Uterine contractility in women whose fetus is delivered in the occipitoposterior position

OBJECTIVE: Most fetuses in the occipitoposterior position rotate spontaneously after striking the pelvic floor. The increased prevalence of prolonged labor, operative delivery, and oxytocin augmentation in women with an occipitoposterior fetal position seems consistent with decreased uterine contractility. We sought to test the hypothesis that women with a persistent occipitoposterior fetal position have inadequate intrauterine pressure. STUDY DESIGN: Intrauterine pressure was measured prospectively electronically in 94 women whose labor pain was controlled by patient-requested epidural analgesia. Eleven women (12%) were delivered as a persistent occipitoposterior fetal position. In a nested case-control study, these women were compared with 22 women who were delivered as an occipitoanterior fetal position who were matched for age, parity, gestational age, cervical examination at study enrollment, and body mass index. The intrauterine pressure measurements were initiated during the first stage of labor and continued throughout the entire labor process. Women were encouraged in the second stage of labor, after a period of recording baseline contractility, to push using a standardized Valsalva maneuver once the vertex reached the +2 station. The area under the intrauterine pressure curve (integral) was used to estimate uterine contractility and expulsive performances. RESULTS: Five women (45%) in the occipitoposterior group required operative delivery. The average duration of the second stage of labor in the occipitoposterior group was 91.4 +/- 23.2 minutes compared with 51.7 +/- 6.6 minutes in the occipitoanterior fetal position (P =.04). Ninety percent of women in the occipitoposterior group required oxytocin, compared with 59% of the women in the occipitoanterior group (P =.11). There were no differences in uterine contractility between occipitoposterior and occipitoanterior groups during either the first stage of labor (integral mean +/- SEM: occipitoposterior [1685.3 +/- 194.6 mm Hg. s] vs occipitoanterior fetal position [1700.8 +/- 128.9 mm Hg. s, P =.98]) or second stages of labor (occipitoposterior [1952.6 +/- 186.5 mm Hg. s] vs occipitoanterior fetal position [1740.8 +/- 104.3 mm Hg. s, P =.46]). Further, there were no significant differences in pushing performances between the occipitoposterior and occipitoanterior groups (Valsalva maneuver: occipitoposterior 2864.9 +/- 328.8 mm Hg. s] vs occipitoanterior [2898.6 +/- 222.2 mm Hg. s, P =.90]). CONCLUSION: Women who were delivered as a persistent occipitoposterior fetal position do not have lower intrauterine pressure levels immediately before or during the second stage of labor.     

Have Kielland Forceps Reached Their ''Use By'' Date?

Kielland forceps have long been used in Australian hospitals for rotation and delivery from occipitolateral and occipitoposterior positions. We have studied the pattern and use of these forceps in our hospital, and conducted a statewide survey of obstetric trainees about their experience with Kielland forceps. We conclude that current obstetric training programmes are unlikely to provide registrars with sufficient skill in their safe use.     

Use of intrathecal analgesia in a rural hospital Case studies

A woman's experience of unrelenting back pain with a fetus in an occipitoposterior position and the escalating interventions culminating in a cesarean birth is every midwife's nightmare. Intrathecal analgesia is a relatively simple and rapid method to provide maternal relaxation and relief from severe back labor. This article describes the use of intrathecal opioid analgesia in labor complicated by failure to progress in first-stage labor due to persistent occipitoposterior position of the fetus. Intrathecal analgesia has the advantage of being inexpensive and providing rapid onset of adequate pain relief for the first stage of labor. It does not cause motor blockade, so it allows the mother to be mobile and feel the urge to push. Consequently, there is no associated risk of an increased need for forceps or vacuum-assisted delivery. The authors note a decreased incidence of operative delivery for fetal occipitoposterior position with the use of intrathecal narcotics.     

