Obstetrical parameters influencing the duration of the second stage of labor

Three-dimensional ultrasound assessment of risk factors for cystocele and Green classification in primipara

BACKGROUND AND AIMS

The present study aimed to analyze the effects of factors on cystocele and the Green classification.

MATERIALS AND METHODS

We conducted a cross-sectional study on 357 primiparous women examined at our hospital from January 2019 to May 2021. The following data were recorded: maternal characteristics, neonatal characteristics, and factors of childbirth. It was added to the multivariate logistic regression model to determine the independent predictors of the cystocele and the Green classification.

RESULTS

A total of 242 women had cystocele, including 71 women with Green type I cystocele, 134 women with Green type II cystocele, and 37 women with Green type III cystocele. In multivariate logistic regression analysis, body mass index (BMI) at delivery was associated with cystocele, while BMI at delivery and the second stage of labor (SSL) > 1 h were independently with the distance from the symphysis pubis to the bladder neck (SPBN) abnormal (P < 0.05). BMI at examination was associated with the large retrovesical angle (RVA) (P < 0.05). BMI at delivery and the fetal right occiput anterior position (ROA) were independently associated with the distance from the symphysis pubis to the posterior wall of the bladder (SPBP) abnormal (P < 0.05), while epidural anesthesia (EDA) was the protective factor (P < 0.05).

CONCLUSION

Primipara women should strive to avoid exposure to modifiable risk factors such as controlling weight during pregnancy, reducing weight after delivery, and shortening SSL to reduce the occurrence of cystocele.

Duration of second stage of labor and factors associated with prolonged second stage: A national population-based study in France

OBJECTIVES

Prolonged second stage of labor could be associated with an increase in maternal and neonatal morbidity. However, in France, no consensual definition of prolonged 2nd stage of labor exists and therefore factors associated with prolonged second stage have not yet been studied. From national population-based data, we aimed at defining the prolonged 2nd stage of labor in France and identifying its associated factors for women with epidural.

STUDY DESIGN

From the French national perinatal survey of 2016, we included all women who reached 2nd stage of labor and delivered at term of a singleton infant in cephalic presentation. We studied the distribution of the duration of the 2nd stage according to parity and defined prolonged 2nd stage as the 90th percentile. Among women with epidural, factors associated with a prolonged 2nd stage of labor were then explored by univariate and multilevel multivariable analysis, to take the cluster effect into account. The proportional change of variance was estimated for each multivariate model.

RESULTS

Among the 8154 women included, 3574 were nulliparous and 4580 multiparous. Prolonged second stage was defined as a duration of more than 89.6 min and 30.6 min for nulliparous and multiparous women without epidural; and respectively 185.7 min and 120.1 min for women with epidural analgesia. The factors associated with prolonged 2nd stage of labor were respectively for nulliparous and multiparous women, macrosomia (aOR 1.74 [1.03-2.94] and ORa 2.52 [1.69-3.76]), prenatal preparation classes (aOR 1.47 [1.04-2.08] and aOR 1.56 [1.21-2.01]), a prolonged 1st stage (aOR 1.47 [1.14-1.87] and aOR 1.52 [1.19-1.95]) and delivery in a public maternity unit (aOR 2.68 [1.50-4.78] and aOR 3.12 [1.88-5.17]). Women's characteristics accounted for 3.4% of the variance and maternity organizational characteristics for 26.1%.

CONCLUSION

In France, prolonged 2nd stage of labor can be defined as a 2nd stage exceeding 3 h in nulliparous and 2 h in multiparous women with epidural analgesia. The identification of its associated factors allows determining a target population of women at risk of prolonged 2nd stage and improve their 2nd stage's management.

Obesity, Second Stage Duration, and Labor Outcomes in Nulliparous Women

OBJECTIVE

This study aimed to estimate second stage duration and its effects on labor outcomes in obese versus nonobese nulliparous women.

STUDY DESIGN

This was a secondary analysis of a cohort of nulliparous women who presented for labor at term and reached complete cervical dilation. Adjusted relative risks (aRR) were used to estimate the association between obesity and second stage characteristics, composite neonatal morbidity, and composite maternal morbidity. Effect modification of prolonged second stage on the association between obesity and morbidity was assessed by including an interaction term in the regression model.

