New labor curves of dilation and station to improve the accuracy of predicting labor progress.

BACKGROUND: The diagnosis of failure to progress, the most common indication for intrapartum cesarean delivery, is based on the assessment of cervical dilation and station over time. Labor curves serve as references for expected changes in dilation and fetal descent. The labor curves of Friedman, Zhang et al, and others are based on time alone and derived from mothers with spontaneous labor onset. However, labor induction is now common, and clinicians also consider other factors when assessing labor progress. Labor curves that consider the use of labor induction and other factors that influence labor progress have the potential to be more accurate and closer to clinical decision-making. OBJECTIVE: This study aimed to compare the prediction errors of labor curves based on a single factor (time) or multiple clinically relevant factors using two modeling methods: mixed-effects regression, a standard statistical method, and Gaussian processes, a machine learning method. STUDY DESIGN: This was a longitudinal cohort study of changes in dilation and station based on data from 8022 births in nulliparous women with a live, singleton, vertex-presenting fetus ≥35 weeks of gestation with a vaginal delivery. New labor curves of dilation and station were generated with 10-fold cross-validation. External validation was performed using a geographically independent group. Model variables included time from the first examination in the 20 hours before delivery; dilation, effacement, and station recorded at the previous examination; cumulative contraction counts; and use of epidural anesthesia and labor induction. To assess model accuracy, differences between each model's predicted value and its corresponding observed value were calculated. These prediction errors were summarized using mean absolute error and root mean squared error statistics. RESULTS: Dilation curves based on multiple parameters were more accurate than those derived from time alone. The mean absolute error of the multifactor methods was better (lower) than those of the single-factor methods (0.826 cm [95% confidence interval, 0.820-0.832] for the multifactor machine learning and 0.893 cm [95% confidence interval, 0.885-0.901] for the multifactor mixed-effects method and 2.122 cm [95% confidence interval, 2.108-2.136] for the single-factor methods; P<.0001 for both comparisons). The root mean squared errors of the multifactor methods were also better (lower) than those of the single-factor methods (1.126 cm [95% confidence interval, 1.118-1.133] for the machine learning [P<.0001] and 1.172 cm [95% confidence interval, 1.164-1.181] for the mixed-effects methods and 2.504 cm [95% confidence interval, 2.487-2.521] for the single-factor [P<.0001 for both comparisons]). The multifactor machine learning dilation models showed small but statistically significant improvements in accuracy compared to the mixed-effects regression models (P<.0001). The multifactor machine learning method produced a curve of descent with a mean absolute error of 0.512 cm (95% confidence interval, 0.509-0.515) and a root mean squared error of 0.660 cm (95% confidence interval, 0.655-0.666). External validation using independent data produced similar findings. CONCLUSION: Cervical dilation models based on multiple clinically relevant parameters showed improved (lower) prediction errors compared to models based on time alone. The mean prediction errors were reduced by more than 50%. A more accurate assessment of departure from expected dilation and station may help clinicians optimize intrapartum management.

The evolution of the labor curve and its implications for clinical practice: the relationship between cervical dilation, station, and time during labor.

The assessment of labor progress is germane to every woman in labor. Two labor disorders-arrest of dilation and arrest of descent-are the primary indications for surgery in close to 50% of all intrapartum cesarean deliveries and are often contributing indications for cesarean deliveries for fetal heart rate abnormalities. Beginning in 1954, the assessment of labor progress was transformed by Friedman. He published a series of seminal works describing the relationship between cervical dilation, station of the presenting part, and time. He proposed nomenclature for the classification of labor disorders. Generations of obstetricians used this terminology and normal labor curves to determine expected rates of dilation and fetal descent and to decide when intervention was required. The analysis of labor progress presents many mathematical challenges. Clinical measurements of dilation and station are imprecise and prone to variation, especially for inexperienced observers. Many interrelated factors influence how the cervix dilates and how the fetus descends. There is substantial variability in when data collection begins and in the frequency of examinations. Statistical methods to account for these issues have advanced considerably in recent decades. In parallel, there is growing recognition among clinicians of the limitations of using time alone to assess progress in cervical dilation in labor. There is wide variation in the patterns of dilation over time and most labors do not follow an average dilation curve. Reliable assessment of labor progression is important because uncertainty leads to both over-use and under-use of cesarean delivery and neither of these extremes are desirable. This review traces the evolution of labor curves, describes how limitations are being addressed to reduce uncertainty and to improve the assessment of labor progression using modern statistical techniques and multi-dimensional data, and discusses the implications for obstetrical practice.

Oxycodone does not affect placental circulatory physiology during the early first stage of labor-A randomized trial.

