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.     

Elective induction vs. spontaneous labor associations and outcomes

OBJECTIVE: To determine factors and outcomes associated with elective medical induction of labor as compared with spontaneous labor in low-risk women. STUDY DESIGN: Using a birth certificate database including 11,849 low-risk, laboring women, univariate and multiple logistic regression was used to evaluate demographic and obstetric factors associated with elective labor induction. Low risk was defined as singleton, vertex, 37-41 weeks' gestation, no prior cesarean section, and no presenting medical/obstetric diagnoses considered indications for cesarean or induction. Adverse neonatal outcome was defined as 1- or 5-minute Apgar score < 7, neonatal intensive care unit admission or respiratory distress. Spontaneously laboring women (n = 10,608) were compared with women who underwent induced labor for no apparent medical/obstetric reason (n = 1,241). Interventions and outcomes during and after labor induction were adjusted for relevant associated variables. RESULTS: Odds ratios for epidural anesthesia, cesarean delivery and diagnoses of nonreassuring fetal heart rate patterns were independently increased following elective induction; odds ratios for cephalopelvic disproportion, instrumental delivery and adverse neonatal outcome were not. Maternal length of stay was 0.34 days longer with induction than with spontaneous labor (p < 0.0001). Slightly more induced labors ended before midnight. CONCLUSION: As compared with spontaneous labor, elective labor induction is independently associated with more intrapartum interventions, more cesarean deliveries and longer maternal length of stay. Neonatal outcome is unaffected.     

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.     

The impact of occiput posterior fetal head position on the risk of anal sphincter injury in forceps-assisted vaginal deliveries

OBJECTIVE: A forceps-assisted vaginal delivery is a well-recognized risk factor for anal sphincter injury. Some studies have shown that occiput posterior (OP) fetal head position is also associated with an increased risk for third- or fourth-degree lacerations. The objective of this study was to assess whether OP position confers an incrementally increased risk for anal sphincter injury above that present with forceps deliveries. STUDY DESIGN: This was a retrospective cohort study of 588 singleton, cephalic, forceps-assisted vaginal deliveries performed at our institution between January 1996 and October 2003. Maternal demographics, labor and delivery characteristics, and neonatal factors were examined. Statistical analysis consisted of univariate statistics, Student t test, chi2, and logistic regression. RESULTS: The prevalence of occiput anterior (OA) and OP positions was 88.4% and 11.6%, respectively. The groups were similar in age, marital status, body mass index, use of epidural, frequency of inductions, episiotomies, and shoulder dystocias. The OA group had a higher frequency of rotational forceps (16.2% vs 5.9%, P = .03), greater birth weights (3304 +/- 526 g vs 3092 +/- 777 g, P = .004), and a larger percentage of white women (48.8% vs 34.3%, P = .04). Overall, 35% of forceps deliveries resulted in a third- or fourth-degree laceration. Anal sphincter injury occurred significantly more often in the OP group compared with the OA group (51.5% vs 32.9%, P = .003), giving an odds ratio of 2.2 (CI: 1.3-3.6). In a logistic regression model that controlled for occiput posterior position, maternal body mass index, race, length of second stage, episiotomy, birth weight, and rotational forceps, OP head position was 3.1 (CI: 1.6-6.2) times more likely to be associated with anal sphincter injury than OA head position. CONCLUSION: Forceps-assisted vaginal deliveries have been associated with a greater risk for anal sphincter injury. Within this population of forceps deliveries, an OP position further increases the risk of third- or fourth-degree lacerations when compared with an OA position.     

Comparative study of induction of labor in nulliparous women with premature rupture of membranes at term compared to those with intact membranes: duration of labor and mode of delivery

AIM: To evaluate the effect of premature rupture of membranes (PROM) at term on the duration of labor and mode of delivery in comparison with intact membranes in nulliparous women with an unfavorable cervix whose labor was induced. METHODS: This retrospective cohort study included all term nulliparous women with an unfavorable cervix requiring labor induction over a 2-year period. Prostaglandin E(2) (dinoprostone) and oxytocin were used for labor induction. Criteria for enrolment included (i) singleton pregnancy; (ii) term nulliparous women; or (iii) Bishop score below 6. Statistics were analyzed with Student's t-test, chi(2)-test, Fisher's exact test, and multiple logistic regression. RESULTS: Our study subjects were 82 women whose labor was induced for PROM and 219 women with intact membranes whose labor was induced for social or fetal reasons. The mean durations of active phase of labor were not significantly different between women with PROM and those with intact membranes. However, the women with PROM had a significantly longer mean duration of second stage and a higher rate of cesarean delivery for failure to progress than those with intact membranes. Multiple logistic regression demonstrated that only PROM and fetal macrosomia were significantly associated with an increased risk of cesarean delivery for failure to progress after other confounding variables were adjusted. CONCLUSIONS: Labor induction for PROM at term in nulliparous women with an unfavorable cervix is associated with longer duration of the second stage and a higher risk of cesarean delivery for failure to progress in comparison to those with intact membranes.     