RESULTS

Compared with nonobese, obese women were more likely to have a prolonged second stage (aRR: 1.48, 95% CI: 1.18-1.85 for ≥3 hours; aRR: 1.65, 95% CI: 1.18-2.30 for ≥4 hours). Obesity was associated with a higher rate of second stage cesarean (aRR: 1.78, 95% CI: 1.34-2.34) and cesarean delivery for fetal distress (aRR: 2.67, 95% CI: 1.18-3.58). Obesity was also associated with increased rates of neonatal (aRR: 1.38, 95% CI: 1.05-1.80), but not maternal morbidity (aRR: 1.06, 95% CI: 0.90-1.25). Neonatal morbidity risk was not modified by prolonged second stage.

CONCLUSION

Obesity is associated with increased risk of neonatal morbidity, which is not modified by prolonged second stage of labor.

Induction of labor, and physiological and psychological stress responses as expressed by salivary cortisol: a prospective study

PURPOSE

To describe patterns of physiological and psychological stress during induced labor and their correlation to obstetrical and neonatal outcomes.

METHODS

This prospective, observational study included 167 women, with low-risk, singleton pregnancies, who delivered at term, at a tertiary academic center from 2015 through 2018. Among them, 72 (43%) underwent induction and 95 (57%) had spontaneous labor onset. Physiological stress was evaluated by salivary cortisol measurements and emotional stress by questionnaires (visual analogue stress scale 0-10) during latent phase, active phase and full dilation stages of labor, as well as 2 min and 2 h postpartum. Cord blood cortisol and pH were obtained. Stress patterns were compared between parturients who did or did not undergo induction. Modes of delivery, labor and delivery complications, and early neonatal outcomes were compared. Mothers completed the Hospital Anxiety and Depression Scale.

RESULTS

Induced women had lower cortisol concentrations during the latent phase compared to spontaneous onset of labor (p = 0.003), with no differences during active (p = 0.237), full dilation (0.668), 2 min and 2 h after delivery (p = 0.666). Stress scale and Hospital Anxiety and Depression Scale scores were similar between groups. Cord cortisol (p = 0.294), 1-min Apgar score ≤ 7 (p = 0.502) and 5-min Apgar score ≤ 7 (p = 0.37) were similar. All had cord pH > 7.

CONCLUSIONS

Induction does not increase stress during labor. Moreover, it might have a positive effect on reducing cortisol during the latent phase. These findings might reassure women who are concerned about induction of labor.

Pushing the limits: perinatal outcomes beyond prolonged second stage

Objective: To evaluate whether extremely prolonged second stage of labor in nulliparous women affects mode of delivery and perinatal outcomes.Methods: We performed a retrospective cohort study of nulliparous women with singleton gestations and cephalic presentation who reached 10 cm of cervical dilation at gestational age 36 0/7-41 6/7. Women were stratified by epidural status. Deliveries were compared by length of second stage: 0-179 min (normal second stage, NSS), 180-299 min (prolonged second stage, PSS), and ≥300 min (extremely prolonged second stage, EPSS). Primary outcome was incidence of vaginal delivery. Secondary outcomes were maternal and neonatal morbidities.Results: Six hundred sixty-one women were evaluated; overall, 92.7% (613/661) of the patients delivered vaginally, with 84.6% (559/661) of women undergoing spontaneous vaginal delivery. In women with epidural anesthesia, 90.6% (446/492) delivered vaginally (97.2% of NSS, 95.1% of PSS, and 69.2% of EPSS). In women without epidural anesthesia, 98.8% (167/169) delivered vaginally (99.3% of NSS, 100.0% of PSS, and 87.5% of EPSS). Women with epidural anesthesia and EPSS had a higher rate of postpartum hemorrhage (aOR: 8.52; 95% CI: 3.99-18.19) and third-degree laceration when compared to NSS (aOR: 5.87; 95% CI: 1.71-20.17). EPSS neonates had a higher rate of CPAP use (OR: 3.99; 95% CI: 1.82-8.74) and significantly higher birth weight (p < .0001) and composite neonatal outcomes (OR: 4.98; 95% CI: 2.34-10.59) compared to NSS.Conclusion: In nulliparous women at term with singleton gestations who reached second stage, the chance of vaginal delivery was 92.7%; even after 5 h of second stage, most women delivered via vaginal delivery (70.4%, 81/115). In those with epidural anesthesia, the PSS group had similar perinatal outcomes as the NSS group, whereas the EPSS group had significantly worse perinatal outcomes. Second stage ≥5 h is a potential tipping point for hazardous perinatal outcomes.

