Intrapartum cesarean delivery in nulliparas: risk factors compared by two analytical approaches

Comparison of First Childbirth Characteristics between Elite Judo Athletes and Non-Athletes: The Preliminary Retrospective Case-Control Study

It has been speculated that elite athletes are more likely to have obstetric interventions during labor and delivery. So far, the impact of many years of competitive sports participation on childbirth characteristics has not been well-established. This preliminary retrospective case-control study aimed to determine whether the first labors of elite judo competitors required obstetric interventions more frequently and were longer than those of non-athletes. The study comprised 32 parous women: 16 elite judo athletes and 16 non-athletes. Women were included if they had access to the following obstetric data (from their first childbirth hospital discharge reports and/or first child's health record books): induction and augmentation of labor, mode of delivery, the duration of labor and its second stage, episiotomy, perineal tear, and the neonate's Apgar score. Electronic surveys were completed concerning childbirth characteristics, level of "eliteness" (judo athletes), and recreational physical activity (non-athletes). The statistical analysis showed no significant between-group differences in any of the first childbirth outcomes under analysis. The preliminary results indicate elite judo practice before first pregnancy had no negative impact on the rates of labor induction and augmentation, delivery mode, duration of labor, the rates of episiotomy and perineal tear, and the neonate's Apgar score. Due to the small sample size, the conclusions should be considered with caution.

Three machine learning algorithms and their utility in exploring risk factors associated with primary cesarean section in low-risk women: A methods paper

Machine learning, a branch of artificial intelligence, is increasingly used in health research, including nursing and maternal outcomes research. Machine learning algorithms are complex and involve statistics and terminology that are not common in health research. The purpose of this methods paper is to describe three machine learning algorithms in detail and provide an example of their use in maternal outcomes research. The three algorithms, classification and regression trees, least absolute shrinkage and selection operator, and random forest, may be used to understand risk groups, select variables for a model, and rank variables' contribution to an outcome, respectively. While machine learning has plenty to contribute to health research, it also has some drawbacks, and these are discussed as well. To provide an example of the different algorithms' function, they were used on a completed cross-sectional study examining the association of oxytocin total dose exposure with primary cesarean section. The results of the algorithms are compared to what was done or found using more traditional methods.

Dose dependent reduction in median effective concentration (EC50) of ropivacaine with adjuvant dexmedetomidine in labor epidural analgesia: An up-down sequential allocation study

STUDY OBJECTIVE

Adjuvant dexmedetomidine can be used to reduce the required concentration of ropivacaine for labor epidural analgesia. However, the potency of dexmedetomidine has not been fully studied. The purpose of this study was to determine the median effective concentration (EC₅₀) of ropivacaine with adjuvant dexmedetomidine.

DESIGN

Prospective, double-blind, up-down sequential allocation study.

SETTING

Academic medical center specializing in the care of women and children.

PATIENTS

One hundred and fifty healthy, term parturients requesting labor epidural analgesia were randomly assigned to 1 of 5 different concentrations of dexmedetomidine: 0 μg/ml, 0.3 μg/ml, 0.4 μg/ml, 0.5 μg/ml, or 0.6 μg/ml.

INTERVENTIONS

The study solution for the first patient in each group included the randomly assigned concentration of dexmedetomidine in 0.1% ropivacaine. Subsequent patients in each randomization group received the assigned concentration of dexmedetomidine in a new concentration of ropivacaine as determined by the up-down allocation methodology. Effective analgesia was defined as pain on the visual analogue scale of<3 at30 min after administration of local anesthetic. The up-down sequential allocation method and probit regression were used to calculate the EC₅₀ of epidural ropivacaine.

MEASUREMENTS

The primary outcome was pain 30 min after administration of local anesthetic via epidural catheter. Exploratory outcomes included side effects, neonatal outcomes, and obstetric outcomes.