The indication for induction of labor impacts the risk of cesarean delivery

Objective: The risk of cesarean delivery following labor induction has been clearly established. While numerous factors are known to impact this risk, the indication for induction has rarely been examined as a risk factor. This study aimed to examine the relationship between indication for induction and ultimate mode of delivery after labor induction.

Methods: A retrospective cohort study was conducted examining all cases of labor induction in a tertiary center university teaching hospital over a one-year period. The primary outcome measure was mode of delivery (vaginal delivery versus cesarean delivery) and its relationship to the indication for induction. Secondary outcome measures were: parity, maternal age, birth week, cervical maturity, use of epidural anesthesia, fetal birth weight and fetal sex.

Results: Seven hundred and ninety-six women met inclusion criteria, of which 17.1% ultimately underwent cesarean delivery. Using multivariate analysis, fetal indications for induction (including intra-uterine growth restriction, oligohydramnios, placental abruption, macrosomia and post-term pregnancy) were found to significantly increase the risk of cesarean delivery in nulliparous women. The other significant factor was birth after week 40?+?0.

Conclusions: The indication for labor induction impacts the risk of cesarean delivery. Specifically, induction of labor for fetal indications significantly increases the risk of cesarean delivery in nulliparous women.     

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.     

Impact of labor induction,gestational age,and maternal age on cesarean delivery rates

OBJECTIVE: To quantify the impact of labor induction and maternal age on cesarean delivery rates in nulliparous and multiparous women between 36 and 42 weeks' gestation. METHODS: We performed a retrospective cohort study on 14,409 women delivering at two teaching hospitals in metropolitan Boston during 1998 and 1999. Women who had contraindications to labor, including a prior cesarean delivery, were excluded. The risks for cesarean delivery by induction status, gestational age by completed week between 36 and 42 weeks, maternal age <35, 35-39, and >/=40 years, and stratified by parity, were calculated by logistic regression. RESULTS: In nulliparas, labor induction was associated with an increase in cesarean delivery from 13.7% to 24.7% (adjusted odds ratio [OR] 1.70; 95% confidence interval [CI] 1.48, 1.95]). In multiparas, induction was associated with an increase from 2.4% to 4.5% (OR 1.49; 95% CI 1.10, 2.00). Other variables that placed a nulliparous woman at increased risk for cesarean delivery included maternal age of at least 35 years and gestational ages over 40 weeks. For multiparas, only maternal age 40 years or older and gestational age of 41 weeks were associated with an increase in cesarean deliveries. CONCLUSION: Induction of labor, older maternal age, and gestational age over 40 weeks each independently increase the risk for cesarean delivery in both nulliparous and multiparous women. Although the relative risk from induction is similar in nulliparas and multiparas, the absolute magnitude of the increase is much greater in nulliparas (11% versus 2.1%).     

Mode of delivery in pregnancies with suspected fetal growth restriction following induction of labor with vaginal prostaglandin E2

BACKGROUND: Many fetuses below the 10th percentile for gestational age are uncompromised. We aimed to evaluate the mode of delivery and immediate neonatal outcome in pregnancies with suspected fetal growth restriction (FGR) and normal antenatal assessment following induction of labor with vaginal application of prostaglandin E2 (PGE2). METHODS: Ninety women with suspected FGR (sonographic estimated fetal weight < 10th percentile) with normal oxytocin contraction test (OCT), biophysical profile (BPP) and reassuring fetal heart rate underwent induction of labor with vaginal application of PGE2 tablets. The findings were compared with 115 women admitted for induction of labor because of decreased fetal movement (group 2) and with 510 women with normal spontaneous onset of labor (group 3). RESULTS: There were no between-group differences in mean maternal age, gravidity, parity, nulliparity rate, number of tablets used or rate of patients receiving more than one PGE2 application. The rate of cesarean section (CS) in the study group (8.9%) was similar to the rate in groups 2 and 3 (14.8% and 9.0%, respectively). The incidence of nonreassuring fetal heart rate pattern leading to cesarean delivery was higher in the study group, but the rate of low 5-min Apgar scores (< 7) was similar in all groups. A logistic regression model and forward likelihood analysis yielded no single significant variable associated with increased risk of cesarean delivery. CONCLUSIONS: In selected cases of suspected FGR with reassuring fetal heart rate and normal OCT and BPP, induction of labor with vaginal PGE2 may yield a similar immediate fetal outcome and CS rate as in uncomplicated, induced or spontaneous deliveries.     