INTRODUCTION: Opioids are used for pain relief during the first stage of labor. Oxycodone can cause maternal hypotension that may modify utero- and fetoplacental circulatory physiology. We hypothesized that maternal intravenous (i.v.) oxycodone has no detrimental effect on utero- and fetoplacental hemodynamics during the early first stage of labor. MATERIAL AND METHODS: Twenty-two parturients requiring pain relief during the first stage of labor were randomized in a double-blinded and placebo-controlled study. By Doppler ultrasonography, both uterine artery (Ut) and umbilical vein (UV) volume blood flows (Q), Ut pulsatility index (PI), and Ut vascular resistance (RUt) were calculated. Blood flow velocity waveforms were obtained between uterine contractions. After baseline measurements, women received oxycodone 0.05 mg/kg or a placebo intravenous. Doppler ultrasonography was repeated up to 120 min after the first drug administration. The second dose of oxycodone 0.05 mg/kg was allowed at 60 min to all parturients with contraction pain ≥5/10. Maternal plasma samples were collected at each study phase and after delivery with umbilical cord plasma samples, to measure oxycodone concentrations. CLINICALTRIALS: gov identifier (NCT no. NCT02573831). RESULTS: At baseline, mean QUt and QUV did not differ significantly between the placebo-first (478 mL/min and 57 mL/min/kg) and the oxycodone-first (561 mL/min and 71 mL/min/kg) groups. In addition, RUt and Ut PI were comparable between the groups. Following oxycodone at 60 min, mean QUt and QUV (714 mL/min and 52 mL/min/kg) were similar to the placebo-first (520 mL/min and 55 mL/min/kg) group. Furthermore, all the measured parameters were comparable to the baseline values. At 60 min after the first study drug administration, all the parturients in the placebo-first group needed intravenous oxycodone 0.05 mg/kg. At 120 min, we found no statistically significant change in any of the measured parameters. No significant correlation was found between maternal oxycodone concentration and QUt or QUV. Furthermore, newborn oxycodone concentration did not correlate with QUV. CONCLUSIONS: Oxycodone did not have any detrimental effect on either utero- or fetoplacental circulatory physiology during the early first stage of labor. Maternal plasma oxycodone did not correlate with utero- and fetoplacental hemodynamics. No correlation was found between newborn oxycodone concentration and fetoplacental hemodynamics.

Induction of labour in mid-trimester pregnancy using double-balloon catheter placement within 12 h versus within 12-24 h.

BACKGROUND: This study aims to evaluate the efficacy and safety of the induction of labour in mid-trimester pregnancy using a double-balloon catheter (DBC) within 12 h versus within 12-24 h. METHODS: In this retrospective study, a total of 58 pregnant women at 14 + 0 weeks to 27 + 6 weeks of gestation were enrolled as research subjects, and they underwent the intended termination of pregnancy at our birth centre from January 1, 2017, to June 31, 2019. Based on the duration of DBC, the patients were divided into two groups, namely, the DBC group within 12 h and the DBC group within 12-24 h. RESULTS: All 58 cases were successful vaginal deliveries, and no one chose to undergo caesarean section. The success rate of induction (successful abortion of the foetus and placenta without the implementation of dilation and evacuation) was higher in the DBC group within 12-24 h (96.3%, 29/31) than in the DBC group within 12 h (71.0%, 18/27) (p < 0.05). Additionally, the time from DBC removal to delivery in the DBC group within 12-24 h was significantly shorter than that in the DBC group within 12 h (3.0 h versus 17.8 h) (p < 0.05), and the degree of cervical dilation after DBC removal in the DBC group within 12-24 h was larger than that in the DBC group within 12 h (p < 0.05). CONCLUSION: In the clinic, the placement time of DBC generally lasts for approximately 12 h. However, considering that the cervical condition is immature in the mid-trimester, properly extending the placement time of DBC to 24 h will benefit cervical ripening and reduce the chance of dilation and evacuation.

Labor Dystocia in Nulliparous Women.

Dystocia (abnormally slow or protracted labor) accounts for 25% to 55% of primary cesarean deliveries. The latent phase of labor begins with onset of regular, painful contractions and continues until 6 cm of cervical dilation. Current recommendations are to avoid admission to labor and delivery during the latent phase, assuming maternal/fetal status is reassuring. The active phase begins at 6 cm. An arrested active phase is defined as more than four hours without cervical change despite rupture of membranes and adequate contractions and more than six hours of no cervical change without adequate contractions. Managing a protracted active phase includes oxytocin augmentation with or without amniotomy. The second stage of labor begins at complete cervical dilation and continues to delivery. This stage is considered protracted if it lasts three hours or more in nulliparous patients without an epidural or four hours or more in nulliparous patients with an epidural. Primary interventions for a protracted second stage include use of oxytocin and manual rotation if the fetus is in the occiput posterior position. When contractions or pushing is inadequate, vacuum or forceps delivery may be needed. Effective measures for preventing dystocia and subsequent cesarean delivery include avoiding admission during latent labor, providing cervical ripening agents for induction in patients with an unfavorable cervix, encouraging the use of continuous labor support (e.g., a doula), walking or upright positioning in the first stage, and not diagnosing failed induction during the latent phase until oxytocin has been given for 12 to 18 hours after membrane rupture. Elective induction at 39 weeks' gestation in low-risk nulliparous patients may reduce the risk of cesarean delivery.

