Malpositions and malpresentations of the fetal head

Nearly 95% of fetuses at term present with the vertex and with such a presentation, the vast majority of women progress well in labour and have a spontaneous vaginal delivery. Any presentations other than vertex can lead to difficulties in labour and hence are called as malpresentations.Malpresentations of fetal head occur due to extension of the fetal head causing brow or face to present during labour. Malpositions of fetal head result when the occiput persists in a lateral or posterior position. Malpresentations and malpositions of fetal head are usually diagnosed in labour and are associated with difficult labour and increased risk of operative intervention. Regular systematic clinical examinations to monitor progress of labour and fetal wellbeing are necessary once fetal malpresentations or malpositions are diagnosed. Although vaginal delivery is possible in many cases, caesarean section becomes necessary when the malposition or malpresentation persists and labour fails to progress.     

Ultrasonographic occiput position in early labour in the prediction of caesarean section

OBJECTIVE: To investigate the value of ultrasonographically determined occiput position in the early stages of the active phase of labour, in addition to traditional maternal, fetal and labour-related characteristics, in the prediction of the likelihood of caesarean section. DESIGN: Prospective observational study. SETTING: District general hospital in the UK. POPULATION: Six hundred and one singleton pregnancies with cephalic presentation in active labour at term with cervical dilatation of 3-5 cm. METHODS: Transabdominal sonography to determine fetal occiput position was carried out by an appropriately trained sonographer immediately before or after the routine clinical examination by the attending midwife or obstetrician. MAIN OUTCOME MEASURE: Caesarean section. RESULTS: Delivery was vaginal in 514 (86%) cases and by caesarean section in 87 (14%). The fetal occiput position was posterior in 209 (35%) cases and in this group the incidence of caesarean section was 19% (40 cases), compared with 11% (47 of 392) in the non-occiput posterior group. Multiple regression analysis revealed that significant independent contribution in the prediction of caesarean section was provided by maternal age (OR 1.1, 95% CI 1.0-1.2), Afro-Caribbean origin (OR 2.4, 95% CI 1.2-4.6), height (OR 0.93, 95% CI 0.89-0.97), parity (OR 0.2, 95% CI 0.1-0.4), type of labour (OR 2.2, 95% CI 1.3-3.8), gestation (OR 1.4, 95% CI 1.1-1.7), fetal head descent (OR 0.6, 95% CI 0.4-0.9), occiput posterior position (OR 2.2, 95% CI 1.3-3.7) and male gender (OR 2.0, 95% CI 1.2-3.5). CONCLUSIONS: The risk of caesarean section can be estimated during the early stage of active labour by the sonographically determined occiput position, in addition to traditional maternal, fetal and labour-related characteristics.     

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.     

持续性枕横位及枕后位的产程特点及围产儿预后

目的：探讨持续性枕横位及枕后位的产程特点及围产儿预后。方法：采用回顾性资料分析方法，对１９９５年１１月至１９９６年７月在我院分娩的持续性枕横位及枕后位孕妇的临床资料进行分析。并与同期枕位正常的９０例（对照组）孕妇进行比较。结果：枕位异常者，胎儿体重过大、宫缩乏力的比例明显增加，产程各期时间均明显延长，胎先露下降速度明显减慢，各产程异常发生率明显增加，手术产率明显增加。枕横位总手术产率为８２．８１％，枕后位为９２．３１％，胎儿宫内缺氧、新生儿窒息率明显增加。结论：持续性枕横位及枕后位是难产的主要原因之一，若处理不当，围产儿预后欠佳。     

