Normal labor curve in twin gestation.

BACKGROUND: Failure to progress is one of the leading indications for cesarean delivery in trials of labor in twin gestations. However, assessment of labor progression in twin labors is managed according to singleton labor curves. OBJECTIVE: This study aimed to establish a partogram for twin deliveries that reflects normal and abnormal labor progression and customized labor curves for different subgroups of twin labors. STUDY DESIGN: This was a multicenter, retrospective cohort analysis of twin deliveries that were recorded in 3 tertiary medical centers between 2003 and 2017. Eligible parturients were those with twin gestations at ≥34 weeks' gestation with cephalic presentation of the presenting twin and ≥2 cervical examinations during labor. Exclusion criteria were elective cesarean delivery without a trial of labor, major fetal anomalies, and fetal demise. The study group comprised twin gestations, whereas singleton gestations comprised the control group. Statistical analysis was performed using Python 3.7.3 and SPSS, version 27. Categorical variables were analyzed using chi-square tests. Student t test and Mann-Whitney U test were applied to analyze the differences in continuous variables, as appropriate. RESULTS: A total of 1375 twin deliveries and 142,659 singleton deliveries met the inclusion criteria. Duration of the active phase of labor was significantly longer in twin labors than in singleton labors in both nulliparous and multiparous parturients; the 95th percentile duration was 2 hours longer in nulliparous twin labors and >3.5 hours longer in multiparous twin labors than in singleton labors. The cervical dilation progression rate was significantly slower in twin deliveries than in singleton deliveries with a mean rate in twin deliveries of 1.89 cm/h (95th percentile, 0.51 cm/h) and a mean rate of 2.48 cm/h (95th percentile, 0.73 cm/h) in singleton deliveries (P<.001). In addition, epidural use further slowed labor progression in twin deliveries. The second stage of labor was also markedly longer in twin deliveries, both in nulliparous and multiparous women (95th percentile, 3.04 vs 2.83 hours, P=.002). CONCLUSION: Twin labors are characterized by a slower progression of the active phase and second stage of labor compared with singleton labors in nulliparous and multiparous parturients. Epidural analgesia further slows labor progression in twin labors. Implementation of these findings in clinical management might lower cesarean delivery rates among cases with protracted labor in twin gestations.

Spontaneous labor curve based on a retrospective multi-center study in Japan.

AIM: In Japan, the criteria of the latent and active phases of the first stage of labor have not been decided. The Japan Society of Obstetrics and Gynecology (JSOG) Perinatal Committee conducted a study to construct a spontaneous labor curve in order to determine the point of onset of the active phase. METHODS: The participants were women who had spontaneous deliveries at four health facilities in Japan between September 1, 2011, and September 31, 2019. Spontaneous delivery was defined as the spontaneous onset of labor at term (37 weeks, 0 days to 41 weeks, 6 days) with vaginal delivery of a mature fetus in a cephalic position without uterotonic agents or epidural analgesia. The time points for each "cm" of dilation were collected starting from the time of full dilation retrogradely. The relationship between time since labor onset and cervical dilation was expressed as a curve using a smoothing B-spline. RESULTS: A total of 4215 primiparous and 5266 multiparous women were included in this study. The spontaneous labor curve showed that in both primiparous and multiparous women, labor progress was slow until 5 cm cervical dilation, accelerating between 5 and 6 cm dilation, and steadily progressed after 6 cm dilation. CONCLUSION: We propose that the active phase of the first stage of labor be defined as starting at 5 cm dilation of the cervix, and that it be divided into an acceleration phase (5-6 cm dilation) and a maximal phase (>6 cm dilation).

Comparison of the labor curves with and without combined spinal-epidural analgesia in nulliparous women- a retrospective study.