USE OF INTRATHECAL ANALGESIA IN A RURAL HOSPITAL: Case Studies

A woman's experience of unrelenting back pain with a fetus in an occipitoposterior position and the escalating interventions culminating in a cesarean birth is every midwife's nightmare. Intrathecal analgesia is a relatively simple and rapid method to provide maternal relaxation and relief from severe back labor. This article describes the use of intrathecal opioid analgesia in labor complicated by failure to progress in first-stage labor due to persistent occipitoposterior position of the fetus. Intrathecal analgesia has the advantage of being inexpensive and providing rapid onset of adequate pain relief for the first stage of labor. It does not cause motor blockade, so it allows the mother to be mobile and feel the urge to push. Consequently, there is no associated risk of an increased need for forceps or vacuum-assisted delivery. The authors note a decreased incidence of operative delivery for fetal occipitoposterior position with the use of intrathecal narcotics.     

Randomized Controlled Trial of Hands‐and‐Knees Positioning for Occipitoposterior Position in Labor

ABSTRACT: Background: Hands‐and‐knees positioning during labor has been recommended on the theory that gravity and buoyancy may promote fetal head rotation to the anterior position and reduce persistent back pain. A Cochrane review found insufficient evidence to support the effectiveness of this intervention during labor. The purpose of this study was to evaluate the effect of maternal hands‐and‐knees positioning on fetal head rotation from occipitoposterior to occipitoanterior position, persistent back pain, and other perinatal outcomes. Methods: Thirteen labor units in university‐affiliated hospitals participated in this multicenter randomized, controlled trial. Study participants were 147 women laboring with a fetus at ≥37 weeks’ gestation and confirmed by ultrasound to be in occipitoposterior position. Seventy women were randomized to the intervention group (hands‐and‐knees positioning for at least 30 minutes over a 1‐hour period during labor) and 77 to the control group (no hands‐and‐knees positioning). The primary outcome was occipitoanterior position determined by ultrasound following the 1‐hour study period and the secondary outcome was persistent back pain. Other outcomes included operative delivery, fetal head position at delivery, perineal trauma, Apgar scores, length of labor, and women's views with respect to positioning. Results: Women randomized to the intervention group had significant reductions in persistent back pain. Eleven women (16%) allocated to use hands‐and‐knees positioning had fetal heads in occipitoanterior position following the 1‐hour study period compared with 5 (7%) in the control group (relative risk 2.4; 95% CI 0.88–6.62; number needed to treat 11). Trends toward benefit for the intervention group were seen for several other outcomes, including operative delivery, fetal head position at delivery, 1‐minute Apgar scores, and time to delivery. Conclusions: Maternal hands‐and‐knees positioning during labor with a fetus in occipitoposterior position reduces persistent back pain and is acceptable to laboring women. Given this evidence, hands‐and‐knees positioning should be offered to women laboring with a fetus in occipitoposterior position in the first stage of labor to reduce persistent back pain. Although this study demonstrates trends toward improved birth outcomes, further trials are needed to determine if hands‐and‐knees positioning promotes fetal head rotation to occipitoanterior and reduces operative delivery. (BIRTH 32:4 December 2005)     

Vacuum-assisted delivery

Unsuccessful vacuum extraction, cup detachment and failed anterior rotation in occipitoposterior positions are commonly associated with obstetric factors that are avoidable or correctable. These factors include the preferential use of soft vacuum cups, incorrect cup applications and attempts to deliver with the vacuum extractor before the cervix is completely dilated. Evidence from randomized trials demonstrates that soft cups cause fewer cosmetic effects and scalp lacerations than rigid cups. Soft cups do not reduce the incidence of cephalhaematomas nor have they been shown to provide any advantage over rigid cups for the prevention of subgaleal haemorrhage. Clinically significant subgaleal haemorrhage and intracranial injury are almost always preceded by difficult vacuum extraction. Although the vacuum extractor is less likely than forceps to injure the mother's genital tract and anal sphincters at delivery, no significant differences have been demonstrated between the instruments in terms of subsequent urinary or bowel disturbances.     