Maternal positioning and fetal positioning in utero

AIM: Approximately two-thirds of term vertex fetuses are in the left occiput position in utero. However, little is understood about the physiology of maternal-fetal positioning during pregnancy. It was hypothesized that fetal left occiput positioning is affected by maternal positioning. The present study was designed to investigate the relationship between maternal positioning in late pregnancy and fetal positioning in utero. METHODS: A prospective cohort study was conducted at Ueda Hospital, Kobe, Japan. Eligible women were limited to low-risk pregnancies ending in spontaneous vaginal delivery with singleton vertex fetuses. Information obtained from the mother included the preference of positioning during sleep in the second half of pregnancy. Fetal information recorded after delivery included fetal positioning. RESULTS: Eighty-one (50.6%) of 160 evaluated women preferred left lateral positioning while 70 (43.8%) women preferred right lateral positioning in the second half of pregnancy. Seventy-seven (51.7%) of 149 evaluated fetuses were in the left occiput position while 72 (48.3%) fetuses were in the right occiput position in utero. Maternal left lateral positioning with fetal left occiput position in utero was the predominant positioning (41 of 149, 27.5%). However, there was no statistical relationship between maternal positioning and fetal occiput positioning in utero. CONCLUSION: More women prefer the left lateral position during the second half of pregnancy. More fetuses are in the left occiput in utero during the late stage of pregnancy. However, no statistical relationship was observed between maternal and fetal positioning.     

Malpositions and malpresentations of the foetal head

The normal way for a baby to deliver is by the vertex with the occiput lying anteriorly. With a cephalic presentation, if the occiput is not lateral in early labour or anterior in advanced labour then a malposition exists. If the leading pole of the foetus is anything other than the vertex, a malpresentation exists. Malpositions of the vertex and malpresentations of the foetal head usually present in labour and while birth can proceed normally, a more difficult labour is common and operative delivery is more likely, with attendant risks to both the mother and the baby. This article will describe these conditions, the clinical features associated with them and how to recognise and manage them.     

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.     

Occipito-posterior fetal head position, maternal and neonatal outcome

The purpose of this review is to summarize the available evidence on occipito-posterior fetal head position and maternal and neonatal outcome. The occipito-posterior fetal head position is the most common malposition, but there are not so many data about it in literature. Its incidence is ranging from 1.8% by Fitzpatrick, to 4.6% and 5.5% by Yancey and Sizer, to 6% by Ponkey. Only two trials studied the occipito-posterior associated factors. There are lower incidence of premature rupture of membrane, arterial hypertension pregnancy-induced, induced labour, increased of episiotomy, instrumental delivery and a decreased of vaginal birth without a difference in neonatal Apgar, and with a neonatal bigger weight. The occipito-posterior fetal head position persistence compared to anterior position, has a statistically significant association with low maternal stature, previous cesarean section, longer first and second stage of labour, oxytocin augmentation, epidural analgesia, instrumental vaginal delivery, chorion-amniositis, vaginal perineal injures, loss of blood and post partum infections. A highest incidence of occipito-posterior fetal head position may depend by nulliparity, malnutrition with pelvic deformity, pelvic immaturity in the teenager and anterior placenta. Epidural analgesia is a risk factor for fetal head malposition. The majority of occipito-posterior fetal head positions is not due to a malrotation, but to a persistence in this position of the fetal head. In fact, this persistence leads to a failure of the fetal head rotation. The prolonged second stage is often the result of occipito-posterior fetal head position and instrumental delivery is required. The traditional vaginal examination is not useful for the determination of fetal head position, so and instrumental method is needed, such as ultrasound, for a correct evaluation of fetal head position, particularly if a vaginal instrumental delivery is necessary. This is recommended by the Canadian Society of Obstetrics and Gynecology. The evaluation of fetal head position is important in the prediction of labour induction.     

Asynclitism: a literature review of an often forgotten clinical condition

Asynclitism is defined as the “oblique malpresentation of the fetal head in labor”. Asynclitism is a clinical diagnosis that may be difficult to make; it may be found during vaginal examination. It is significant because it may cause failure of progress operative or cesarean delivery. We reviewed all literature for asynclitism by performing an extensive electronic search of studies from 1959 to 2013. All studies were first reviewed by a single author and discussed with co-authors. The following studies were identified: 8 book chapters, 14 studies on asynclitism alone and 10 papers on both fetal occiput posterior position and asynclitism. The fetal head in a laboring patient may be associated with some degree of asynclitism; this is seen as usual way of the fetal head to adjust to maternal pelvic diameters. However, marked asynclitism is often detected in presence of a co-existing fetal head malposition, especially the transverse and occipital posterior positions. Digital diagnosis of asynclitism is enhanced by intrapartum ultrasound with transabdominal or transperineal approach. The accurate diagnosis of asynclitism, in an objective way, may provide a better assessment of the fetal head position that will help in the correct application of vacuum and forceps, allowing the prevention of unnecessary cesarean deliveries.     