The impact of epidural analgesia on the duration of the second stage of labor

BACKGROUND

We aimed to describe the length of second stage of labor in a contemporary cohort. We calculated the 5th, 50th, and 95th percentiles for second-stage length stratified by parity and epidural analgesia use and evaluated the effect of labor induction and oxytocin augmentation in our cohort.

METHODS

We did a retrospective analysis of all live, singleton, term vaginal deliveries in one tertiary hospital. Multivariate linear regression was used to evaluate second-stage duration confounders. First, we calculated the second-stage length and presented it as 5th, 50th, and 95th percentiles stratified by epidural analgesia and parity. Second, we evaluated the effect of labor induction and oxytocin augmentation on second-stage length, and third, we determined the demographic and obstetrical confounders that affected second-stage length.

RESULTS

Overall, 15 500 deliveries were included. Nulliparity, oxytocin augmentation, epidural use, birthweight, labor induction, lower body mass index, and higher maternal age were found to be significantly associated with prolongation of the second stage. Epidural use was associated with an additional 82 minutes for the 95th percentile for both nulliparas and multiparas and tripled the rate of prolonged second stage for the entire cohort. Labor induction was associated with clinically significant prolongation of the second stage in nulliparas with epidural analgesia only. Oxytocin was associated with longer duration of the second stage for nulliparas, regardless of epidural use.

DISCUSSION

Our findings suggest a significant prolongation of the second stage in women receiving epidural analgesia. Recommendations for management of second stage should be reconsidered by contemporary data.

Impact factors on fetal descent rates in the active phase of labor: a retrospective cohort study

AIM

To assess fetal descent rates of nulliparous and multiparous women in the active phase of labor and to evaluate significant impact factors.

METHODS

In a retrospective cohort study at the University Hospital of Zurich, Switzerland, we evaluated 6045 spontaneous vaginal deliveries with a singleton in vertex presentation between January 2007 and July 2014 at 34 0/7 to 42 0/7 gestational weeks. Median fetal descent rates and their 10th and 90th percentiles were assessed in the active phase of labor and different impact factors were evaluated.

RESULTS

Fetal descent rates are exponentially increasing. Nulliparous women have slower fetal descent than multiparous women (P<0.001), ranging from 0 to 5.81 cm/h and from 0 to 15 cm/h, respectively. The total duration of fetal descent in labor is 5.42 h for nulliparous and 2.71 h for multiparous women. Accelerating impact factors are a lower fetal station, multiparity, increasing maternal weight and fetal occipitoanterior position, whereas epidural anesthesia decelerates fetal descent (P<0.001).

CONCLUSIONS

Fetal descent is a hyperbolic increasing process with faster descent in multiparous women compared to nulliparous women, is highly inter individual and is associated with different impact factors. The diagnosis of labor arrest or prolonged labor should therefore be based on such rates as well as on individual evaluation of every parturient.

[Childbirth among primiparous women in Lubumbashi: maternal and perinatal prognosis]

INTRODUCTION

Childbirth in primiparous women is associated with many complications and, therefore, primiparous women are considered high risk due to maternal and fetal concerns. This study aims to determine birth rate in primiparous women in our environment, to identify factors associated with delivery by cesarean section and to assess maternal and perinatal morbi-mortality from childbirth in primiparous women living in Lubumbashi.

METHODS

We conducted a cross-sectional, analytical study of singleton births in 10 referral maternity hospitals in Lubumbashi over the period December 2013-May 2014. Primiparous births were compared to multiparous births. Maternal sociodemographic parameters as well as maternal and perinatal morbi-mortality were analyzed. The odds ratio and its confidence interval were calculated. Threshold significance level was set at p < 0.05.