A Novel Partogram for Stages 1 and 2 of Labor Based on Fetal Head Station Measured by Ultrasound: A Prospective Multicenter Cohort Study.

OBJECTIVE: This study was aimed to describe continuous labor curves, including second stage, based on fetal head station. STUDY DESIGN: We performed a prospective multicenter cohort study. The inclusion criteria were women with singleton uncomplicated cephalic term pregnancies in labor, who delivered vaginally. We used a device that combines ultrasound imaging with position-tracking technology to monitor the head station noninvasively throughout labor. We collected data on demographics, labor parameters, and delivery and neonatal outcomes. RESULTS: A total of 613 women delivered vaginally, 327 (53.3%) were nulliparous, while 286 (46.7%) were multiparous. Time to delivery (TTD) diminished progressively with descent of the fetal head. When the head is engaged, the labor curve of multiparous women demonstrated a more prominent downward shift in curve as compared with nulliparous women. When comparing multipara and nullipara at engagement level, the median TTD was 1 and 1.62 hours, respectively. In 95% of women with unengaged head during the second stage, TTD of nulliparous and multiparous women were less than 3.8 and 3 hours, respectively. CONCLUSION: While current labor curves end at full dilatation, the described curves were developed throughout stages 1 and 2 of labor. The TTD, according to the station curves, shows an acceleration of labor, once passed the engagement level, especially in multiparous women.

Progression of the first stage of labour, in low risk nulliparas in a South Asian population: a prospective observational study.

We compared the labour pattern in the active phase of labour, defined at 4 cm versus 6 cm cervical dilatation, in a South Asian population. This was a prospective observational study where 500 low risk nulliparous women were recruited. Our aim was to study, the average labour pattern curve of all parturients. Mean duration of the active phase from 4 to 10 cm was 5.12 ± 2.10 hours and from 6 to 10 cm was 2.79 ± 1.72 hours. The 95th percentile values suggests that it takes 5-6 hours to progress from 4 to 6 cm and again 5-6 hours from 6 to 10 cm. The minimum labour progression rate can be as low as 0.5 cm/hour with vaginal delivery (VD) still being achieved. The slope of labour curve steepens after 6 cm, suggesting 6 cm as the onset of the active phase. Allowing labour to continue for a longer period before 6 cm of cervical dilation may reduce the rate of unnecessary intrapartum intervention and caesarean section (CS) for labour dystocia.Impact StatementWhat is already known on this subject? Friedman's definitions of normal labour and abnormal labour are widely accepted in current obstetric practises. Friedman's normal dilatation rate of 1 cm/h that is universally accepted is becoming questionable in our current obstetric population because of escalating rates of unnecessary labour interventions like oxytocin augmentation and CS.What the results of this study add? The rule of 1 cm/hour of labour progression cannot be applied to every woman and inappropriate interventions should be withheld until labour progression does falls below 0.5 cm/hour.What the implications are of these findings for clinical practice and/or further research? Six centimetres rather than 4 cm of cervical dilatation is a more appropriate landmark for the start of the active phase. Allowing labour to continue for a longer period before 6 cm of cervical dilation may reduce the rate of unnecessary intrapartum interventions and CS for labour dystocia.

The relationship between Cormic Index and uterine contractions' pattern in the active phase of the first stage of labour.

Uterine contractions are indicators of labour progress. The relationship between anthropometric indices and types of childbirth has been investigated. One of these indices is referred to as the Cormic Index, which provides an estimation of the sitting height and leg length. This cross-sectional study was performed to determine the relationship between the Cormic Index and the uterine contractions' pattern in the active phase of the first stage of labour. The standing and sitting heights of 150 pregnant women were measured to calculate the Cormic Index. Then, two Cardiotocographic traces were recorded during the 3 to 5 and 6 to 8 centimetres' dilations, by which the uterine contractions' pattern were determined. The mean Cormic Index was 51.84 ± 2.62. The results indicated that the Cormic Index had a positive linear correlation with MTIME (frequency of contractions) in the first monitoring episode and SDTIME (regularity of contractions) in the first and the second monitoring episode, which was significant (p < .05). However, there was no significant correlation between the Cormic Index and F:R ratio (shape of contractions) in both monitoring episodes. With the rise of the mother's Cormic Index, the frequency of contractions in the acceleration phase, and also their regularity in the acceleration phase and the phase of the maximum slope, were decreased during the active phase of labour.IMPACT STATEMENTWhat is already known on this subject? Uterine Contraction as an indicator of labour progress enforces cervical dilation. If uterine activity is analysed through electronic methods, one could assess labour outcome through some patterns of the contractions. Anthropometry provides a quick determination of the body proportions. The Cormic Index provides an estimation of the upper and lower body length. Several studies have investigated the relationship between the anthropometric indices and the types of childbirth. Despite the various approaches available, there is no objective means of precisely distinguishing the fact that whether labour can be successful in effecting vaginal delivery or not and diagnosis of dystocia still relies on the trial of labour.What do the results of this study add? The results of this study add to the growing body of research on the progression of labour that Cormic Index has a positive linear correlation with the frequency of contractions in acceleration phase, and with the regularity of contractions in the acceleration phase and the phase of maximum slope.What are the implications of these findings for clinical practice and/or further research? The results can help professionals to evaluate the progress of labour based on the type of uterine contractions in the latent phase or the early active phase of labour using the Cormic Index.