MAIN RESULTS

The EC₅₀ values for ropivacaine in dexmedetomidine 0.4 μg/ml, 0.5 μg/ml, and 0.6 μg/ml (0.044% [95% CI 0.036% to 0.045%], 0.035% [95% CI 0.031% to 0.041%], and 0.039% [95% CI 0.034% to 0.045%], respectively) were lower compared to ropivacaine in dexmedetomidine 0 μg/ml and 0.3 μg/ml (0.086% [95% CI 0.081% to 0.092%], and, 0.069% [95% CI 0.056% to 0.076%], respectively). Differences between EC₅₀ values for ropivacaine in dexmedetomidine 0.4 μg/ml, 0.5 μg/ml, and 0.6 μg/ml were not statistically significant. Results of our exploratory analyses did not reveal differences in side effects, neonatal outcomes, or obstetric outcomes.

CONCLUSIONS

In this study, the lowest concentration of dexmedetomidine in ropivacaine with the greatest clinical effect was 0.4 μg/ml, which is important because there may be no additional analgesic benefit of dexmedetomidine greater than 0.4 μg/ml.

Predicting vaginal birth after previous cesarean: Using machine-learning models and a population-based cohort in Sweden

Introduction

Predicting a woman’s probability of vaginal birth after cesarean could facilitate the antenatal decision‐making process. Having a previous vaginal birth strongly predicts vaginal birth after cesarean. Delivery outcome in women with only a cesarean delivery is more unpredictable. Therefore, to better predict vaginal birth in women with only one prior cesarean delivery and no vaginal deliveries would greatly benefit clinical practice and fill a key evidence gap in research. Our aim was to predict vaginal birth in women with one prior cesarean and no vaginal deliveries using machine‐learning methods, and compare with a US prediction model and its further developed model for a Swedish setting.

Material and methods

A population‐based cohort study with a cohort of 3116 women with only one prior birth, a cesarean, and a subsequent trial of labor during 2008‐2014 in the Stockholm‐Gotland region, Sweden. Three machine‐learning methods (conditional inference tree, conditional random forest and lasso binary regression) were used to predict vaginal birth after cesarean among women with one previous birth. Performance of the new models was compared with two existing models developed by Grobman et al (USA) and Fagerberg et al (Sweden). Our main outcome measures were area under the receiver‐operating curve (AUROC), overall accuracy, sensitivity and specificity of prediction of vaginal birth after previous cesarean delivery.

Results

The AUROC ranged from 0.61 to 0.69 for all models, sensitivity was above 91% and specificity below 22%. The majority of women with an unplanned repeat cesarean had a predicted probability of vaginal birth after cesarean >60%.

Conclusions

Both classical regression models and machine‐learning models had a high sensitivity in predicting vaginal birth after cesarean in women without a previous vaginal delivery. The majority of women with an unplanned repeat cesarean delivery were predicted to succeed with a vaginal birth (ie specificity was low). Additional covariates combined with machine‐learning techniques did not outperform classical regression models in this study.

[Caesarean risk factors during labor for a class III obese nulliparous]

OBJECTIVES

Obesity is a well-known caesarean and obstetrical risk factor. However, the number of obese nulliparous women is increasing worldwide, creating an urgent need for research into the impact of obesity on the mode of delivery. Our objective was to identify caesarean risk factors in obese nulliparous women with a BMI (body mass index) greater than 40kg/m².

METHODS

A literature review was conducted on PubMed; including articles published between 2009 and 2019 in French and English, on caesarean risk during labor among class III obese nulliparous women.

RESULTS

One prospective study, and 6 retrospective analyses were included. Their results suggest that the rate of caesarean delivery increases with the BMI. Maternal age, particularly after 35 years, as well as induced labor and the use of oxytocin during labor, were positively associated with cesarean delivery. Moreover, maternal BMI was linked to an increased risk of non-elective caesarean section due to non-reassuring fetal heart tracing.