RESULTS

Primiparity rate was 19.9%. Compared to multiparous births, primiparous births were mainly observed in adolescents (OR=11. 27, (7.98-15.91)), in students (OR = 5.61 (3.33-9.45)) and in women living alone (OR=7.62 (4.36-13.30)). Risk factors associated with delivery by cesarean section in primiparous women included obstetric evacuation (OR = 9.69 (4.75-19.74)), the lack of prenatal monitoring (OR=2.57, (1.32-5.01)), size ≤ 150 cm (OR = 2.42 (1.04-5.65)), uterine height > 34 cm (OR = 2.33 (1.32-4.10)) and malpresentation (OR = 6.37 (2.92-13.87)). With regard to maternal prognosis, we observed that high blood pressure (OR = 1.91 (1.32-2.74)), malpresentation (OR = 1.95 (1.16-3.17)), oxytocin use (OR = 2.03 (1.64-2.52)), cesarean section (OR = 2.04 (1.47-2.83)), episiotomy (OR=11.89 (8.61-16.43)) and eclampsia (OR = 4.21 (1.55-11.44)) were significantly associated with primiparity. The rates of low 5th minute Apgar score (OR = 1.55 (1.03-2.32)) and of deaths occurred during early neonatal period (OR=1.80 (1.08-2.98)) were significantly higher in primiparous women than in multiparous women.

CONCLUSION

This study shows that primiparous birth is a problem in Lubumbashi. Hence improvement in mother-child care during primiparous childbirth includes the development of protocols for adequate management of childbirths.

Durations of second stage of labor and pushing, and adverse neonatal outcomes: a population-based cohort study

OBJECTIVE

The associations between duration of second stage of labor, pushing time and risk of adverse neonatal outcomes are not fully established. Therefore, we aimed to examine such relationships.

STUDY DESIGN

A population-based cohort study including 42 539 nulliparous women with singleton infants born in cephalic presentation at ⩾37 gestational weeks, using the Stockholm-Gotland Obstetric Cohort, Sweden, and the Swedish Neonatal Quality Register, 2008 to 2013. Poisson regression was used to analyze estimated adjusted relative risks (RRs), with 95% confidence intervals (CIs). Outcome measures were umbilical artery acidosis (pH <7.05 and base excess <-12), birth asphyxia-related complications (including any of the following conditions: hypoxic ischemic encephalopathy, hypothermia treatment, neonatal seizures, meconium aspiration syndrome or advanced resuscitation after birth) and admission to neonatal intensive care unit (NICU).

RESULTS

Overall rates of umbilical artery acidosis, birth asphyxia-related complications and admission to NICU were 1.08, 0.63 and 6.42%, respectively. Rate of birth asphyxia-related complications gradually increased with duration of second stage: from 0.42% at <1 h to 1.29% at ≥4 h (adjusted RR 2.46 (95% CI 1.66 to 3.66)). For admission to NICU, corresponding rates were 4.97 and 9.45%, and adjusted RR (95% CI) was 1.80 (95% CI 1.58 to 2.04). Compared with duration of pushing <15 min, a duration of pushing ⩾60 min increased rates of acidosis from 0.57 to 1.69% (adjusted RR 2.55 (95% CI 1.51 to 4.30)).

CONCLUSION

Prolonged durations of second stage of labor and pushing are associated with increased RRs of adverse neonatal outcomes. Clinical assessment of fetal well-being is essential when durations of second stage and pushing increases.

Are freestanding midwifery units a safe alternative to obstetric units for low-risk, primiparous childbirth? An analysis of effect differences by parity in a matched cohort study

Background

Intrapartum complications and the use of obstetric interventions are more common in primiparous childbirth than in multiparous childbirth, leading to concern about out of hospital birth for primiparous women. The purpose of this study was to determine whether the effect of birthplace on perinatal and maternal morbidity and the use of obstetric interventions differed by parity among low-risk women intending to give birth in a freestanding midwifery unit or in an obstetric unit in the North Denmark Region.

Methods

The study is a secondary analysis of data from a matched cohort study including 839 low-risk women intending birth in a freestanding midwifery unit (primary participants) and 839 low-risk women intending birth in an obstetric unit (individually matched control group). Analysis was by intention-to-treat. Conditional logistic regression analysis was applied to compute odds ratios and effect ratios with 95% confidence intervals for matched pairs stratified by parity.

Results

On no outcome did the effect of birthplace differ significantly between primiparous and multiparous women. Compared with their counterparts intending birth in an obstetric unit, both primiparous and multiparous women intending birth in a freestanding midwifery unit were significantly more likely to have an uncomplicated, spontaneous birth with good outcomes for mother and infant and less likely to require caesarean section, instrumental delivery, augmented labour or epidural analgesia (although for caesarean section this trend did not attain statistical significance for multiparous women). Perinatal outcomes were comparable between the two birth settings irrespective of parity. Compared to multiparas, transfer rates were substantially higher for primiparas, but fell over time while rates for multiparas remained stable.