Malpresentations--impact on mode of delivery

Fetal malpresentation, including persistent occipitoposterior position, is a major cause of dystocia resulting in obstetric interventions. We studied malpresentation among 11 957 consecutive singleton deliveries from 1995 to 2004. There were 1 030 deliveries with a malpresentation (8.6%). Cephalic malpresentations occurred in 5.4% of deliveries (persistent occipitoposterior 5.2%, face 0.1%, brow 0.14%), and 3.1% had breech presentation and 0.12% a transverse lie. The odds ratios (OR) for cesarean section were 14.89 (95%CI 11.91-18.63) in breech presentation and 4.57 (95% CI 3.85-5.42) in persistent occipitoposterior presentation. With persistent occipitoposterior position, the OR for instrumental vaginal delivery was 3.84 (95%CI 3.14-4.70). Primiparity was associated with increased malpresentation risks, as 54.6% of those with malpresentations were primiparous compared with 41.7% of those without (OR 1.68, 95%CI 1.48-1.91, p < 0.001). Primiparous women required more cesarean sections (OR 1.92, 95%CI 1.50-2.47) and instrumental deliveries (OR 2.89, 95%CI 1.50-2.47). Malpresentation frequently leads to cesarean section or instrumental delivery, especially among primiparous women.     

Kielland产钳在持续性枕后位中的应用

目的 评估Ｋｉｅｌｌａｎｄ产钳对持续性枕后位进行反置上钳旋转胎头的安全性及可行性。方法 对１００例胎头双顶径已达或已过坐骨棘水平的持续性枕后位产妇,用Ｋｉｅｌｌａｎｄ产钳进行反置上钳旋转胎头产钳术。结果 成功率１００％,母体软产道损伤１７％,新生儿损伤１２％,无会阴Ⅲ度裂伤,无后穹窿,宫颈,膀胱损伤及子宫破裂,无新生儿颅内出血及死亡等严重并发症,结论 Ｋｉｅｌｌａｎｄ产钳反置上钳旋转胎头术用于双顶     

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.     

Does ultrasonographic foetal head position prior to induction of labour predict the outcome of delivery?

Objective

To examine the capacity of pre-induction sonographic assessment of occipital position of the foetal head to predict the outcome of delivery, and to assess whether sonographic foetal head position before induction of labour is related to foetal presentation at delivery.

Study design

A prospective cohort study was conducted in the Máxima Medical Centre, The Netherlands. We included consecutive women in whom labour was induced. Immediately prior to induction a transabdominal ultrasound was performed to determine the position of the foetal occiput. The primary outcome was mode of delivery. We recorded maternal demographics, labour and delivery characteristics, maternal and neonatal outcomes. The association between position of the foetal head before induction of labour and the occurrence of caesarean section was addressed using univariable and logistic regression analysis.

Results

From the 50 of the 183 foetuses that started labour in occipitoposterior position, 11 persisted in occipitoposterior position until birth, whereas from the 120 foetuses that were in occipitoanterior position before induction, three children were born in an occipitoposterior position. Although we found a difference in caesarean section rate between OP position and OA position of the foetal head at sonography prior to induction, this was not statistically significant (14% versus 6.7%, OR 2.3, 95% CI 0.78–6.7).

Conclusion

Our study demonstrates that OP position prior to labour induction does not affect mode of delivery. Sonographic assessment of the position of the foetal head prior to labour induction should not be introduced in clinical practice.     

Does fetal head position at the term plus 12 scan influence induction, labor and delivery outcome?

AIMS: To assess the influence that fetal head position has on induction, labor and delivery outcome for both mother and baby. METHODS: During a one month period, in November 1999, all women attending for a post-dates scan were enrolled as the study population. In total, 91 women formed our study population for analysis of data. The sonographic, induction and labor details of all women were recorded on a dedicated data sheet. As well as documenting the maternal age, parity, liquor volume (mm) and BPS, the position of the fetal head was noted by the sonographer as occipitoanterior, occipitotransverse or occipitoposterior. All women had gestation confirmed by ultrasound early during the course of their pregnancy. Maternal, ultrasonographic, induction and labor variables were correlated with fetal head presentation at scan. RESULTS: There was no positive correlation found between fetal head position at the term plus 12 scan and associated induction, labor or delivery complications in the 91 women studied. CONCLUSIONS: Our study shows no positive correlation between fetal head position and induction, labor or delivery complications.     