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.     

The Fetal Occiput Posterior Position: State of the Science and a New Perspective

Abstract: Background: The fetal occiput posterior position poses challenges in every aspect of intrapartum care—prevention, diagnosis, correction, supportive care, labor management, and delivery. Maternal and newborn outcomes are often worse and both physical and psychological traumas are more common than with fetal occiput anterior positions. The purpose of this paper is to describe nine prevailing concepts that guide labor and birth management with an occiput posterior fetus, and summarize evidence to clarify the state of the science. Methods: A search was conducted of the databases of PubMed and the Cochrane Library. Additional valuable information was obtained from obstetric and midwifery textbooks, books and websites for the public, conversations with maternity care professionals, and years of experience as a doula. Results: Nine prevailing concepts are as follows: (1) prenatal maneuvers rotate the occiput posterior fetus to occiput anterior; (2) it is possible to detect the occiput posterior fetus prenatally; (3) a fetus who is occiput anterior at the onset of labor will remain in that position throughout labor; (4) back pain in labor is a reliable sign of an occiput posterior fetus; (5) the occiput posterior fetus can be identified during labor by digital vaginal examination; (6) an ultrasound scan is a reliable way to detect fetal position; (7) maternal positions facilitate rotation of the occiput posterior fetus; (8) epidural analgesia facilitates rotation; (9) manual rotation of the fetal head to occiput anterior improves the rate of occiput anterior deliveries. Concepts 1, 2, 3, 4, 5, and 8 have little scientific support whereas concepts 6, 7, and 9 are supported by promising evidence. Conclusions: Many current obstetric practices with respect to the occiput posterior position are unsatisfactory, resulting in failure to identify and correct the problem and thus contributing to high surgical delivery rates and traumatic births. The use of ultrasound examination to identify fetal position is a method that is far superior to other methods, and has the potential to improve outcomes. Research studies are needed to examine the efficacy of midwifery methods of identification, and the effect of promising methods to rotate the fetus (simple positional methods and digital or manual rotation). Based on the findings of this review, a practical approach to care is suggested. (BIRTH 37:1 March 2010)     

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.     

Dystocia in late labor: determining fetal position by clinical and ultrasonic techniques

A failure of adequate progression during late labor occurs often and may prohibit an accurate determination of the fetal head position from scalp edema or caput formation. This investigation was undertaken to determine whether ultrasonic evaluation could confirm or correct the digital examination impressions of the fetal head position. Eighty-six attempted vaginal deliveries had recent evidence for arrested cervical dilation after 7 cm or more. An occiput transverse position in 24 (28%) cases was diagnosed accurately, with the need for additional ultrasonic information only in the presence of scalp edema. Distinguishing between a persistent occiput posterior (15 cases, 17%) or anterior (47 cases, 55%) position was often inexact by palpation alone. Combined clinical and ultrasonic impressions allowed for a significantly more precise diagnosis. Ultrasonic imaging allowed for more security while waiting, more confidence with midforceps application, or a prompter decision for cesarean section, depending on the head position.     

胎儿体重对持续性枕后位产程特征和分娩结局影响的分析

目的:探讨胎儿体重对持续性枕后位产程特征和分娩结局的影响.方法:对2005年12月至2009年12月在本院产科住院分娩228例持续性枕后位产妇的临床资料进行回顾性分析,根据新生儿出生体重分为对照组112例(胎儿体重≥2500 g且＜3500 g)和研究组116例(胎儿体重≥3500 g且＜4250 g).并将两组产程特征、母儿结局进行分析比较.结果:两组产妇产程异常(宫口扩张延缓、停滞,胎头下降延缓、停滞)发生率、临床干预(体位矫正、手转胎头)成功率、剖宫产率、母儿并发症(产后出血、产褥病率、胎儿窘迫、新生儿窒息)发生率差异均有统计学意义(P＜0.05).结论:持续性枕后位产程处理中充分考虑胎儿的体重因素,对于胎儿估计体重≥3500 g的枕后位病例应积极临床干预,干预失败应放宽手术指征,以降低母儿并发症发生率.     