BACKGROUND: Neuraxial labor analgesia is known to increase the rate of instrumental delivery and prolong the second stage of labor; however, there is no standard method to evaluate the progress of labor under analgesia. Friedman curve is considered the gold standard for evaluating the progress of labor. However, it included not only neuraxial labor analgesia but also labor without analgesia. Thus we compared the labor curves of primiparous women undergoing labor with and without neuraxial labor analgesia, to understand the progress of labor in both groups and to arrive at a standard curve to monitor the progress of labor under neuraxial analgesia. METHODS: Primiparous women with cephalic singleton pregnancies who delivered at term from 2016 to 2017 were included. Two hundred patients who opted for combined spinal-epidural (CSE) labor analgesia were included in the CSE group and 200 patients who did not undergo CSE were included in the non-CSE group. In all, 400 cases were examined retrospectively. The evaluation parameters were cervical dilation and fetal station, and we calculated the average value per hour to plot the labor curves. RESULTS: The labor curve of the non-CSE group was significantly different from the Friedman curve. In the CSE group, the time from 4 cm dilation of the cervix to full dilation was 15 h; in addition, the speed of cervical dilation was different from that in the non-CSE group. The progress of labor in the CSE group was faster than that in the non-CSE group during the latent phase; however, the progress in the CSE group was slower than that in the non-CSE group during the active phase. CONCLUSIONS: Neuraxial labor analgesia results in early cervical dilation and descent of the fetal head; thus, appropriate advance planning to manage the delivery may be essential.

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.

Labor patterns in Asian American women with vaginal birth and normal perinatal outcomes.

BACKGROUND: The pattern of normal labor progression can help to define prolonged labor and dystocia. Several studies had tried to establish the process of normal labor in different races. Previous findings in Asian women were limited and often incomparable. Our aim was to examine labor patterns in Asian American women. STUDY DESIGN: A total of 3079 women with singleton term gestation, vertex presentation, vaginal delivery, and a normal perinatal outcome were extracted from the Consortium on Safe Labor study. A repeated measure analysis and an interval-censored regression were applied to depict the average labor curves and estimate the time interval of cervical dilation by 1 cm, respectively. A sensitivity analysis was conducted to assess the impact of oxytocin augmentation. The cumulative duration of the 1st stage of labor was calculated to draw a partograph. RESULTS: It took an average of 5.2 hours for nulliparous Asian women with spontaneous labor onset to complete the 1st stage of labor, and the 95th centile was 14.4 hours. Labor progressed at a similar rate between nulliparous and multiparous women before 6 cm. Afterward, multiparous women progressed noticeably faster than nulliparous women. The differences in labor duration between women with and without oxytocin augmentation were <0.5 hour for both nulliparous and multiparous women. CONCLUSIONS: A new partograph that restricted the diagnosis of dystocia to the slowest 5% of nulliparous women with normal perinatal outcomes was proposed. The labor pattern in Asian American women was similar to that of the overall United States population.

Labor progression of women attempting vaginal birth after previous cesarean delivery with or without epidural analgesia.

PURPOSE: Normal labor curves have not been assessed for women undergoing a trial of labor after cesarean delivery (TOLAC). This study examined labor patterns during TOLAC in relation to epidural analgesia use. METHODS: Retrospective cohort study of deliveries of women undergoing TOLAC at a single, academic, tertiary medical center. Length of first, second and third stages of labor was compared between 424 women undergoing TOLAC in the current labor with no previous vaginal delivery (VD) and 357 women with at least one previous VD and current TOLAC. RESULTS: Women in the TOLAC only group had significantly longer labors compared to women in the previous VD and TOLAC group. In both groups, women who underwent epidural analgesia had longer first and second stages of labor. In the TOLAC only group, more women who had epidural analgesia tended to deliver vaginally as compared to those who did not (P = 0.09). For women who delivered vaginally, the 95th percentile for the second stage duration with epidural was 3.40 h in the TOLAC only group and 2.3 h in the previous VD and TOLAC group. The 95th percentile for the second stage duration without epidural was 1.4 h in the TOLAC only group and 0.9 h in the previous VD and TOLAC group. CONCLUSIONS: Operative intervention (instrumental delivery/cesarean delivery (CD)) might be considered for women attempting TOLAC after a 2-h duration of second stage without epidural and 3-h duration with epidural, with an hour less for women who also had previous VD.

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.

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.

Impact factors on cervical dilation rates in the first stage of labor.