Conclusions

Freestanding midwifery units appear to confer significant advantages over obstetric units to both primiparous and multiparous mothers, while their infants are equally safe in both settings. Our findings thus support the provision of care in freestanding midwifery units as an alternative to care in obstetric units for all low-risk women regardless of parity. In view of the global rise in caesarean section rates, we consider it an important finding that freestanding midwifery units show potential for reducing first-birth caesarean.

Electronic supplementary material

The online version of this article (doi:10.1186/s12884-016-1208-1) contains supplementary material, which is available to authorized users.

Predictors of labor abnormalities in university hospital: unmatched case control study

Background

Abnormal labor is one of the common emergency obstetric problems contributing for more than two-thirds of the unplanned cesarean section. In Ethiopia, although labor abnormality and its complications like obstetric fistula are highly prevalent, there is no published study that determines the predictors of labor abnormalities.

Methods

The study design was an unmatched case control which included 844 women (408 cases and 436 controls). Cases were identified when a woman was diagnosed to have one of the labor abnormalities at term (prolonged latent stage, active phase disorder, prolonged second stage, descent disorder and obstructed labor). Subgroup logistic regression analyses were done taking the different type of labor abnormalities as the dependent variable.

Results

Nearly half of the cases (48.6%) were found to have the active phase disorder. Obstructed labor alone accounted for about 16.8% of the cases. The mean gestational age of cases and controls was almost comparable. More than a quarter of cases and controls came to the hospital in the second stage of labor. More than two-thirds of the cases (67.4%) gave birth by cesarean section. The logistic regression analysis demonstrated an independent association of overall labor abnormality with pelvic inadequacy. The subgroup analysis, however, revealed that several obstetric factors were associated with one or more types of labor abnormalities.

Conclusion

Active phase disorders were the commonest type of labor abnormalities. Cases were late in reporting to the hospital. Malposition, inadequate pelvis and inadequate uterine contraction were some of the predictors of specific types of labor abnormalities.

The timing of amniotomy, oxytocin and neuraxial analgesia and its association with labour duration and mode of birth

PURPOSE

The objective was to study the association of different timings of intrapartum interventions with labour duration and mode of birth.

METHODS

A longitudinal cohort study of 2,090 nulliparae and 1,873 multiparae with a singleton in cephalic presentation was conducted. We assessed the association between, on the one hand, the timing of augmentation with oxytocin, neuraxial analgesia and amniotomy, and, on the other hand, the time to complete dilatation, spontaneous or operative vaginal delivery or caesarean delivery, using a Cox regression model accounting for standard confounders.

RESULTS

From amniotomy onwards labour was accelerated. In multiparae, amniotomy was associated with an initial 6.6-fold acceleration, decreasing first stage duration until the hazard ratio reached around 3.5, where the intervention was performed 5 h after labour onset; thereafter, acceleration continued with a hazard ratio of around 3. In nulliparae, neuraxial analgesia was associated with a shorter first stage when administered between 7 and 11 h after labour onset; the later it was performed, the less likely was spontaneous birth and the more likely an operative vaginal birth in nulliparae or a caesarean section in multiparae. The start of oxytocin augmentation was associated with acceleration towards both full dilatation and caesarean section during first stage and an increased risk of operative vaginal birth during second stage. The later oxytocin augmentation started, the more likely it was that spontaneous birth would be retarded in multiparous women.

CONCLUSIONS

Applying amniotomy, oxytocin and neuraxial analgesia at their optimal timing may improve the progress and outcome of labour.

Intrapartum considerations in prenatal care

The epidemic of obesity continues to grow undaunted, promising to affect the lives of more women of childbearing age. The challenges facing those charged with obstetrical care of the obese may require variation in care from forethought and planning, to consultation or referral for care at specialized centers. The routine management of late pregnancy must take into account the increase in risk for late fetal loss, failed induction and trial of labor after cesarean delivery, and postcesarean complications, such as wound-related morbidity and venous thromboembolism. Awareness of prolonged labor curves and the risk of shoulder dystocia must also be part of the management of labor. The data regarding many interventions attempted on behalf of these at risk gravidas are rudimentary but may allow for modifications in care that will positively impact outcomes for mother and child.

The frequency of meconium-stained amniotic fluid increases as a function of the duration of labor

OBJECTIVE

The purpose of this study was to determine whether there is a relationship between the frequency of meconium-stained amniotic fluid (MSAF) and the duration of labor in term singleton gestation.

