occiput posterior position of the fetal head on delivery outcome and anal sphincter injury, with reference to the association with epidural analgesia. METHODS: We conducted a prospective observational study of 246 women with persistent occiput posterior position in labor during a 2-year period, compared with 13,543 contemporaneous vaginal deliveries with occiput anterior position. RESULTS: The incidence of persistent occiput posterior position was significantly greater among primiparas (2.4%) than multiparas (1.3%; P <.001; 95% confidence interval 1.4, 2.4) and was associated with significantly higher incidences of prolonged pregnancy, induction of labor, oxytocin augmentation of labor, epidural use, and prolonged labor. Only 29% of primiparas and 55% of multiparas with persistent occiput posterior position achieved spontaneous vaginal delivery, and the malposition was associated with 12% of all cesarean deliveries performed because of dystocia. Persistent occiput posterior position was also associated with a sevenfold higher incidence of anal sphincter disruption. Despite a high overall incidence of use of epidural analgesia (47% versus 3%), the institutional incidence of persistent occiput posterior position was lower than that reported 25 years ago. CONCLUSION: Persistent occiput posterior position contributed disproportionately to cesarean and instrumental delivery, with fewer than half of the occiput posterior labors ending in spontaneous delivery and the position accounting for 12% of all cesarean deliveries for dystocia. Persistent occiput posterior position leads to a sevenfold increase in the incidence of anal sphincter injury. Use of epidural analgesia was not related to the malposition.     

The association between persistent occiput posterior position and neonatal outcomes

OBJECTIVE: To examine the effect of persistent occiput posterior position on neonatal outcome. METHODS: This is a retrospective cohort study of 31,392 term, cephalic, singleton births. Women with neonates born in persistent occiput posterior position at delivery were compared to those with occiput anterior position. Women with occiput transverse position were excluded. The association between occiput posterior position and neonatal outcomes, including 5-minute Apgar scores, umbilical cord gases, meconium-stained amniotic fluid, meconium aspiration syndrome, birth trauma, admission to the intensive care nursery, and length of stay were examined using chi(2) and Student t tests. Potential confounders (maternal age, ethnicity, parity, gestational age, epidural anesthesia, labor induction, length of labor, meconium, chorioamnionitis, birth weight, and year of delivery) were controlled for by using multivariable logistic regression and linear regression analyses. RESULTS: There were 2,591 (8.2%) neonates delivered in occiput posterior position of the total cohort of 31,392 deliveries. Compared with occiput anterior, neonates delivered in occiput posterior position had higher risks for adverse outcomes, including 5-minute Apgar score less than 7 (odds ratio [OR] 1.50, 95% confidence interval [CI] 1.17-1.91), acidemic umbilical cord gases (OR 2.05, 95% CI 1.52-2.77), meconium-stained amniotic fluid (OR 1.29, 95% CI 1.17-1.42), birth trauma (OR 1.77, 95% CI 1.22-2.57), admission to the intensive care nursery (OR 1.57, 95% CI 1.28-1.92), and longer neonatal stay in the hospital (OR 2.69, 95% CI 2.22-3.25). CONCLUSION: Persistent occiput posterior position at delivery is associated with higher risks of adverse neonatal outcomes compared with neonates delivered in the occiput anterior position. This information may be important in counseling women who experience persistent occiput posterior position in labor. Level of Evidence: II-2.     

持续性枕横位和枕后位病例的产程特点及影响

目的探讨持续性枕横位和枕后位的产程特点及对母儿结局的影响。方法回顾性分析64例持续性枕横位和51例持续性枕后位病例的各阶段产程时间、异常产程及产道损伤、产后出血、羊水粪染(Ⅱ°以上)、新生儿Apgar评分(5min评分≤7分)等情况,并与同期100例枕前位病例进行对比分析。结果持续性枕横位和枕后位的异常产程发生率、产道损伤、产后出血率均较对照组明显增加(P<0.05);羊水粪染及新生儿窒息发生率均较对照组明显增加,两组比较差异均有统计学意义(P<0.05)。结论重视对持续性枕横位和枕后位的早期诊断和及时处理对减少母儿并发症有重要意义。     

A Review of Evidence‐Based Practices for Management of the Second Stage of Labor

Management of the second stage of labor often follows tradition‐based routines rather than evidence‐based practices. This review of second‐stage labor care practices discusses risk factors for perineal trauma and prolonged second stage and scrutinizes a variety of care practices including positions, styles of pushing, use of epidural analgesia, and perineal support techniques. Current evidence for management of the second stage of labor supports the practices of delayed pushing, spontaneous (nondirected) pushing, and maternal choice of positions. Perineal compresses, perineal massage with a lubricant, and controlling the rate of fetal extension during crowning may prevent severe perineal trauma at birth. Supine positioning is not recommended. Upright positions and directed pushing can shorten the time from onset of second stage to birth and may be indicated in certain situations, although directed pushing has some associated risks. If the fetus is in the occiput posterior position, immediate pushing is not recommended, and manual rotation can be effective in correcting the malposition. Women should be informed of the potential effects of epidural analgesia on labor progress. Consultation and intervention to expedite birth may be indicated when birth is not imminent after 2 hours of active pushing, or 4 hours complete dilatation, for nulliparous women; or one hour of pushing, or 2 hours complete dilatation, for multiparous women. Each woman should be individually assessed and apprised of the potential risks to her and her fetus of a prolonged second stage of labor, and some women may choose to continue pushing beyond these time limits.     