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.     

Active Management of Labour

Far more than oxytocin augmentation, active management implies “skillful handling” of labour. Recognizing that a knowledge and awareness of the process of labour will influence a woman’s response to uterine activity and her sense of wellbeing, antenatal instruction is the first component of active management. An accurate diagnosis of labour will avoid creating mis-conceptions on the part of the woman and her family support and will reduce the likelihood of inappropriate intervention for a mistaken diagnosis of dystocia. Active management involves the provision of continuous support, reassurance, and comfort for the woman in labour, and recognizes the benefits of these in promoting the normal progress of labour and in reducing the need for analgesic pharmacology. Maternal and fetal surveillance are necessary to ensure that mother and fetus remain well during labour, but such surveillance is not the sole focus of intrapartum care, and effective fetal surveillance can be achieved best through intermittent fetal heart auscultation. Once in the active phase of labour (cervix fully effaced, 3–4 cm dilated), active management demands that caregivers ensure that continuous progress is made towards full dilatation and delivery. This is achieved through regular pelvic examination. If dystocia occurs once the unusual situation of frank disproportion has been excluded, artificial rupture of the membranes and oxytocin augmentation should be instituted. In the second stage of labour, progress should be continued, an absence of appreciable progress rather than any arbitary time period being an indication for intervention. Such arrested progress may respond to oxytocin augmentation, particularly in the presence of regional analgesia. Maternal expulsive efforts should be withheld until they are likely to be productive, that is once the head has reached the perineum. They may be initiated earlier in a last effort to avoid operative delivery in situations where head descent has ceased in spite of oxytocin augmentation.     

多导睡眠图在儿童阻塞性睡眠呼吸暂停低通气综合征及鼾症中的应用

目的探讨阻塞性睡眠呼吸暂停低通气综合征(OSAHS)儿童及鼾症儿童多导睡眠图的特点及多导睡眠图对儿童睡眠障碍的临床应用价值。 方法对2002年12月至2004年9月新疆医科大学第一附属医院儿科74例OSAHS儿童及62例同年龄组原发性鼾症儿童进行整夜多导睡眠(PSG)监测，并进行比较，观察呼吸紊乱指数、觉醒次数、周期性腿动指数、睡眠最低血氧饱和度等16项指标。 结果与鼾症组相比，OSAHS儿童周期性腿动指数、呼吸紊乱指数、平均血氧饱和度、最低血氧饱和度、发生在非快速眼动期的呼吸紊乱指数有显著性差异(P<0.05)。 结论PSG是鉴别诊断儿童OSAHS与鼾症的重要方法，通过对PSG各项指标进行比较，强调PSG是诊断儿童睡眠有关疾患，特别是OSAHS的分型、病情评价的有用和重要方法。     

新式头位分娩评分法对判断初产妇持续性枕横位、枕后位分娩方式的临床价值

目的:设计一种在临床上能更及时、准确地做出顺产与难产判断的头位分娩评分法,并探讨其对判断初产妇持续性枕横位、枕后位分娩方式的临床价值。方法:拟定新式头位分娩评分法,对236例诊断为持续性枕横位、枕后位的初产妇进行临床分析。结果:新式头位分娩评分法总分小于70分者,90.63%行剖宫产术,大于80分者91.49%经阴道分娩(P<0.01),无一例严重母婴并发症发生。结论:新式头位分娩评分法全面地对整个产程及胎儿情况进行量化评分,对顺产与难产做出综合判断,在确保母婴安全的情况下,尽可能地降低了剖宫产率。     

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.     

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.