METHODS

The clinical characteristics of women who delivered term singleton live newborns between 2001 and 2006 were examined. The cases involving neonates with major congenital anomalies were excluded.

RESULTS

(1) The frequency of MSAF in term pregnancies was 18.4% (806/4376); (2) MSAF was found in only 2.8% (28/1008) of women who delivered by elective cesarean, but in 23.1% (778/3368) of women who delivered after the onset of labor (p < 0.001); (3) The longer the duration of labor (first stage, second stage, or total), the higher the frequency of MSAF (p < 0.001 for each); this remained significant after adjusting for other confounding variables such as parity, duration of rupture of membranes, gestational age at delivery, and mode of delivery (p < 0.001 for each).

CONCLUSION

MSAF was found in only 2.8% (28/1008) of women who delivered before the onset of labor, but in 23.1% (778/3368) of women who delivered after the onset of labor. The longer the duration of labor, the higher the risk of MSAF in term singleton gestation.

A multi-centre cohort study shows no association between experienced violence and labour dystocia in nulliparous women at term

BACKGROUND

Although both labour dystocia and domestic violence during pregnancy are associated with adverse maternal and fetal outcome, evidence in support of a possible association between experiences of domestic violence and labour dystocia is sparse. The aim of this study was to investigate whether self-reported history of violence or experienced violence during pregnancy is associated with increased risk of labour dystocia in nulliparous women at term.

METHODS

A population-based multi-centre cohort study. A self-administrated questionnaire collected at 37 weeks of gestation from nine obstetric departments in Denmark. The total cohort comprised 2652 nulliparous women, among whom 985 (37.1%) met the protocol criteria for dystocia.

RESULTS

Among the total cohort, 940 (35.4%) women reported experience of violence, and among these, 66 (2.5%) women reported exposure to violence during their first pregnancy. Further, 39.5% (n = 26) of those had never been exposed to violence before. Univariate logistic regression analysis showed no association between history of violence or experienced violence during pregnancy and labour dystocia at term, crude OR 0.91, 95% CI (0.77-1.08), OR 0.90, 95% CI (0.54-1.50), respectively. However, violence exposed women consuming alcoholic beverages during late pregnancy had increased odds of labour dystocia, crude OR 1.45, 95% CI (1.07-1.96).

CONCLUSIONS

Our findings indicate that nulliparous women who have a history of violence or experienced violence during pregnancy do not appear to have a higher risk of labour dystocia at term, according to the definition of labour dystocia in this study. Additional research on this topic would be beneficial, including further evaluation of the criteria for labour dystocia.

Intrapartum risk factors for levator trauma

OBJECTIVE

To determine intrapartum risk factors associated with levator trauma as identified by ultrasound imaging.

DESIGN

A prospective observational study.

SETTING

Antenatal clinic of a tertiary hospital between May 2005 and February 2008.

POPULATION

Nulliparous women (n=488) in their first ongoing pregnancy.

METHODS

An interview and four-dimensional translabial ultrasound was carried out between 36 and 38 weeks and again 3-4 months after delivery. Obstetric data were collected from the hospital database and/or participants' records.

MAIN OUTCOME MEASURES

Levator macrotrauma ('avulsion') and microtrauma (irreversible overdistension).

RESULTS

A total of 367 women (75%) returned for the postpartum assessment after normal vaginal delivery (n=187, 51%), vacuum (n=34, 9%), forceps (n=20, 5%) and caesarean section (n=126, 34%). Median follow up was 4.08 months (interquartile range 3.68-5.03 months). Levator avulsion was diagnosed in 32 (13%) of the women who delivered vaginally and in none of the caesarean section group regardless of indication. On multivariable regression forceps delivery was significantly associated with avulsion (P=0.01; OR 3.83; 95% CI 1.34-10.94). Using >20% peripartum increase in hiatal area on Valsalva as the cutoff, 28.5% of vaginally parous women were shown to have suffered irreversible overdistension. This was positively associated with the length of second stage (P=0.001; OR 1.01 per minute; 95% CI 1.0-1.02). Intrapartum epidural appeared to have a protective effect (P=0.03; OR 0.42; 95% CI 0.19-0.93).

CONCLUSION

Levator trauma at the time of first delivery is associated with vaginal delivery, forceps and a longer second stage. Epidural pain relief may exert a protective effect.