Factors that affect ultrasound-determined labor progress in women undergoing induction of labor.

BACKGROUND: The traditional approach to the assessment of labor progress is by digital vaginal examination; however, it is subjective and imprecise. Recent studies have investigated the role of transperineal ultrasonographic assessment of fetal head descent by measuring the angle of progression and head-perineum distance. OBJECTIVE: The objective of this study was to evaluate factors that affected labor progress, which were defined by the transperineal ultrasonographic parameters, in women who achieved vaginal delivery. STUDY DESIGN: This was a prospective longitudinal study performed in 315 women with singleton pregnancy who underwent labor induction at term between December 2016 and December 2017. Paired assessment of cervical dilation and fetal head station by vaginal examination and transperineal ultrasonographic assessment of fetal head descent (parasagittal angle of progression and head-perineum distance) were made serially after the commencement of labor induction until full cervical dilation. The researchers were blinded to the findings of the clinical team's vaginal examination and vice versa. The repeated measure data were analyzed by mixed effect models to identify the significant factors (age ≥35 years, obesity, parity, methods of labor induction, and epidural anesthesia) that affected the relationship between parasagittal angle of progression and head-perineum distance against fetal head station and cervical dilation. RESULTS: The total number of paired vaginal examination and transperineal ultrasonographic assessments among the 261 women (82.9%) with vaginal delivery was 945, with a median of 3 per woman. The median assessment-to-assessment interval was 4.6 hours (interquartile range, 4.3-5.2). Multiparity and mechanical methods of labor induction were associated with a faster rate of fetal head descent, which was determined by head-perineum distance against fetal head station, than nulliparity and the use of a slow-release vaginal pessary, respectively. An additional increase of 0.10 cm in head-perineum distance was observed, for an unit increase in fetal head station in nulliparous women (P=.03) and women who had a slow-release vaginal pessary (P=.02), compared with multiparous women and those who had mechanical methods for labor induction. The use of epidural anesthesia was associated with a slower rate of fetal head descent, which was determined by both parasagittal angle of progression and head-perineum distance, against fetal head station. An additional decrease of 3.66 degrees in parasagittal angle of progression (P=.04) and an additional increase in 0.33 cm in head-perineum distance (P≤.001) were observed for a unit increase in fetal head station in women with the use of epidural anesthesia, compared with those without. Obese women had higher head-perineum distance overall, compared with normal weight women; at different cross-sections of time periods, obesity appeared to be associated with a slower rate of change between head-perineum distance and cervical dilation. Advanced maternal age did not affect transperineal ultrasound-determined labor progress (P>.05). CONCLUSION: Parity, methods of labor induction, the use of epidural anesthesia, and obesity affect labor progress, which has been illustrated objectively by serial transperineal ultrasonographic assessment of fetal head descent.

First stage of labor progression in women with large-for-gestational age infants.

BACKGROUND: Women with suspected large-for-gestational age fetuses have higher rates of dysfunctional labor and labor arrest diagnoses and, consequently, higher rates of cesarean deliveries. The identification of the factors that significantly affect labor progression of women with large-for-gestational age infants may better inform expected duration of labor for certain subgroups of this population. OBJECTIVE: Because the standards for the first stage of labor when large-for-gestational age is present have not been defined clearly, the present study aims to evaluate labor progress of women with large-for-gestational age infants who complete the first stage of labor after 3-cm cervical dilation. STUDY DESIGN: We conducted a retrospective cohort study of patients who were admitted for labor from 2004-2014 with a term vertex singleton who achieved 10-cm cervical dilation. Labor curves were constructed with repeated measures regression and were compared between patients who delivered large-for-gestational age infants (actual birthweight, >90th percentile for gestational age) and those who delivered appropriate-for-gestational age infants (actual birthweight, 10-90th percentile for gestational age). Interval-censored regression estimated median duration of labor after 3-cm cervical dilation stratified by actual infant birthweight and further stratified by parity (nulliparity vs multiparity), labor onset (spontaneous [augmented and not augmented] and induced labor), pregestational diabetes mellitus or gestational diabetes mellitus status, and maternal body mass index (obese, ≥30 kg/m2 vs not obese, <30 kg/m2). Multivariate analysis adjusted for confounding factors that were identified by bivariate analysis. RESULTS: Among all 17,097 women who were included, 15,843 women (92.7%) had appropriate-for-gestational age infants; 1254 women (7.3%) had large-for-gestational age infants, of whom 387 (30.9%) were nulliparous; 464 women (37.0%) underwent induction of labor; 863 women (68.8%) were obese, and 158 women (12.6%) had diabetes mellitus or gestational diabetes mellitus. Women with large-for-gestational age infants had a slower progression from 3- to 10-cm cervical dilation compared with those with appropriate-for-gestational age infants (median, 8.57 hours [5th, 95th percentile, 2.95, 24.86] vs 6.46 hours [5th, 95th percentile, 2.23, 18.74]; P<.01). In the large-for-gestational age group, dilation from 6-10 cm progressed slower in nulliparous compared with multiparous women (3.28 hours [5th, 95th percentile, 0.71, 15.16] vs 2.03 hours [5th, 95th percentile, 0.44, 9.39]; P<.01) and in obese compared with not obese women (2.36 hours [5th, 95th percentile, 0.51, 10.91] vs 1.79 hours [5th, 95th percentile, 0.39, 8.31]; P<.01). Labor curves did not differ between large-for-gestational age and appropriate-for-gestational age groups when stratified by labor onset (nonaugmented spontaneous labor vs induced labor) or the presence of diabetes mellitus or gestational diabetes mellitus. CONCLUSION: After 3-cm cervical dilation, the time required to reach the second stage of labor is greater in women with large-for-gestational age infants compared with those with appropriate-for-gestational age infants; these differences are most pronounced in nulliparous and obese women with large-for-gestational age infants in the active phase of labor (6-10 cm). Among women with large-for-gestational age infants, labor onset and presence of diabetes mellitus or gestational diabetes mellitus have no apparent effect on the duration of the first stage of labor after 3-cm cervical dilation.