CONCLUSION

Extreme BMI, age, induced labor and oxytocin use are associated with caesarean delivery in nulliparous women with BMI≥40kg/m². Further research are needed to estimate the best candidates for elective cesarean delivery.

Chorioamnionitis at latent phase more than doubles the risk for cesarean delivery compared to chorioamnionitis at active phase

PURPOSE

Chorioamnionitis, or intraamniotic infection, is a common condition, carrying an increased risk of intrapartum cesarean delivery (CD). The morbidity related to chorioamnionitis is more common in those undergoing CD, as compared to those with successful vaginal delivery. We aimed to examine the risk factors associated with CD among women with chorioamnionitis.

METHODS

A retrospective cohort study from a tertiary medical center. We included women at term carrying a singleton gestation with suspected chorioamnionitis undergoing a trial of labor between 2011 and 2019. The primary outcome was the mode of delivery.

RESULTS

Data from 1436 women with chorioamnionitis were analyzed; 1288 (89.7%) were nulliparous. Overall, 1064 (74.1%) delivered vaginally, and 372 (25.9%) by CD. The rate of CD was significantly higher in nulliparous as compared to parous parturients (26.9% vs. 16.9%, P = 0.008), and in those with fever onset at latent phase as compared to those in whom fever appeared at active labor (≥ 6 cm) (47.0% vs. 18.1%, P < 0.001). In a multivariate analysis, CD was positively associated with: onset of fever at latent phase (aOR [95% CI] 4.75 (3.54, 6.32), P < 0.001), nulliparity (aOR [95% CI] 3.25 (1.98, 5.34), P < 0.001), maternal age (aOR [95% CI] 1.52 (1.10, 2.09), P = 0.01) and birth weight (aOR [95% CI] 1.23 (1.04, 1.44), P = 0.01).

CONCLUSION

Women with chorioamnionitis had a high rate of CD. Nulliparity and onset of fever prior to active labor were the strongest independent predictors of CD. It remains to be determined whether those deemed at high risk for failed trial of labor, should undergo CD earlier in the course of labor to improve chorioamnionitis-related outcomes.

The Role of Oxytocin in Primary Cesarean Birth Among Low-Risk Women

INTRODUCTION

To examine whether there is a threshold of oxytocin exposure at which the risk for primary cesarean increases among women who are nulliparous with a term, singleton, vertex fetus (NTSV) and how oxytocin interacts with other risk factors to contribute to this outcome.

METHODS

This was a secondary analysis of the Consortium on Safe Labor data set that used a retrospective cohort study design. Women who met the criteria for NTSV who were not admitted for a prelabor cesarean and for whom oxytocin data were available, were included in the sample. Robust logistic regression was used to examine the association of oxytocin exposure with primary cesarean birth, while controlling for demographic and clinical risk factors and clustering by provider.

RESULTS

The sample comprised 17,331 women who were exposed to oxytocin during labor. The women were predominantly white non-Hispanic (59.2%) with an average (SD) gestational age of 39.4 (1.1) weeks and an 18.5% primary cesarean rate. Exposure to greater than 11,400-milliunits (mU) of oxytocin resulted in 1.6 times increased odds of primary cesarean birth compared with less than 11,400 mU (95% CI 1.01-2.6).

DISCUSSION

Exposure to greater than 11,400 mU of oxytocin in labor was associated with an increased odds of primary cesarean birth in NTSV women.

Factors affecting failed trial of labor and countermeasures: A retrospective analysis

BACKGROUND

Vaginal delivery is the ideal mode of delivery for the termination of a pregnancy. However, the cesarean section rate in China is much higher than the published by the World Health Organization in the Lancet in 2010.

AIM

To retrospectively analyze the factors related to failed trial of labor and the clinical indications for cesarean section conversion, explore how to promote the trial of labor success rate, and determine the feasibility of reducing the rate of conversion to cesarean section.