Biomechanical analyses of the efficacy of patterns of maternal effort on second-stage progress

OBJECTIVE

To develop and use a biomechanical computer model to simulate the effect of varying the timing of voluntary maternal pushes during uterine contraction on second-stage labor duration.

METHODS

Published initial pelvic floor geometry was imported into technical computing software to build a simplified three-dimensional biomechanical model with six representative viscoelastic levator muscle bands interconnected by a hyperelastic iliococcygeal raphe. An incompressible sphere simulated the molded fetal head. Forces from uterine contraction and voluntary expulsive efforts were summed to push the model fetal head along the curve of Carus opposed by the resistance of the pelvic floor structures to stretch. Holding uterine maximal contraction force and push strength constant, pushes were timed before ("pre"), at ("peak"), and after ("post") maximal uterine contraction force. The effect of different combinations of pushes on second stage duration and the number of pushes required for delivery were evaluated.

RESULTS

Calculated second stage durations ranged from 57.5 minutes (triple or pre-peak-post pattern) to 75.8 minutes (prepush and postpush patterns). Delivery with the triple-push pattern required 59 voluntary pushes, while the peak-push pattern required 23 voluntary pushes, a 61% reduction. The corresponding reduction for the pre-and-peak-push pattern was 29%, the peak-and-post push pattern was 30%, the prepush pattern was 54%, and the postpush pattern was 56%.

CONCLUSION

Although the triple-push pattern resulted in a 16% shorter second stage, this came at the energetic expense of a 61% increase in the number of pushes required.

LEVEL OF EVIDENCE

III.

Obstetric risk indicators for labour dystocia in nulliparous women: a multi-centre cohort study

BACKGROUND

In nulliparous women dystocia is the most common obstetric problem and its etiology is largely unknown. The frequency of augmentation and cesarean delivery related to dystocia is high although it is not clear if a slow progress justifies the interventions. Studies of risk factors for dystocia often do not provide diagnostic criteria for the diagnosis. The aim of the present study was to identify obstetric and clinical risk indicators of dystocia defined by strict and explicit criteria.

METHODS

A multi-centre population based cohort study with prospectively collected data from 2810 nulliparous women in term spontaneous labour with a singleton infant in cephalic presentation. Data were collected by self-administered questionnaires and clinical data-records. Logistic regression analyses were used to estimate adjusted Odds Ratios (OR) and 95% confidence intervals (CI) are given.

RESULTS

The following characteristics, present at admission to hospital, were associated with dystocia during labour (OR, 95% CI): dilatation of cervix < 4 cm (1.63, 1.38-1.92), tense cervix (1.31, 1.04-1.65), thick lower segment (1.32, 1.09-1.61), fetal head above the inter-spinal diameter (2.29, 1.80-2.92) and poor fetal head-to-cervix contact (1.83, 1.31-2.56). The use of epidural analgesia (5.65, 4.33-7.38) was also associated with dystocia.

CONCLUSION

Vaginal examinations at admission provide useful information on risk indicators for dystocia. The strongest risk indicator was use of epidural analgesia and if part of that is causal, it is of concern.

[Length of pushing efforts: pushing is not playing. Reply to the article of C. Le Ray and F. Audibert]

The aim of this work is to answer constructively to C. Le Ray and F. Audibert who were surprised that the French guidelines recommended an assisted delivery after 30 min pushing, even if the fetal heart rate is reassuring. We first resumed the definition of "second stage of labor", this word including the first phase with no pushing efforts and the second phase with active pushing of the mother. With that definition, the length of the second stage is around 60 min for the primipara and 20 min for the multipara, this length being modified by the use of peridural. We then specified the physiological mechanisms influencing the acidobasic equilibrium during the pushing time. Those mechanisms are difficult to consider because foetal heart rate monitoring is often "lost" during that phase. Altogether, these factors bring incertitude about progressive foetal acidosis and incapacity to diagnose it. Finally, the literature analysis teaches us that increasing the second stage of labor (inactive plus active phases) during the normal pregnancy seems to be at low risk for the foetus within the primiparas, but display a risk for the mother and so might be limited. Comparing the delayed pushing with the immediate pushing only lead us to conclude that delayed pushing is dangerous, as is prolonged second stage. In conclusion, we think that prolonging the second stage of labor is possible but must be by increasing the inactive first phase of the second stage, especially as long as we will not get a noninvasive and reliable method allowing assessing the well-being of the foetus.