Prospective observational study of vaginal microbiota pre- and post-rescue cervical cerclage.

OBJECTIVE: To investigate the relation between vaginal microbiota composition and outcome of rescue cervical cerclage. DESIGN: Prospective observational study. SETTING: Queen Charlotte's and Chelsea Hospital, London. POPULATION: Twenty singleton pregnancies undergoing a rescue cervical cerclage. METHODS: Vaginal microbiota composition was analysed in women presenting with a dilated cervix and exposed fetal membranes before and 10 days following rescue cervical cerclage and was correlated with clinical outcomes. MAIN OUTCOME MEASURES: Composition of vaginal bacteria was characterised by culture-independent next generation sequencing. Successful cerclage was defined as that resulting in the birth of a neonate discharged from hospital without morbidity. Unsuccessful cerclage was defined as procedures culminating in miscarriage, intrauterine death, neonatal death or significant neonatal morbidity. RESULTS: Reduced Lactobacillus spp. relative abundance was observed in 40% of cases prior to rescue cerclage compared with 10% of gestation age-matched controls (8/20, 40% versus 3/30, 10%, P = 0.017). Gardnerella vaginalis was over-represented in women presenting with symptoms (3/7, 43% versus 0/13, 0%, P = 0.03, linear discriminant analysis, LDA (log 10) and cases culminating in miscarriage (3/6, 50% versus 0/14, 0%, P = 0.017). In the majority of cases (10/14, 71%) bacterial composition was unchanged following cerclage insertion and perioperative interventions. CONCLUSIONS: Reduced relative abundance of Lactobacillus spp. is associated with premature cervical dilation, whereas high levels of G. vaginalis are associated with unsuccessful rescue cerclage cases. The insertion of a rescue cerclage does not affect the underlying bacterial composition in the majority of cases. TWEETABLE ABSTRACT: Preterm cervical dilatation associates with reduced Lactobacillus spp. Presence of Gardnerella vaginalis predicts rescue cerclage failure.

Use of intrapartum ultrasound in term pregnant women with contractions before hospital admission.

INTRODUCTION: The aim of this study was to test the hypothesis that transperineal ultrasound can be used to decide whether to admit a pregnant woman due to labor. MATERIAL AND METHODS: In this analytical cross-sectional observational study, transperineal ultrasound was performed on pregnant women with intact membranes who came to the hospital due to contractions. A decision was made to admit women due to labor based on the ultrasound measurements. The ultrasound measurements were used to determine cervical dilation, the angle of progression, and fetal head position. The managing midwives were blinded to the results and made the final decision to admit the women based on digital vaginal examination. RESULTS: It was possible to decide whether a woman had to be admitted for delivery or discharged due to the latent phase of labor according to the ultrasound examination in 55 of the 57 cases (96.5%). In four of the 55 cases, the decision based on ultrasound differed from the midwife's decision (7.3%). There was strong agreement between the decision to admit the pregnant women based on ultrasound measurements and the digital vaginal examination (Cohen's kappa: 0.844). It was possible to measure cervical dilation with ultrasound in 52 of the 57 cases (91.2%). The intraclass correlation coefficient for the cervical dilation measurements was 0.736 (95% confidence interval 0.539-0.848). CONCLUSIONS: There was strong agreement between the ultrasound and digital vaginal examination results in the decision to admit singleton pregnant women at term due to labor. A large number of vaginal examinations could be avoided by using intrapartum ultrasound.

Advanced cervical dilatation as a predictor for low emergency cesarean delivery: a comparison between migrant and non-migrant Primiparae - secondary analysis in Berlin, Germany.