AIMS: To assess cervical dilation rates of nulliparous and multiparous women in the active first stage of labor and to evaluate significant impact factors. METHODS: In a retrospective cohort study between January 2007 and July 2014 at the University Hospital of Zurich in Switzerland, we analyzed 8378 women with singleton pregnancies in vertex presentation with a vaginal delivery at 34+0 to 42+5 gestational weeks. Median cervical dilation rates were calculated and different impact factors evaluated. RESULTS: Cervical dilation rates increase during labor progress with faster rates in multiparous compared with nulliparous women (P<0.001). Dilation rates exceed 1 cm/h at a dilatation of 6-7 cm, but are very individual. Accelerating impact factors are multiparity, a greater amount of cervical dilation and fetal occipitoanterior position, whereas the use of epidural anesthesia, a higher fetal weight and head circumference decelerate dilation (P<0.001). CONCLUSION: Cervical dilation is a hyperbolic increasing process, with faster dilation rates in multiparous compared to nulliparous women and a reversal point of labor around 6-7 cm, respectively. Besides, cervical dilation is highly individual and affected by several impact factors. The diagnosis of labor arrest or prolonged labor should therefore be based on such rates and on the individual evaluation of every woman.

Normal labor curve is affected by fetus gender: A cohort study.

Background: Fetal male gender may affect the progression of labor and could be a risk factor for labor arrest. This study was conducted to evaluate the effect of fetus gender on labor curve. Methods: In this cohort study, 1550 singleton term pregnant women in labor phase (either spontaneous or by induction) were enrolled. Results of regular cervical examination, dilation, length of labor stages, mode of delivery, and sex of the fetus, and birth weight were recorded for all participants. Labor progression curve was compared between two sex groups with independent t test and chi2 test. Results: Finally, 1527 women completed the study (47.8% female and 52.1% male). Mean duration from beginning of the active phase up to full dilatation, from 4 to 6 cm, 6 to 8 cm, and 8 to 10 cm dilatations, were significantly longer in the male sex group compared to the female (p˂0.05). All durations were also significantly different when parity was considered (p˂0.05). We could not show fetal sex as an independent risk factor for active phase arrest (OR Adjusted: 1.18, CI 95% 1.01:1.42). Conclusion: Active phase stage was slower and longer in women who carried male fetuses compared to those carrying female fetuses; however, fetal sex did not increase the risk of active phase arrest.

Preterm induction of labor: predictors of vaginal delivery and labor curves.

OBJECTIVE: The purpose of this study was to evaluate the labor curves of patients who undergo preterm induction of labor (IOL) and to assess possible predictors of vaginal delivery (VD). STUDY DESIGN: Data from the National Institute of Child Health and Human Development Consortium on Safe Labor were analyzed. A total of 6555 women who underwent medically indicated IOL at <37 weeks of gestation were included in this analysis. Patients were divided into 4 groups based on gestational age (GA): group A, 24-27+6 weeks; B, 28-30+6 weeks; C, 31-33+6 weeks; and D, 34-36+6 weeks. Pregnant women with a contraindication to VD, IOL ≥37 weeks of gestation, and without data from cervical examination on admission were excluded. Analysis of variance was used to assess differences between GA groups. Multiple logistic regression was used to assess predictors of VD. A repeated measures analysis was used to determine average labor curves. RESULTS: Rates of vaginal live births increased with GA, from 35% (group A) to 76% (group D). Parous women (odds ratio, 6.78; 95% confidence interval, 6.38-7.21) and those with a favorable cervix at the start of IOL (odds ratio, 2.35; 95% confidence interval, 2.23-2.48) were more likely to deliver vaginally. Analysis of labor curves in nulliparous women showed shorter duration of labor with increasing GA; the active phase of labor was, however, similar across all GAs. CONCLUSION: Most women who undergo medically indicated preterm IOL between 24 and 36+6 weeks of gestation deliver vaginally. The strongest predictor of VD was parity. Preterm IOL had a limited influence on estimated labor curves across GAs.

Misguided guidelines for managing labor.