METHODS

A retrospective analysis was performed on 9240 maternal women who met vaginal delivery conditions and required a trial of labor from January 2016 to December 2018 at our hospital. Among them, 8164 pregnant women who had a successful trial of labor were used as a control group, and 1076 pregnant women who had a failed trial of labor and converted to an emergency cesarean section were used as an observation group. The patients’ clinical data during hospitalization were collected for comparative analysis, the related factors of the failed trial of labor were discussed, and reasonable prevention and resolution strategies were proposed to increase the success rate of trial of labor.

RESULTS

The analysis revealed that advanced age (≥ 35 years old), macrosomia (≥ 4000 g), delayed pregnancy (≥ 41 wk), use of uterine contraction drugs, primipara, and fever during labor were associated with conversion to an emergency cesarean section in the failed trial of labor. Multivariate regression analysis showed that age, gestational age, primipara, use of uterine contraction drugs, fever during birth, and newborn weight led to a higher probability of conversion to an emergency cesarean section in the failed trial of labor. The analysis indicated that the following clinical indications were associated with the conversion to cesarean section in the failed trial of labor: Fetal distress (44.3%), social factors (12.8%), malpresentation (face presentation, persistent occipitoposterior position, and persistent occipitotransverse position) (9.4%), and cephalopelvic disproportion (8.9%).

CONCLUSION

The conversion to emergency cesarean section in failed trial of labor is affected by many factors. Medical staff should take appropriate preventive measures for the main factors, increase the trial of labor success rate, improve the quality of delivery, ensure the safety of mother and child during the perinatal period, and improve the relationship between doctors and patients.

Maternal and system characteristics, oxytocin administration practices, and cesarean birth rate

BACKGROUND

The cesarean birth rate in the United States is 32%, and there is discussion about the cause of high surgical birth rates. Our purpose was to determine whether mode of birth is influenced by maternal, nurse, and system factors.

METHODS

Secondary analysis of a data set of 163 women having postdates labor induction with oxytocin. Kaplan-Meier survival curves were calculated to compare the time for patients to reach an infusion rate of 6 mU/min, consistent with endogenous oxytocin levels in active labor. We used the log-rank test to evaluate survival curve differences. Multiple logistic regression and Cox proportional hazards models were conducted and included covariates that had statistically significant bivariate relationships with the time variable, or were clinically meaningful.

RESULTS

The mean time to reach 6 mU/min was longer for women who birthed by cesarean (172.5 minutes) than for women who had vaginal birth (125.0 minutes, P = .024). The mean time to reach 6 mU/min was also longer for women admitted on night shift (147.0 minutes) than day shift (110.2 minutes, P = .018). No maternal characteristics were significantly related to the time to reach a rate of 6 mU/min.

CONCLUSIONS

Even during the initial hours of labor induction, it is important that the oxytocin infusion is titrated appropriately to aid women in achieving timely vaginal birth. Intrapartum nurses should receive education about the pharmacokinetics of intravenous oxytocin to understand proper administration of this high-alert medication.

Using the Robson 10-Group Classification System to Compare Cesarean Birth Utilization Between US Centers With and Without Midwives

INTRODUCTION

The Robson 10-group classification system stratifies cesarean birth rates using maternal characteristics. Our aim was to compare cesarean birth utilization in US centers with and without midwifery care using the Robson classification.

METHODS

We used National Institute of Child and Human Development Consortium on Safe Labor data from 2002 to 2008. Births to women in centers with interprofessional care that included midwives (n = 48,857) were compared with births in non-interprofessional centers (n = 47,935). To compare cesarean utilization, births were classified into the Robson categories. Cesarean birth rates within each category and the contribution to the overall rate were calculated. Maternal demographics, labor and birth outcomes, and neonatal outcomes were described. Logistic regression was used to adjust for maternal comorbidities.