[How long can we wait at full dilatation. A study of maternal and neonatal morbidity related to the duration of the second stage of labour in nulliparous women]

OBJECTIVES

To determine the statistical association, in nulliparous patients, between maternal and fetal morbidity and the length of the second stage of labour. To precise whether a prolongation of this period of more than 2h may results in a dramatic increase of this morbidity.

MATERIALS AND METHODS

Retrospective cohort study conducted in a level III referral centre between 1 April 2004 and 30 April 2005, including all nulliparous, term, cephalic, live singleton birth without fetal malformation in patients reaching the second stage of labour (n=1191). All deliveries were performed without restrictions in the length of the second stage of labour in the absence of fetal heart rate abnormalities. Maternal and neonatal morbidity were examined according to the duration of the second stage of labour with univariate analysis and after statistical adjustment with multivariate logistic regression for potential confounding variables.

RESULTS

Global maternal morbidity ranged from 5.7% after 1h to 20.4% after more than 3h of full cervical dilatation. After a second stage duration of 2h, each additional completed hour resulted in a significant increase in global maternal morbidity (OR 1.78; IC 95% [1.59-1.97]), postpartum haemorrhage (OR 1.72; IC 95% [1.21-2.23]) and level three or four perineal lacerations (OR 1.24; IC 95% [1.7-1.41]). In the same time, caesarean section rate (OR 2.09; IC 95% [1.84-2.34]) and operative vaginal deliveries (OR 1.82; IC 95% [1.59-2.05]) increased significantly. Conversely, our study didn't demonstrate any significant association between neonatal morbidity and the length of the second stage of labour.

CONCLUSION

Our study confirmed the association between the duration of the second stage of labour and the increase of maternal but not neonatal morbidity. Such an association, predominantly after 3h spend at full cervical dilatation, needs to be taken into account and, according to our experience, may justify caesarean section.

Maternal Age and the Duration of the Second Stage of Labor

The purpose of this study was to investigate the relationship between parity, maternal age at delivery, gestational age, and duration of the second stage of labor. In this article a retrospective analysis of deliveries during the period from 2000 to 2005 in our Institution was made. We recorded 208 pregnant women under the age of 20 years, 6,115 between 20 and 40 years, and 188 over the age of 40 years considering parity, duration of second stage of labor, birth weight, and gestation age. The correlation of the above parameters was statistically analyzed. In primigravidas, under the age of 20 years, the second stage of labor was significantly shorter compared to women aged over 40 years, and significantly shorter compared to women between the age of 20 and 40 years. Gestational age at delivery was significantly shorter in women aged over 40 years compared to those under the age of 20 years as well as to those between 20 and 40 years of age. Age was positively correlated to the duration of the second stage of labor and negatively correlated to the gestation age at delivery. In multigravidas, age was negatively correlated to the gestational age at delivery. In primigravidas, maternal age was positively correlated with the duration of the second stage of labor. On the contrary, gestational age at delivery was negatively correlated with maternal age. In multigravidas, a negative correlation between maternal age and gestational age at delivery was statistically significant.

Prolonged second stage of labor and risk of adverse maternal and perinatal outcomes: a systematic review

BACKGROUND

Safe and effective management of the second stage of labor presents a clinical challenge for laboring women and practitioners of obstetric care. This systematic review was conducted to evaluate evidence for the influence of prolonged second stage of labor on the risk of selected adverse maternal and neonatal outcomes.

METHODS

Articles were searched using PubMed, Cochrane Library, and CINAHL from 1980 until 2005. Studies were included according to 3 criteria: if they reported duration of the second stage of labor, if they reported maternal and/or neonatal outcomes in relation to prolonged second stage, and if they reported original research.

RESULTS

Our systematic review found evidence of a strong association between prolonged second stage and operative delivery. Although significant associations with maternal outcomes such as postpartum hemorrhage, infection, and severe obstetric lacerations were reported, inherent limitations in methodology were evident in the studies. Recurrent limitations included oversimplified categorization of second stage, inconsistency in study population characteristics, and lack of control of confounding factors. No associations between prolonged second stage and adverse neonatal outcomes were reported.

CONCLUSIONS

The primary findings of our review indicated that most of the studies are flawed and do not answer the important questions for maternity caregivers to safely manage prolonged second stage. Meanwhile, approaches for promoting a normal second stage of labor are available to caregivers, such as maternal positioning and pain relief measures and also promoting effective pushing technique.