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.     

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.     

Bishop score and risk of cesarean delivery after induction of labor in nulliparous women

OBJECTIVE: To quantify the risk and risk factors for cesarean delivery associated with medical and elective induction of labor in nulliparous women. METHODS: A prospective cohort study was performed in nulliparous women at term with vertex singleton gestations who had labor induced at 2 obstetrical centers. Medical and elective indications and Bishop scores were recorded before labor induction. Obstetric and neonatal data were analyzed and compared with the results in women with a spontaneous onset of labor. Data were analyzed using univariate and multivariable regression modeling. RESULTS: A total of 1,389 women were included in the study. The cesarean delivery rate was 12.0% in women with a spontaneous onset of labor (n = 765), 23.4% in women undergoing labor induction for medical reasons (n = 435) (unadjusted odds ratio [OR] 2.24; 95% confidence interval [CI] 1.64-3.06), and 23.8% in women whose labor was electively induced (n = 189) (unadjusted OR 2.29; 95% CI 1.53-3.41). However, after adjusting for the Bishop score at admission, no significant differences in cesarean delivery rates were found among the 3 groups. A Bishop score of 5 or less was a predominant risk factor for a cesarean delivery in all 3 groups (adjusted OR 2.32; 95% CI 1.66-3.25). Other variables with significantly increased risk for cesarean delivery included maternal age of 30 years or older, body mass index of 31 or higher, use of epidural analgesia during the first stage of labor, and birth weight of 3,500 g or higher. In both induction groups, more newborns required neonatal care, more mothers needed a blood transfusion, and the maternal hospital stay was longer. CONCLUSION: Compared with spontaneous onset of labor, medical and elective induction of labor in nulliparous women at term with a single fetus in cephalic presentation is associated with an increased risk of cesarean delivery, predominantly related to an unfavorable Bishop score at admission. LEVEL OF EVIDENCE: II-2.     

Impact of abnormal results of outpatient fetal heart rate monitoring on maternal intervention in labor

OBJECTIVE: To conduct a retrospective, cohort study to determine the impact of abnormal outpatient fetal heart rate (FHR) testing on maternal interventions in labor, including labor induction, operative vaginal delivery and unplanned cesarean section. STUDY DESIGN: Our cohort consisted of 1,386 women with singleton gestations who had outpatient fetal nonstress testing within 1 week prior to giving birth etween 1993 and 1998. Antepartum FHR records were interpreted as reassuring or nonreassuring, and pregnancy records were abstracted for background medical information, labor interventions and pregnancy outcomes. Logistic regression models were used to describe the association between abnormal outpatient monitoring results and maternal interventions in labor. RESULTS: After adjusting for potential confounders (maternal age, race, prior history of cesarean section, antepartum indications for monitoring, fetal presentation and abnormal fetal heart rate patterns in labor), women with nonreassuring monitoring were 90% more likely to undergo induction. The 2 groups were similar in operative vaginal delivery rates, but pregnancies with nonreassuring testing were more than twice as likely to end with an unplanned cesarean section. CONCLUSION: Abnormal outpatient antenatal FHR testing may be independently associated with an increased risk of unplanned cesarean section.     

Epidural analgesia and fetal head malposition at vaginal delivery

OBJECTIVE: To determine if nulliparas who delivered with on-demand epidural analgesia are more likely to have malpositioning of the fetal vertex at delivery than women delivered during a period of restricted epidural use. METHODS: A retrospective cohort of nulliparous women with spontaneous labor delivered during a 12-month period immediately before the availability of on-demand labor epidural analgesia was compared with a similar group of nulliparas delivered after labor epidural analgesia was available on request. The primary outcome variable was a non-occiput anterior position or malpositioned fetal head at vaginal delivery. RESULTS: The frequency of epidural use increased from 0.9% before epidural analgesia became available on demand to 82.9% afterward. Fetal head malpositioning at vaginal delivery occurred in 26 of 434 (6.0%) women delivered in the before period compared with 29 of 511 (5.7%) in the after period (relative risk 0.95, 95% confidence interval 0.6, 1.6). No statistically significant difference in the incidence of fetal head malpositioning was present after patients were stratified by mode of delivery (Mantel-Haenszel weighted relative risk 0.94, 95% confidence interval 0.6, 1.4). The study sample size provided 85% power to detect a two-fold increase in the incidence of fetal malpositioning from a baseline rate of 6% associated with on-demand epidural use. CONCLUSION: Providing on-request labor epidural analgesia to nulliparas in spontaneous labor did not result in a clinically significant increase in the frequency of fetal head malpositioning at vaginal delivery.     