BACKGROUND: Cesarean rates are higher in women admitted to labor ward during early stages rather than at later stages of labor. In a study in Germany, crude cesarean rates among Turkish and Lebanese immigrant women were low compared to non-immigrant women. We evaluated whether these immigrant women were admitted during later stages of labor, and if so, whether this explains their lower cesarean rates. METHODS: We enrolled 1413 nulliparous women with vertex pregnancies, singleton birth, and 37+ week of gestation, excluding elective cesarean deliveries, in three Berlin obstetric hospitals. We applied binary logistic regression to adjust for social and obstetric factors; and standardized coefficients to rank predictors derived from the regression model. RESULTS: At the time of admission to labor ward, a smaller proportion of Turkish migrant women was in the active phase of labor (cervical dilation: 4+ cm), compared to women of Lebanese origin and non-immigrant women. Rates of cesarean deliveries were lower in women of Turkish and Lebanese origin (15.8 and 13.9%) than in non-immigrant women (23.9%). In the logistic regression analysis, more advanced cervical dilatation was inversely associated with the outcome cesarean delivery (OR: 0.76, 95%CI: 0.70-0.82). In addition, higher maternal age (OR: 1.06, 95%CI: 1.04-1.09), application of oxytocic agents (OR: 0.55, 95%CI: 0.42-0.72), and obesity (OR: 2.25, 95%CI: 1.51-3.34) were associated with the outcome. Ranking of predictors indicate that cervical dilatation is the most relevant predictor derived from the regression model. CONCLUSIONS: Advanced cervical dilatation at the time of admission to labor ward does not explain lower emergency cesarean delivery rates in Turkish and Lebanese migrant women, despite the fact that this is the strongest among the predictors for emergency cesarean delivery identified in this study.

Predicting asymptomatic cervical dilation in pregnant patients with short mid-trimester cervical length: A secondary analysis of a randomized controlled trial.

INTRODUCTION: Second trimester asymptomatic cervical dilation is a significant risk factor for early preterm birth. The objective of this study is to evaluate whether transvaginal ultrasound cervical length (CL) predicts asymptomatic cervical dilation on physical exam in women with short cervix (CL ≤25 mm) and no prior preterm birth. MATERIAL AND METHODS: Secondary analysis of a randomized trial on pessary in asymptomatic singletons without prior preterm birth diagnosed with CL ≤25 mm between 18+0/7 and 23+6/7  weeks. Participants had transvaginal ultrasound and physical cervical exam and were randomized to pessary or no pessary with all patients with cervical length ≤20 mm offered vaginal progesterone. The primary outcome was to determine whether CL was predictive of asymptomatic physical cervical dilation ≥1 cm using receiver operating characteristic curve. RESULTS: In all, 119 women were included. Based on receiver operating characteristic curve, CL ≤11 mm was best predictive of cervical dilation ≥1 cm, with 75% sensitivity, 80% specificity, and area under the curve 0.73 (0.55-0.91), P = 0.009. Cervical length ≤11 mm had increased incidence of cervical dilation ≥1 cm on physical exam (30% vs 3%, odds ratio 12.29 (3.05-49.37) P < 0.001) with a negative predictive value of 97%. Patients with ≥1 cm dilation had increased preterm birth <37 weeks (75% vs 39%, P = 0.03) compared to those not dilated. Women with a CL ≤11 mm had increased preterm birth <37 weeks (77% vs 31%, P < 0.001), preterm birth <34 weeks (63% vs 22%, P < 0.001), and lower birthweight (1552 ± 1047 vs 2560 ± 1072 g, P < 0.001) compared to women with CL >11 mm. CONCLUSIONS: Among singletons without prior preterm birth diagnosed with short cervix (≤25 mm), CL ≤11 mm may identify a subgroup of patients at high risk for asymptomatic cervical dilation and poor perinatal outcome. Physical exam should be considered and adjunctive preterm birth prevention measures should be studied in singletons with CL ≤11 mm.

Normal Cervical Effacement in Term Labor.

OBJECTIVE: To estimate the natural history of cervical effacement in labor. STUDY DESIGN: This is a retrospective cohort study of term, vertex, singletons who reached 10 cm of cervical dilation from 2010 to 2014. Interval-censored regression was used to estimate the median number of hours between changes in effacement (measured in centimeters of the residual cervix) and to estimate the median effacement at a given cervical dilation. Analysis was stratified by parity and labor type. RESULTS: In total, 7,319 patients were included. Multiparas had faster effacement from 1 cm to complete effacement than nulliparas, but nulliparas were significantly more effaced at each cervical dilation. Patients in spontaneous labor had faster effacement and were significantly more effaced at each centimeter of cervical dilation than those who were induced or augmented. Once active labor was established (>6 cm of cervical dilation), 95% of patients had an effacement of 1 cm or less. By 8 cm of cervical dilation, 50% of all patients were completely effaced. CONCLUSION: There is a wide range in the normal length of time for the progression of cervical effacement. However, once a patient is in active labor, 95% of patients have effaced to 1 cm or less.