In a recent review we expressed concerns about new guidelines for the assessment and management of labor recommended jointly by the American Congress of Obstetricians and Gynecologists (ACOG) and the Society for Maternal-Fetal Medicine (SMFM). These guidelines are based heavily on a new concept of how cervical dilatation and fetal descent progress, derived from the work of Zhang et al. In their Viewpoint article they have addressed, but not allayed, the concerns we described in our review. We assert that the dilatation curve promulgated by Zhang et al cannot be reconciled with direct clinical observation. Even if they were correct, however, it still does not follow that the ACOG/SMFM guidelines should recommend replacing the coherent system of identifying and managing labor aberrations described by Friedman. That system is grounded in well-established clinical principles based on decades of use and the objectively documented association of some labor abnormalities with poor fetal and maternal outcomes. Recommendations for new clinical management protocols should require the demonstration of superior outcomes through extensive, preferably prospective, assessment. Using untested guidelines for the management of labor may adversely affect women and children. Even if those guidelines were to reduce the currently excessive cesarean delivery rate, the price of that benefit is likely to be a trade-off in harm to parturients and their offspring. The nature and degree of that harm needs to be documented before considering adoption of the guidelines.

Statistical aspects of modeling the labor curve.

In a recent review by Cohen and Friedman, several statistical questions on modeling labor curves were raised. This article illustrates that asking data to fit a preconceived model or letting a sufficiently flexible model fit observed data is the main difference in principles of statistical modeling between the original Friedman curve and our average labor curve. An evidence-based approach to construct a labor curve and establish normal values should allow the statistical model to fit observed data. In addition, the presence of the deceleration phase in the active phase of an average labor curve was questioned. Forcing a deceleration phase to be part of the labor curve may have artificially raised the speed of progression in the active phase with a particularly large impact on earlier labor between 4 and 6 cm. Finally, any labor curve is illustrative and may not be instructive in managing labor because of variations in individual labor pattern and large errors in measuring cervical dilation. With the tools commonly available, it may be more productive to establish a new partogram that takes the physiology of labor and contemporary obstetric population into account.

Perils of the new labor management guidelines.

Recent guidelines issued jointly by the American College of Obstetricians and Gynecologists and the Society for Maternal-Fetal Medicine for assessing labor progress differ substantially from those described initially by Friedman, which have guided clinical practice for decades. The guidelines are based on results obtained from new and untested methods of analyzing patterns of cervical dilatation and fetal descent. Before these new guidelines are adopted into clinical practice, the results obtained by these unconventional analytic approaches should be validated and shown to be superior, or at least equivalent, to currently accepted standards. The new guidelines indicate the patterns of labor originally described by Friedman are incorrect and, further, are inapplicable to modern obstetric practice. We contend that the original descriptions of normal and abnormal labor progress, which were based on direct clinical observations, accurately describe progress in dilatation and descent, and that the differences reported more recently are likely attributable to patient selection and the potential inaccuracy of very high-order polynomial curve-fitting methods. The clinical evaluation of labor is a process of serially estimating the likelihood of a safe vaginal delivery. Because many factors contribute to that likelihood, such as cranial molding, head position and attitude, and the bony architecture and capacity of the pelvis, graphic labor patterns should never be used in isolation. The new guidelines are based heavily on unvalidated notions of labor progress and ignore clinical parameters that should remain cornerstones of intrapartum decision-making.

Progression of cervical dilatation in normal human labor is unpredictable.

INTRODUCTION: The aim of this study was to analyze how the progression of cervical dilatation in active labor can be predicted by digital assessment in low-risk pregnant women, in spontaneous labor at term. MATERIAL AND METHODS: This prospective observational study was performed on 328 women with singleton term gestations experiencing midwife-led labor according to local protocols, progressing to full dilatation and spontaneous delivery without any medical intervention. Mixed nonlinear models were adopted to (i) model individual cervical data into centile curves and (ii) calculate the time needed to gain 1 cm in cervical dilatation (TNG1cm ) modeled as a function of current dilatation. We correlated the first and the last TNG1cm on parturients with at least four cervical data points. RESULTS: TNG1cm showed large variations, both before and after 6 cm. This variability of natural progression of cervical curves described by the 10th and 90th centiles exceeded the differences observed in published curves from cohorts homogeneous for parity, weight and ethnicity. There was no significant correlation between the first and the last TNG1cm . Neonatal base excess was not significantly different in women with TNG1cm <10th centile and >90th centile. CONCLUSIONS: The rate of cervical dilatation, traced by parsimonious nonlinear mixed models, is largely unpredictable in the case of spontaneous naturally progressing labor, even when possible larger individual variability is excluded by prudent clinical rules. Future research in labor and delivery should be focused on the diagnosis of the causes that lie behind apparently erratic cervical changes.