Induction of labor after one prior cesarean: predictors of vaginal delivery

OBJECTIVE: To estimate the characteristics most associated with vaginal birth in patients undergoing induction of labor after 1 prior cesarean delivery. METHODS: All patients who presented for induction of labor from 1996 to 2001 with a history of 1 prior cesarean delivery were identified. Relevant demographic and obstetric data were abstracted from the charts. Univariate analysis was used to identify predictive factors associated with vaginal birth after cesarean. Binary logistic regression was further used to identify which factors were independently associated with the outcome measure. RESULTS: Of the 429 women included in the study, 334 (77.9%) had a successful trial of labor. In the final binary logistic regression equation, prior vaginal delivery (odds ratio [OR] 3.75; 95% confidence interval [CI] 1.96, 7.18) remained independently associated with an increased chance of a vaginal delivery after a trial of labor. Conversely, prior cesarean delivery for dystocia (OR 0.46; 95% CI 0.27, 0.79), induction on or past the estimated date of delivery (OR 0.46; 95% CI 0.27, 0.78), need for cervical ripening (OR 0.35; 95% CI 0.20, 0.61), and maternal gestational or preexisting diabetes (OR 0.16; 95% CI 0.06, 0.40) were all factors associated with a decreased likelihood of achieving a successful trial of labor. CONCLUSION: Several factors are available which may assist in identifying patients with the best chance of vaginal delivery after an induction of labor in the presence of a prior low-transverse cesarean scar. LEVEL OF EVIDENCE: II-2     

Risk of cesarean delivery with elective induction of labor at term in nulliparous women.

OBJECTIVE: To quantify the risk of cesarean delivery associated with elective induction of labor in nulliparous women at term. METHODS: We performed a cohort study on a major urban obstetric service that serves predominantly private obstetric practices. All term, nulliparous women with vertex, singleton gestations who labored during an 8-month period (n = 1561) were divided into three groups: spontaneous labor, elective induction, and medical induction. The risk of cesarean delivery in the induction groups was determined using stepwise logistic regression to control for potential confounding factors. RESULTS: Women experiencing spontaneous labor had a 7.8% cesarean delivery rate, whereas women undergoing elective labor induction had a 17.5% cesarean delivery rate (adjusted odds ratio [OR] 1.89; 95% confidence interval [CI] 1.12, 3.18) and women undergoing medically indicated labor induction had a 17.7% cesarean delivery rate (OR 1.69; 95% CI 1.13, 2.54). Other variables that remained significant risk factors for cesarean delivery in the model included: epidural placement at less than 4 cm dilatation (OR 4.66; 95% CI 2.25, 9.66), epidural placement after 4 cm dilatation (OR 2.18; 95% CI 1.06, 4.48), chorioamnionitis (OR 4.61; 95% CI 2.89, 7.35), birth weight greater than 4000 g (OR 2.59; 95% CI 1.69, 3.97), maternal body mass index greater than 26 kg/m2 (OR 2.36; 95% CI 1.61, 3.47), Asian race (OR 2.35; 95% CI 1.04, 5.34), and magnesium sulfate use (OR 2.18; 95% CI 1.04, 4.55). CONCLUSION: Elective induction of labor is associated with a significantly increased risk of cesarean delivery in nulliparous women. Avoiding labor induction in settings of unproved benefit may aid efforts to reduce the primary cesarean delivery rate.     

Prediction of adverse outcome associated with vaginal misoprostol for labor induction

Objective: To identify predictors of adverse outcome in pregnant women at term receiving 50 μg of intravaginal misoprostol for labor induction. Study design: A prospective observational study was conducted of 720 pregnant women at term with an unfavorable cervix and a medical or obstetric indication for labor induction. All patients received 50 μg of intravaginal misoprostol every 4 h up to three doses. The primary outcome measure was “adverse outcome” defined as: neonatal death, fetal acidemia and emergent cesarean delivery performed for non-reassuring fetal heart rate tracings. A stepwise logistic regression analysis was used to identify predictors of adverse outcome. Results: Tachysystole (frequent uterine contractions) (odds ratio (OR), 3.7; 95% confidence interval (CI), 1.2–10.8) and fetal tachycardia (OR, 4.8; 95% CI, 1.4–16.2) were determined as significant predictors of adverse outcome. The specificity of the model was 94.2%, whereas the sensitivity was 20.4%. Conclusion: In the absence of tachysystole and fetal tachycardia, an uneventful delivery might be expected for women receiving 50 μg of intravaginal misoprostol.     