Progression of the first stage of spontaneous labour: A prospective cohort study in two sub-Saharan African countries.

BACKGROUND: Escalation in the global rates of labour interventions, particularly cesarean section and oxytocin augmentation, has renewed interest in a better understanding of natural labour progression. Methodological advancements in statistical and computational techniques addressing the limitations of pioneer studies have led to novel findings and triggered a re-evaluation of current labour practices. As part of the World Health Organization's Better Outcomes in Labour Difficulty (BOLD) project, which aimed to develop a new labour monitoring-to-action tool, we examined the patterns of labour progression as depicted by cervical dilatation over time in a cohort of women in Nigeria and Uganda who gave birth vaginally following a spontaneous labour onset. METHODS AND FINDINGS: This was a prospective, multicentre, cohort study of 5,606 women with singleton, vertex, term gestation who presented at ≤ 6 cm of cervical dilatation following a spontaneous labour onset that resulted in a vaginal birth with no adverse birth outcomes in 13 hospitals across Nigeria and Uganda. We independently applied survival analysis and multistate Markov models to estimate the duration of labour centimetre by centimetre until 10 cm and the cumulative duration of labour from the cervical dilatation at admission through 10 cm. Multistate Markov and nonlinear mixed models were separately used to construct average labour curves. All analyses were conducted according to three parity groups: parity = 0 (n = 2,166), parity = 1 (n = 1,488), and parity = 2+ (n = 1,952). We performed sensitivity analyses to assess the impact of oxytocin augmentation on labour progression by re-examining the progression patterns after excluding women with augmented labours. Labour was augmented with oxytocin in 40% of nulliparous and 28% of multiparous women. The median time to advance by 1 cm exceeded 1 hour until 5 cm was reached in both nulliparous and multiparous women. Based on a 95th percentile threshold, nulliparous women may take up to 7 hours to progress from 4 to 5 cm and over 3 hours to progress from 5 to 6 cm. Median cumulative duration of labour indicates that nulliparous women admitted at 4 cm, 5 cm, and 6 cm reached 10 cm within an expected time frame if the dilatation rate was ≥ 1 cm/hour, but their corresponding 95th percentiles show that labour could last up to 14, 11, and 9 hours, respectively. Substantial differences exist between actual plots of labour progression of individual women and the 'average labour curves' derived from study population-level data. Exclusion of women with augmented labours from the study population resulted in slightly faster labour progression patterns. CONCLUSIONS: Cervical dilatation during labour in the slowest-yet-normal women can progress more slowly than the widely accepted benchmark of 1 cm/hour, irrespective of parity. Interventions to expedite labour to conform to a cervical dilatation threshold of 1 cm/hour may be inappropriate, especially when applied before 5 cm in nulliparous and multiparous women. Averaged labour curves may not truly reflect the variability associated with labour progression, and their use for decision-making in labour management should be de-emphasized.

Cervical dilatation patterns of 'low-risk' women with spontaneous labour and normal perinatal outcomes: a systematic review.

BACKGROUND: The call for women-centred approaches to reduce labour interventions, particularly primary caesarean section, has renewed an interest in gaining a better understanding of natural labour progression. OBJECTIVE: To synthesise available data on the cervical dilatation patterns during spontaneous labour of 'low-risk' women with normal perinatal outcomes. SEARCH STRATEGY: PubMed, EMBASE, CINAHL, POPLINE, Global Health Library, and reference lists of eligible studies. SELECTION CRITERIA: Observational studies and other study designs. DATA COLLECTION AND ANALYSIS: Two authors extracted data on: maternal characteristics; labour interventions; the duration of labour centimetre by centimetre; and the duration of labour from dilatation at admission through to 10 cm. We pooled data across studies using weighted medians and employed the Bootstrap-t method to generate the corresponding confidence bounds. MAIN RESULTS: Seven observational studies describing labour patterns for 99 971 women met our inclusion criteria. The median time to advance by 1 cm in nulliparous women was longer than 1 hour until a dilatation of 5 cm was reached, with markedly rapid progress after 6 cm. Similar labour progression patterns were observed in parous women. The 95th percentiles for both parity groups suggest that it was not uncommon for some women to reach 10 cm, despite dilatation rates that were much slower than the 1-cm/hour threshold for most part of their first stage of labours. CONCLUSION: An expectation of a minimum cervical dilatation threshold of 1 cm/hour throughout the first stage of labour is unrealistic for most healthy nulliparous and parous women. Our findings call into question the universal application of clinical standards that are conceptually based on an expectation of linear labour progress in all women. FUNDING: UNDP/UNFPA/UNICEF/WHO/World Bank Special Programme of Research, Development and Research Training in Human Reproduction (HRP), Department of Reproductive Health and Research, World Health Organization, and the United States Agency for International Development (USAID). TWEETABLE ABSTRACT: Cervical dilatation threshold of 1 cm/hour throughout labour is unrealistic for most women, regardless of parity.

Cervical dilatation over time is a poor predictor of severe adverse birth outcomes: a diagnostic accuracy study.