Partogram of Grandmultiparous Parturients: A Multicenter Cohort Study.

Sparse and conflicting data exist regarding the normal partogram of grand-multiparous (GMP, defined as parity of 6+) parturients. Customized partograms may potentially lower cesarean delivery rates for protraction disorders in this population. In this study, we aim to construct a normal labor curve of GMP women and compare it to the multiparous (MP, defined as parity of 2-5) partogram. We conducted a multicenter retrospective cohort analysis of deliveries between the years 2003 and 2019. Eligible parturients were the trials of labor of singletons ≥37 + 0 weeks in cephalic presentation with ≥2 documented cervical examinations during labor. Exclusion criteria were elective cesarean delivery without a trial of labor, preterm labor, major fetal anomalies, and fetal demise. GMP comprised the study group while the MP counterparts were the control group. A total of 78,292 deliveries met the inclusion criteria, comprising 10,532 GMP and 67,760 MP parturients. Our data revealed that during the first stage of labor, cervical dilation progressed at similar rates in MPs and GMPs, while head descent was a few minutes faster in GMPs compared to MPs, regardless of epidural anesthesia. The second stage of labor was faster in GMPs compared to MPs; the 95th percentile of the second stage duration of GMPs (48 min duration) was 43 min less than that of MPs (91 min duration). These findings remained similar among deliveries with and without epidural analgesia or labor induction. We conclude that GMPs' and MPs' cervical dilation progression in the active phase of labor was similar, and the second stage of labor was shorter in GMPs, regardless of epidural use. Thus, GMPs' uterus function during labor corresponds, and possibly surpasses, that of MPs. These findings indicate that health providers can use the standard partogram of the active phase of labor when caring for GMP parturients.

Is there a difference in labor patterns after induction with prostaglandins and double-balloon catheters?

BACKGROUND: Labor progression curves are believed to differ between spontaneous and induced labors. However, data describing labor progression patterns with different modes of induction are insufficient. OBJECTIVE: This study aimed to compare the progress patterns between labors induced with slow-release prostaglandin E2 vaginal analogue and those induced with a double-balloon catheter. STUDY DESIGN: This retrospective cohort study included all nulliparous women who delivered at term and who underwent cervical ripening with prostaglandin E2 vaginal analogue or a double-balloon catheter from 2013 to 2021 in a tertiary hospital in Israel. Included in the analysis were women who achieved 10 cm cervical dilatation. The time intervals between centimeter-to-centimeter changes were evaluated. RESULTS: A total of 1087 women were included of whom 786 (72.3%) were induced using prostaglandin E2 vaginal analogue and 301 (27.7%) were induced using a double-balloon catheter. The time from induction to birth was similar between the groups (32.5 hours for the prostaglandin E2 vaginal analogue group [5th-95th percentiles, 6.5-153.8] vs 29.2 hours for the double-balloon group [5th-95th percentiles, 9.1-157.1]; P=.100). The median time of the latent phase (2-6 cm dilation) was longer for the double-balloon catheter group than for the prostaglandin E2 vaginal analogue group (7.3 hours [5th-95th percentiles, 5.6-14.5] vs 6.0 hours [5th-95th percentiles, 2.4-18.8]; P=.042). The median time of active labor (6-10 cm dilatation) was similar between groups (1.9 hours [5th-95th percentiles, 0.3-7.4] for the prostaglandin E2 vaginal analogue group vs 2.3 hours [5th-95th percentiles, 0.3-6.5] for the double-balloon catheter group; P=.307). CONCLUSION: Deliveries subjected to cervical ripening with a double-balloon catheter were characterized by a slightly longer latent phase than deliveries induced by prostaglandin E2 vaginal analogue. After reaching the active phase of labor, the mode of cervical ripening did not influence the labor progress pattern.

Spontaneous labor patterns among women attempting vaginal birth after cesarean delivery.