RESULTS

Women were less likely to have a cesarean birth (26.1% vs 33.5%, P < .001) in centers with interprofessional care. Nulliparous women with singleton, cephalic, term fetuses (category 2) were less likely to have labor induced (11.1% vs 23.4%, P < .001), and women with a prior uterine scar (category 5) had lower cesarean birth rates (73.8% vs 85.1%, P < .001) in centers with midwives. In centers without midwives, nulliparous women with singleton, cephalic, term fetuses with induction of labor (category 2a) were less likely to have a cesarean birth compared with those in interprofessional care centers in unadjusted comparison (30.3% vs 35.8%, P < .001), but this was reversed after adjustment for maternal comorbidities (adjusted odds ratio, 1.21; 95% CI, 1.12-1.32; P < .001). Cesarean birth rates among women at risk for complications (eg, breech) were similar between groups.

DISCUSSION

Interprofessional care teams were associated with lower rates of labor induction and overall cesarean utilization as well as higher rates of vaginal birth after cesarean. There was consistency in cesarean rates among women with higher risk for complications.

Influence of midwifery presence in United States centers on labor care and outcomes of low-risk parous women: A Consortium on Safe Labor study

BACKGROUND

Sixty percent of United States births are to multiparous women. Hospital-level policies and culture may influence intrapartum care and birth outcomes for this large population, yet have been poorly explored using a large, diverse sample. We sought to use national United States data to analyze the association between midwifery presence in maternity care teams and the birth processes and outcomes of low-risk parous women.

METHODS

We conducted a retrospective cohort study using Consortium on Safe Labor data from low-risk parous women in either interprofessional care (n = 12 125) or noninterprofessional care centers (n = 8996). Unadjusted, adjusted (age, race, health insurance type), propensity-adjusted, and propensity-matched logistic regression models were used to assess processes and outcomes.

RESULTS

There was concordance in outcome differences across regression models. With propensity score matching, women at interprofessional centers, compared with women at noninterprofessional centers, were 85% less likely to have labor induced (risk ratio [RR] 0.15; 95% CI 0.14-0.17). The risk for primary cesarean birth among low-risk parous women was 36% lower at interprofessional centers (RR 0.64; 95% CI 00.52-0.79), whereas the likelihood of vaginal birth after cesarean for this population was 31% higher (RR 1.31; 95% CI 1.10-1.56). There were no significant differences in neonatal outcomes.

CONCLUSIONS

Parous women have significantly higher rates of vaginal birth, including vaginal birth after cesarean, and lower likelihood of labor induction when cared for in centers with midwives. Our findings are consistent with smaller analyses of midwifery practice and support integrated, team-based models of perinatal care to improve maternal outcomes.

Building a predictive model for successful vaginal delivery in nulliparas with term cephalic singleton pregnancies using decision tree analysis

AIM

To establish a model predicting successful vaginal delivery (VD) in nulliparas with term cephalic singleton pregnancies.

METHODS

We retrospectively identified 6799 term nulliparas with cephalic singletons (6416 VD and 383 cesarean section [CS] due to dystocia) who entered labor (cervical dilation ≥2 cm) between September 2014 and August 2015. Using VD as the dependent variable and age, maternal body height, educational attainment, gravidity, gestational age, pre-pregnancy body mass index (BMI), BMI upon admission for delivery, gestational weight gain, gestational hypertension and gestational diabetes as the independent variables, predictors of VD success were identified using a multivariate binary logistic regression and then ranked with decision-tree analysis.

RESULTS

While multiple factors are associated with improved VD success, we found body height, gestational age, and intrapartum BMI to be the best predictors of successful VD. Our predictive model has a classification accuracy, sensitivity and specificity of 76.6%, 96.7% and 16.4%, respectively, and it was subsequently confirmed by both internal and external validation.

CONCLUSION

Our predictive model indicates body height, gestational age and intrapartum BMI as the major predictors of successful VD in low-risk patients.