The anatomy of obstetric litigation

A review of 110 cases of litigation for birth related injuries has been undertaken. 70% of the claims were associated with abnormalities of the CTG. Breech presentation, the occipitoposterior position and the occurrence of twins were all risk factors and the Registrar Grade were most frequently involved in litigation.The aetiology of cerebral palsy remains obscure, but there can be no doubt that it is multifactorial in origin. It seems likely that intrapartum asphyxia accounts for a small proportion of cases¹ and yet obstetric litigation for cerebral damage and mental retardation has become a major factor in obstetric practice and an unpleasant fact of life for the obstetrician and the midwife.The search for a cause for the adverse outcome relates firstly to the need to apportion blame and secondly to obtain compensation which may be essential in making life tolerable for the parents in supporting their handicapped child.It is important to examine the pattern of management, if any, that may predate the claim and to try and identify common factors in order that both the patient and the obstetrician may be protected.     

Mediolateral episiotomy reduces the risk for anal sphincter injury during operative vaginal delivery

Objective  To determine the risk factors for anal sphincter injuries during operative vaginal delivery.
Setting and design  A population-based observational study.
Population  All 21 254 women delivered with vacuum extraction and 7478 women delivered with forceps, derived from the previously validated Dutch National Obstetric Database from the years 1994 to 1995.
Methods  Anal sphincter injury was defined as any injury, partial or complete, of the anal sphincters. Risk factors were determined with multivariate logistic regression analysis.
Main outcome measures  Individual obstetric factors, e.g. fetal birthweights, duration of second stage, etc.
Results  Anal sphincter injury occurred in 3.0% of vacuum extractions and in 4.7% of forceps deliveries. Primiparity, occipitoposterior position and fetal birthweight were associated with an increased risk for anal sphincter injury in both types of operative vaginal delivery, whereas duration of second stage was associated with an increased risk only in vacuum extractions. Mediolateral episiotomy protected significantly for anal sphincter damage in both vacuum extraction (OR 0.11, 95% CI 0.09–0.13) and forceps delivery (OR 0.08, 95% CI 0.07–0.11). The number of mediolateral episiotomies needed to prevent one sphincter injury in vacuum extractions was 12, whereas 5 mediolateral episiotomies could prevent one sphincter injury in forceps deliveries.
Conclusions  Primiparity and occipitoposterior presentation are strong risk factors for the occurrence of anal sphincter injury during operative vaginal delivery. The highly significant protective effect of mediolateral episiotomies in both types of operative vaginal delivery warrants the conclusions that this type of episiotomy should be used routinely during these interventions to protect the anal sphincters.     

Abnormal labour: an evidence-based approach

Group B streptococci (GBS) are bacteria that colonise the genital tract in a significant proportion of pregnant women. Bacteriological screening of the low vagina is positive in 22% of women but this figure increases to 27% if the rectum is also swabbed. Early-onset GBS sepsis in the neonate is associated with significant morbidity and mortality. GBS infection is more likely following prolonged rupture of the membranes, and intrapartum antibiotic prophylaxis significantly reduces the incidence of early-onset neonatal sepsis. Secondary arrest of labour occurs in 6% of nulliparous women and 2% of multiparous women. One of the causes of secondary arrest is an occipitoposterior position. Breech presentation is associated with higher rates of perinatal morbidity and mortality. External cephalic version reduces the incidence of noncephalic presentation. This article describes three case scenarios highlighting these problems, and provides a rational clinical approach to them based on available evidence.     

Aortic compression by the uterus: identification with the Finapres digital arterial pressure instrument

Summary. Aortic compression by the uterus at term was diagnosed when reversible reductions in toe pulse pressure, measured using a Finapres digital blood pressure instrument, were found in the absence of systemic hypotension, monitored by a second instrument with the cuff on a finger. Aortic compression was found in the left or right pelvic tilt positions in 14 of 32 women, sometimes with up to 34° of tilt, and was relieved by increasing the amount of tilt, except in a twin pregnancy where compression became more severe as left pelvic tilt was increased from 13° to 28°. Compression was also found in two women in the semirecumbent position. Factors associated with an increased likelihood of aortic compression were non-engagement of the fetal head, occipitoposterior position of the fetal head, and cervical dilatation less than 5 cm.     