OBJECTIVE: This study evaluated spontaneous labor patterns among women achieving a vaginal birth after cesarean (VBAC), without a previous vaginal delivery in relation to nulliparous women. METHODS: This historical cohort study included 422 women attempting VBAC and 150 nulliparas. We examined time intervals for each centimeter of cervical dilation and compared labor progression in 321 women who achieved spontaneous VBAC and 147 nulliparous women achieving a spontaneous vaginal delivery. Epidural anesthesia use, delivery mode, cord arterial pH and 5-minute Apgar score were also compared. FINDINGS: Women in the VBAC group compared to nulliparous women had similar durations of first (4-10 cm: 4:22 (00:54-13:10) h vs. 4:47 (1:10-15:10) h, p = .61), second (1:07 (8:00-3:21), vs. 1:34 (10:00-3:40), p = .124) and third stages of labor (10:00 (2:00-22:00) vs. 08:00 (3:24-22:12), p = .788). When comparing women who had epidural analgesia to those who did not, no differences were found between the groups regarding durations of first and second stages of labor. Interestingly, among parturients without epidural anesthesia only, the VBAC group had shorter second stage compared to the nulliparous (00:19 (0:04-1:59) vs. 00:47 (0:08-2:09), p = .023). CONCLUSION: Labor patterns among women achieving spontaneous VBAC are similar to those of nulliparous women with spontaneous vaginal deliveries.

Maternal and Neonatal Outcomes in Twin Deliveries with Prolonged Second-Stage Duration of the Presenting Twin: a Retrospective Cohort Study.

To assess the risk of adverse maternal and neonatal outcomes as a function of the presenting twin second-stage duration. A retrospective cohort study of deliveries taking place in an academic medical center between 2005 and 2019. The study group included women with twin pregnancies with the first fetus in vertex presentation, who attempted vaginal delivery with epidural analgesia and attained the second stage of labor. Prolonged second stage (PSS) was defined as when exceeding the 95th percentile of presenting twin second-stage duration recorded among all parturients who achieved spontaneous vaginal deliveries in our center during the study period, stratified by parity: 3 h in nulliparas and 1 h in multiparas. Women with and without PSS were compared. The primary outcome was a composite of adverse maternal outcomes. A univariate analysis was conducted and followed by multivariate analysis. During the study period, 1,337 parturients (36% of twin deliveries) met study criteria, of these 22% (298) were nulliparous and 78% (1,039) were multiparous. The second stage of labor of the presenting twin was prolonged in 41 (13.8%) of the nulliparas and 64 (6.2%) multiparas. Prolonged second stage was associated with episiotomy, chorioamnionitis, endometritis, and blood product transfusion, as well as vacuum deliveries of the first and second twin, second-stage cesarean, and a higher rate of composite adverse maternal outcome in nulliparous (41.5% vs. 20.2%, p<0.01) and with higher rates of episiotomy, postpartum hemorrhage, and vacuum deliveries of the first and second twin, but a similar rate of composite adverse maternal outcome in multiparous women (7.8% vs. 9.3%, p=0.68); moreover, the composite adverse neonatal outcome was not increased in nulliparous (36.6% vs. 38.5%, p=0.81) nor in multiparous women (21.9% vs. 23.6%, p=0.75). Prolonged second stage of labor of the presenting twin was associated with an adverse composite maternal outcome in nulliparous and with postpartum hemorrhage in multiparous. Further larger studies are warranted to reinforce our findings.

Process of fetal head descent as recorded by ultrasonography: How does this compare with the conventional first stage of labor?

OBJECTIVE: To construct an ultrasound partogram using serial transperineal sonographic measurements of the angle of fetal head progression during the first stage of labor, and to compare it with a conventional partogram based on digital vaginal examinations. METHODS: Between 2017 and 2018, a prospective cohort study at Drum Tower Hospital, Nanjing, China, recruited 375 nulliparous women with singleton pregnancy and spontaneous onset of labor at 37 or more gestational weeks. Transperineal ultrasound scans were performed to measure the angle of progression (AoP) every 0.5-1 h until the second stage. Vaginal examinations were also used to measure cervical dilatation. Repeated-measures analysis was used to generate labor curves. RESULTS: The labor curve generated by AoP had a pattern similar to that based on cervical dilatation. There was an initial slow period lasting approximately 5.5 h until the cervical dilatation or AoP reached the inflection point (4 cm and 119°, respectively), followed by a second, more rapid period, lasting approximately 2.5 h. CONCLUSION: Based on ultrasound data, it was feasible to construct an "angle of progression partogram" of the first stage of labor, which was similar in pattern to the partogram based on cervical dilatation measured in the same cohort.