OBJECTIVE: To assess the accuracy of the World Health Organization (WHO) partograph alert line and other candidate predictors in the identification of women at risk of developing severe adverse birth outcomes. DESIGN: A facility-based, multicentre, prospective cohort study. SETTING: Thirteen maternity hospitals located in Nigeria and Uganda. POPULATION: A total of 9995 women with spontaneous onset of labour presenting at cervical dilatation of ≤6 cm or undergoing induction of labour. METHODS: Research assistants collected data on sociodemographic, anthropometric, obstetric, and medical characteristics of study participants at hospital admission, multiple assessments during labour, and interventions during labour and childbirth. The alert line and action line, intrapartum monitoring parameters, and customised labour curves were assessed using sensitivity, specificity, positive and negative likelihood ratios, diagnostic odds ratio, and the J statistic. OUTCOMES: Severe adverse birth outcomes. RESULTS: The rate of severe adverse birth outcomes was 2.2% (223 women with severe adverse birth outcomes), the rate of augmentation of labour was 35.1% (3506 women), and the caesarean section rate was 13.2% (1323 women). Forty-nine percent of women in labour crossed the alert line (4163/8489). All reference labour curves had a diagnostic odds ratio ranging from 1.29 to 1.60. The J statistic was less than 10% for all reference curves. CONCLUSIONS: Our findings suggest that labour is an extremely variable phenomenon, and the assessment of cervical dilatation over time is a poor predictor of severe adverse birth outcomes. The validity of a partograph alert line based on the 'one-centimetre per hour' rule should be re-evaluated. FUNDING: Bill & Melinda Gates Foundation, United States Agency for International Development (USAID), UNDP/UNFPA/UNICEF/WHO/World Bank Special Programme of Research, Development and Research Training in Human Reproduction (HRP), and WHO (A65879). TWEETABLE ABSTRACT: The alert line in check: results from a WHO study.

Cervical Dilatation Curves of Spontaneous Deliveries in Pregnant Japanese Females.

Background: Although cervical dilatation curves are crucial for appropriate management of labor progression, abnormal labor progression and obstetric interventions were included in previous and widely-used cervical dilatation curves. We aimed to describe the cervical dilatation curves of normal labor progression in pregnant Japanese females without abnormal labor progression and obstetric interventions. Methods: We completed retrospective obstetric record reviews on 3172 pregnant Japanese females (parity = 0, n = 1047; parity = 1, n = 1083; parity ≥ 2, n = 1042), aged 20 to 39 years old at delivery, with pregravid body mass indices of less than 30. All patients underwent spontaneous deliveries with term, singleton, cephalic and live newborns of appropriate-for-gestational age birthweight, without adverse neonatal outcomes. We characterized labor progression patterns by examining the relationship between elapsed times from the full dilatation and cervical dilatation stages, and labor durations by examining the distribution of time intervals from one cervical dilatation stage, to the next, and ultimately to the full dilatation. Results: Fastest cervical changes occurred at 6 cm (primiparas) and 5 cm (multiparas) of dilatation. The 95%tile of labor progression took over 3 hours to progress from 6 cm to 7 cm (primiparas), and over 2 hours to progress from 5 cm to 6 cm (multiparas). The 5%tile of traverse time to the full dilatation, during the active phase, was less than 1 hour (primiparas) and 0.5 hours (multiparas). At the end of the active phase, no deceleration phase was observed. Conclusions: Active labor may not start until 5 cm of dilatation. At the beginning of the active phase, cervical dilatation was slower than previously described. These results may reduce opportunities for obstetric interventions during labor progression.

Comparison of effacement curve with dilatation curve for prediction of labor progression.

AIM: This study was conducted to evaluate the ability of the effacement curve to predict fetal descent by comparing it to dilatation in order to improve the accuracy of the current partogram. METHOD: We conducted an observational study of women who were admitted for vaginal delivery at Mobini Hospital, Sabzevar, Iran in 2015. During labor, dilatation and effacement were plotted in different graphs and then their association with fetal descent was separately evaluated and compared. This assessment was performed in two groups: primipara and multipara. RESULTS: From 1750 individuals, 503 primiparous and 512 multiparous women were eligible for the study. An adjusted generalized estimating equations multivariable model showed both dilatation and effacement had a significant relationship with fetal descent either in primipara or multipara. In primipara, the prediction value of effacement equalled dilatation (ß,eff 0.29, P < 0.001; ß,dil 0.30, P < 0.001). In multipara, the prediction value of effacement was obviously higher than dilatation (ß,eff 0.45, P < 0.001; ß,dil 0.27, P < 0.001). The strength of effacement to predict labor in multipara was clearly greater than in primipara (ß,eff 0.45 and ß,eff 0.29, respectively). The strength of dilatation to predict labor in multipara was comparable to primipara (ß,dil 0.27 and ß,dil: 0.30, respectively). CONCLUSIONS: Regarding the acceptable predictive value of effacement, we believe considering effacement, dilatation and station curves altogether can improve the power of the existing partogram for the assessment of labor progression and detection of failure to progress.