Efficacy of the fetal-pelvic index as a predictor of fetal-pelvic disproportion in women with abnormal labor patterns that require labor augmentations

The fetal-pelvic index, which compares fetal head and abdomen circumferences with respective maternal inlet and midpelvic circumferences, was introduced in 1986 as a means of identifying the presence or absence of fetal-pelvic disproportion. In this study the efficacy of the fetal-pelvic index was evaluated in 46 patients with abnormal labor patterns that required labor augmentations and was compared with that of two other means (Colcher-Sussman x-ray pelvimetry and ultrasonographically derived estimated fetal weight greater than or equal to 4000 gm). Of the 24 women who required operative intervention (19 cesarean sections and five operative vaginal procedures), 17 had positive fetal-pelvic index values (sensitivity = 0.71). Six of the seven fetuses of patients with false-negative fetal-pelvic index values persisted in an occipitoposterior presentation, and these patients failed to progress in labor. Of the 22 patients in whom vaginal deliveries were spontaneous, 21 had negative fetal-pelvic index values (specificity = 0.95). Of the 18 women with positive fetal-pelvic index values, 17 required operative intervention (positive predictability = 0.94). In contrast, when used alone, neither x-ray pelvimetry nor ultrasonographically derived estimated fetal weight greater than or equal to 4000 gm provided accurate identification of fetal-pelvic disproportion.     

Rotational delivery of the fetus: Kielland's forceps and two other methods compared

Summary. A retrospective comparison was undertaken of 552 cases in which Kielland's forceps were used for rotation and delivery, 95 cases in which other forceps were used for rotation and delivery, and 160 cases in which manual rotation and forceps were used. There was no significant difference in maternal or fetal morbidity between the three groups, regardless of whether the indication for delivery was delay in the second stage of labour or fetal distress. When Kielland's forceps were used by junior staff, significantly more vaginal and cervical lacerations and primary postpartum haemorrhage occurred, but there was no increase in fetal morbidity.     

Obstetrics and gynecology resident satisfaction with an integrated, comprehensive abortion rotation

OBJECTIVE: To evaluate obstetrics and gynecology resident satisfaction with a comprehensive, integrated abortion rotation. METHODS: The University of California, San Francisco obstetrics and gynecology residency program includes a 6-week PGY-3 family planning rotation at an in-hospital clinic where abortions are provided up to 23 weeks of gestation. Residents annually evaluate the educational value of all clinical rotations on a 5-point Likert scale, with 5 indicating "maximum value," and 1 "no value." Using data from 1998-2003, we compared ratings of the family planning rotation with all other PGY-3 rotations. We also surveyed residents 1 to 3 years after graduation to assess the rotation qualitatively and quantitatively. RESULTS: Forty residents completed the abortion training, none opted out of training, and all completed the evaluations. Of all rotations in the third year, the family planning rotation was the highest rated (4.70), was similar in value to a high-volume surgical rotation (4.51, P > .10) and the elective rotation (4.45, P >.05), and surpassed the average score for all inpatient rotations (4.00, P < .001), continuity clinic (4.10, P < .001), and outpatient clinical experiences (4.06, P <.01). According to residency graduates, the family planning rotation was rated 4.8 (where 5 indicates "far greater value" than other rotations), and 85% of respondents rated it of "maximum learning value". CONCLUSION: Obstetrics and gynecology residents place high value in the University of California, San Francisco PGY-3 family planning rotation during their training and in their first years of practice.     

分娩期综合性干预预防持续性枕后位的研究

目的研究产程不同时相干预预防持续性枕后位的措施，以降低持续性枕后位的发生率，改善分娩结局。方法将９６例枕后位产妇随机平均分为两组，对研究组的产妇施行针对产程不同时相的一系列干预措施，包括人工破膜、纠正异常胎轴、产妇采取与胎背同侧的高坡侧俯卧位、徒手扩张宫颈及徒手旋转胎头。结果研究组活跃期及第二产程较对照组短，研究组活跃期先露下降平均速度及宫口扩张平均速度均快于对照组，研究组的持续性枕后位发生率及胎儿窘迫发生率均低于对照组，产后出血量少于对照组（Ｐ＜０．０５）。结论综合性干预措施安全、有效、易行。