Induction of labor with prostaglandin E2 in women with previous cesarean section and unfavorable cervix

OBJECTIVE: To study the pregnancy outcome of induction of labor with prostaglandin E2 (PGE2) in women with one previous lower segment cesarean section. METHODS: A retrospective cohort design was used. The study sample included 1028 consecutive women with one previous cesarean section, of whom 97 underwent induction of labor (study group) and 931 were admitted with spontaneous onset of labor (control group). Vaginal tablets of PGE2 were used for cervical ripening in the study group. Mode of delivery, neonatal outcome, indications for cesarean section, and rate of uterine rupture were compared between the groups. RESULTS: There were no significant differences between the study and control groups in mean (+/-S.D.) maternal age (30.9 +/- 4.7 years versus 31.2 +/- 4.8 years, P = 0.6), gestational age at delivery (39.2 +/- 1.8 weeks versus 39.3 +/- 1.6 weeks, P = 0.36), overall rate of cesarean section (36% versus 37.3%, P = 0.8), rates of low 5-min Apgar score < or =7 (3.1% versus 3.7%, P = 0.67) or cesarean section performed for nonreassuring fetal heart rate (6.1% versus 3.1%, P = 0.1). There were four cases of uterine rupture, all in the control group compared to none in the study group (nonsignificant). CONCLUSION: The findings suggest that induction of labor in women with one previous cesarean section does not increase the risk of cesarean section rate and does not adversely affect immediate neonatal outcome. We cautiously suggest that when there is no absolute indication for repeated cesarean section, induction of labor may be considered.     

两种体侧卧位法纠正枕后位的临床观察

目的探讨产程中产妇采用两种不同体侧卧位纠正枕后位的临床效果.方法选择潜伏期经内诊或B超确诊为枕后位的初产妇100例,按随机表法分成同侧卧位组和对侧卧位组(各50例),分别采用同侧和对侧卧位法纠正胎方位,观察两组阴道分娩率、第1产程时间.结果(1)同侧卧位组阴道分娩34例(68%),胎儿转至枕前位27例(54%),对侧卧位组阴道分娩为22例(44%),胎儿转至枕前位12例(24%),两组比较,差异有显著性(P＜0.005).(2)同侧卧位组平均第1产程时间为(13.5±6.5)h;对侧卧位组平均第1产程时间为(17.1±7.2)h,两组比较,差异有极显著性(P＜0.01).结论产程中指导产妇取同侧卧位矫正枕后位,是提高阴道分娩率、缩短第1产程的有效方法.     

Is the management of epidural analgesia associated with an increased risk of cesarean delivery?

OBJECTIVE: The aim of this study was to quantify the association of cesarean delivery with epidural analgesia management, specifically with the timing of epidural catheter placement in relation to labor, the type of epidural analgesia, and the use of bolus dosing.Study Design: A retrospective cohort design was used to investigate 1561 consecutive nulliparous parturients whose labor occurred between November 1, 1996, and June 30, 1997, at Northwestern Memorial Hospital and who were delivered of term, singleton neonates in a cephalic presentation. The relationship between the management of epidural analgesia and the risk for cesarean delivery was determined with stepwise logistic regression to control for potential confounding variables. RESULTS: There was a significantly increased risk of cesarean delivery associated with decrements in cervical effacement (P =.001), cervical dilatation (P =.001), and fetal station (P =.001) at the time of epidural catheter placement. An increasing number of epidural boluses during the first stage of labor was also associated with increased risk of cesarean delivery (P =.001). After we controlled for maternal age, maternal body mass index, gestational age, infant birth weight, induction of labor, use of magnesium sulfate, and presence of chorioamnionitis, the adjusted odds of cesarean delivery associated with fetal station (odds ratio, 1.45; 95% confidence interval, 1.2-1.7) and epidural boluses (odds ratio, 1.55; 95% confidence interval, 1.3-1.8) during the first stage of labor remained significant. CONCLUSION: The management of epidural analgesia during labor was associated with the potential for increased risk of cesarean delivery. This risk increased with higher stations of the fetal head at the time of epidural catheter placement and with more frequent epidural boluses of local anesthetic during the first stage of labor.