Impact of obesity and other risk factors on labor dystocia in term primiparous women: a case control study

BACKGROUND

Purpose of this study was to investigate differences between primiparous term pregnancies, one leading to vaginal delivery (VD) and the other to acute cesarean section (CS) due to labor dystocia in the first stage of labor. We particularly wanted to assess the influence of body mass index (BMI) on CS risk.

METHODS

A retrospective case-control study in a tertiary delivery unit with 5200 deliveries annually. Cases were 296 term primiparous women whose intended vaginal labor ended in acute CS because of dystocia. Controls were primiparas with successful vaginal delivery VD (n = 302). The data were retrieved from medical records. Multiple logistic regression analyses were used to assess the associations between BMI and covariates on labor dystocia.

RESULTS

In the cases ending with acute CS, women were older (OR 1.06 [1.03-1.10]), shorter (OR 0.94 [0.91-0.96]) and more often had a chronic disease (OR 1.60 [1.1-2.29]). In this group fetal malposition (OR 42.0 [19.2-91.9]) and chorioamnionitis (OR 10.9 [5.01-23.6]) were more common, labor was less often in an active phase (OR 3.37 [2.38-4.76]) and the cervix was not as well ripened (1.5 vs. 2.5 cm, OR 0.57 [0.48-0.67] on arrival at the birth unit. BMI was higher in the dystocia group (24.1 vs. 22.6 kg/m2, p < 0.001), and rising maternal pre-pregnancy BMI had a strong association with dystocia risk. If BMI increased by 1 kg/m2, the risk of CS was 10% elevated. Among obese primiparas, premature rupture of membranes, chorioamnionitis and induction of labor were more common. Their labors were less often in an active phase at hospital admission. Severely obese primiparas (BMI ≥ 35 kg/m2) had 4 hours longer labor than normal-weight parturients.

CONCLUSIONS

Labor dystocia is a multifactorial phenomenon in which the possibility to ameliorate the condition via medical treatment is limited. Hospital admission at an advanced stage of labor is recommended. Pre-pregnancy weight control in the population at reproductive age is essential, as a high BMI is strongly associated with labor dystocia.

Predictive modeling of emergency cesarean delivery

OBJECTIVE

To increase discriminatory accuracy (DA) for emergency cesarean sections (ECSs).

STUDY DESIGN

We prospectively collected data on and studied all 6,157 births occurring in 2014 at four public hospitals located in three different autonomous communities of Spain. To identify risk factors (RFs) for ECS, we used likelihood ratios and logistic regression, fitted a classification tree (CTREE), and analyzed a random forest model (RFM). We used the areas under the receiver-operating-characteristic (ROC) curves (AUCs) to assess their DA.

RESULTS

The magnitude of the LR+ for all putative individual RFs and ORs in the logistic regression models was low to moderate. Except for parity, all putative RFs were positively associated with ECS, including hospital fixed-effects and night-shift delivery. The DA of all logistic models ranged from 0.74 to 0.81. The most relevant RFs (pH, induction, and previous C-section) in the CTREEs showed the highest ORs in the logistic models. The DA of the RFM and its most relevant interaction terms was even higher (AUC = 0.94; 95% CI: 0.93-0.95).

CONCLUSION

Putative fetal, maternal, and contextual RFs alone fail to achieve reasonable DA for ECS. It is the combination of these RFs and the interactions between them at each hospital that make it possible to improve the DA for the type of delivery and tailor interventions through prediction to improve the appropriateness of ECS indications.

Exercise and pregnancy in recreational and elite athletes: 2016 evidence summary from the IOC expert group meeting, Lausanne. Part 2-the effect of exercise on the fetus, labour and birth

This is Part 2 of 5 in the series of evidence statements from the IOC expert committee on exercise and pregnancy in recreational and elite athletes. Part 1 focused on the effects of training during pregnancy and on the management of common pregnancy-related symptoms experienced by athletes. In Part 2, we focus on maternal and fetal perinatal outcomes.