Vaginal versus ultrasound examination of fetal occiput position during the second stage of labor

OBJECTIVE: The purpose of this study was to determine whether ultrasonography is more accurate than vaginal examination in the determination of fetal occiput position in the second stage of labor. STUDY DESIGN: Eighty-eight patients in the second stage of labor were evaluated by vaginal examination and by combined transabdominal and transperineal ultrasound examination to determine occiput position. These predictions of position were compared with the actual delivery position at vaginal delivery after spontaneous restitution or at cesarean delivery. Different examiners performed the vaginal examinations and the ultrasound examinations. Each examiner was blinded to the determination of the other examiner. RESULTS: Vaginal examination determined fetal occiput position correctly 71.6% of the time; ultrasound examination determined fetal occiput position correctly 92.0% of the time (P=.018). CONCLUSION: Ultrasound examination is more accurate than vaginal examination in the diagnosis of fetal occiput position in the second stage of labor.     

The evidence for physiologic management of the active phase of the first stage of labor

The active phase of first stage labor is generally defined as the period between 3 cm to 4 cm to complete cervical dilatation, in the presence of regular uterine contractions. Most women will experience this portion of labor within hospital obstetric units, where care commonly features restriction to bed, electronic fetal monitoring, early treatment of "slow" labors, and few pain management options beyond epidurals and narcotics. However, the available evidence on appropriate care for healthy childbearing women favors activity in labor, intermittent auscultation, patience from caregivers, and nonpharmacologic methods of pain relief. This article reviews the evidence for care practices that support physiologic labor. Modifying intrapartum care to reflect current evidence will improve women's health, and will require a multilevel approach and consistent midwifery demonstration of the model.     

Associated factors and outcomes of persistent occiput posterior position: A retrospective cohort study from 1976 to 2001

Objective. To identify maternal and fetal risk factors associated with persistent occiput posterior position at delivery, and to examine the association of occiput posterior position with subsequent obstetric outcomes.

Methods. This is a retrospective cohort study of 30 839 term, cephalic, singleton births. Women with persistent occiput posterior (OP) position at delivery were compared to those with occiput anterior (OA) position. Demographics, obstetric history, and labor management were evaluated and subsequent obstetric outcomes examined. Potential confounding variables were controlled for using multivariate logistic regression analysis.

Results. The overall frequency of OP position was 8.3% in the study population. When compared to Caucasians, a higher rate of OP was observed among African-Americans (OR = 1.4, 95% CI 1.25–1.64) while no other racial/ethnic differences were noted. Other associated factors included nulliparity, maternal age ≥35, gestational age ≥41 weeks, and birth weight >4000 g, as well as artificial rupture of the membranes (AROM) and epidural anesthesia (p < 0.001 for all). Persistent OP was associated with increased rates of operative vaginal (OR = 4.14, 95% CI 3.57–4.81) and cesarean deliveries (OR = 13.45, 95% CI 11.94–15.15) and other peripartum complications including third or fourth degree perineal lacerations (OR = 2.38, 95% CI 2.03–2.79), and chorioamnionitis (OR = 2.10, 95% CI 1.81–2.44).

Conclusion. Epidural use, AROM, African-American ethnicity, nulliparity, and birth weight >4000 g are associated with persistent OP position at delivery, with higher rates of operative deliveries and obstetric complications. This information can be useful in counseling patients regarding risks and associated outcomes of persistent OP position.     

Research on the progress of the fetal head in the occipito-posterior position

We have studied by means of B type ultrasound, the fetal positions and their progress in 221 cases, among which 117 were serially observed. The results showed a marked increase in the incidence of occipito-posterior position (OP) after onset of labor and marked decrease of occipito-anterior position (OA). The antepartum fetal position was influenced mainly by placental site but during labor also by the type and size of the pelvis. The incidence of OP after onset of labor was 33.03% of which 53.13% could rotate spontaneously to anterior position and be delivered as such but 29.69% remained as persistent occipito-posterior position (POP). We also discussed about the differences in the duration and types of deliveries in OP as determined by different labor processes as well as the relationship between the different labor processes and the three major factors affecting labor, particularly in occiput left posterior and occiput right posterior positions.     

Occiput posterior fetal head position increases the risk of anal sphincter injury in vacuum-assisted deliveries

OBJECTIVE: The purpose of this study was to determine whether an occiput posterior (OP) fetal head position increases the risk for anal sphincter injury when compared with an occiput anterior (OA) position in vacuum-assisted deliveries. STUDY DESIGN: We conducted a retrospective cohort study of 393 vacuum-assisted singleton vaginal deliveries. Maternal demographics and obstetric and neonatal data were collected from an obstetric database and chart review. RESULTS: Within the OP group, 41.7% developed a third- or fourth-degree laceration compared with 22.0% in the OA group (OR 2.5, 95% CI 1.4-4.7). In a logistic regression model that controlled for BMI, race, nulliparity, length of second stage, episiotomy, birth weight, head circumference, and fetal head position, OP position was 4.0 times (95% CI 1.7-9.6) more likely to be associated with an anal sphincter injury than OA position. CONCLUSION: Among vacuum deliveries, an OP head position confers an incrementally increased risk for anal sphincter injury over an OA position.     

产程中胎儿安全监测

产程中胎儿监测方法主要有胎心听诊,胎儿电子监护、胎儿血气分析及胎儿脉冲血氧测定等,上述方法的合理应用,能及时判定胎儿有无缺氧,以便适时干预,从而保障胎儿在产程中的安全。     

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.