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.
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.
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.
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.
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.

Laser vaporization of the cervix is an established method of treating cervical intra-epithelial neoplasia, but its effect on subsequent pregnancies remains controversial. The aim of this study was to investigate pregnancy outcomes after laser vaporization.
We conducted a retrospective study involving women who delivered live singletons between 2012 and 2019 in a tertiary hospital. The risks of adverse pregnancy outcomes after laser vaporization of the cervix were assessed using a multivariate regression model. The primary outcome was the adjusted odds ratio for preterm births. We also evaluated the course of labor progression, duration of labor, risk of emergency cesarean deliveries, and the risk of cervical laceration as secondary outcomes.
In total, 3359 women were analyzed in this study. The risk of preterm birth was significantly higher in pregnancies after laser vaporization of the cervix (adjusted odds ratio [AOR] 1.84, 95% confidence interval [95% CI] 1.06-3.20; p = 0.030). The duration of the first stage of labor was significantly shorter in the post-treatment group (median 255 min vs. 355 min; p = 0.0049). We did not observe significant differences in the duration of the second stage of labor (median 21 min vs 20 min; p = 0.507) or the rates of other obstetric events, including emergency cesarean deliveries (AOR 0.736; 95% CI 0.36-1.50; p = 0.400) and cervical laceration (AOR 0.717; 95% CI 0.22-2.35; p = 0.582).
Laser vaporization of the cervix is associated with an increased risk of preterm births and a shorter duration of the first stage of labor in subsequent pregnancies. Careful consideration is necessary when selecting a method of treatment for the uterine cervix of patients wishing future pregnancies.

Objectives Short interpregnancy intervals (IPI) have been linked to multiple adverse maternal and neonatal outcomes, but less is known about prolonged IPI, including its relationship with labor progression. The objective of the study was to investigate whether prolonged IPIs are associated with longer second stages of labor. Methods A perinatal database from Kaiser Permanente Hawaii was used to identify 442 women with a prolonged IPI ≥60 months. Four hundred forty two nulliparous and 442 multiparous women with an IPI 18-59 months were selected as comparison groups. The primary outcome was second stage of labor duration. Perinatal outcomes were compared between these groups. Results The median (IQR) second stage of labor duration was 76 (38-141) min in nulliparous women, 15 (9-28) min in multiparous women, and 18 (10-38) min in women with a prolonged IPI (p<0.0001). Pairwise comparisons revealed significantly different second stage duration in the nulliparous group compared to both the multiparous and prolonged IPI groups, but no difference between the multiparous and prolonged IPI groups. There was a significant association with the length of the IPI; median duration 30 (12-61) min for IPI ≥120 months vs. 15 (9-27) min for IPI 18-59 months and 16 (9-31) min for IPI 60-119 months (p=0.0014). Conclusions The second stage of labor did not differ in women with a prolonged IPI compared to normal multiparous women. Women with an IPI ≥120 months had a significantly longer second stage vs. those with a shorter IPI. These findings provide a better understanding of labor progression in pregnancies with a prolonged IPI.

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.
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.
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.
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.

We conducted a cross-sectional, descriptive, qualitative study, set in a postpartum unit, of 21 nulliparous women who spontaneously went into term labor at home. Our aim was to characterize symptoms of labor onset and progression to active labor before hospital admission for childbirth. The most frequent symptoms reported at labor onset were contractions, pain, ruptured membranes, cramping, and feelings of nervousness and excitement. Women reported that as labor progressed to the active phase, their pain increased, length and strength of contractions increased, and labor symptoms became more difficult to tolerate. Women\'s descriptions of symptoms of labor onset can aid the development of criteria to help women identify active labor and support decisions about timing of hospital admission for childbirth.

Epidural analgesia (EA) is one of the methods of choice for labor pain relief, but its adverse effects on the mother and child remain controversial. The objective of this study was to determine whether there is an association between the use of EA and different aspects of labor. The author(s) analyzed the effect of EA on different aspects of labor in a retrospective cohort observational study of deliveries in a public Spanish hospital during a 3-year period. Women with EA administration were found to increase the risk of stimulated labor, reduce the percentage of spontaneous deliveries, increase the risk of instrumental labor due to stalled labor or loss of fetal well-being, and increase the percentage of episiotomies. However, women with EA were not and increased risk for perineal laceration or the condition of the membranes at the delivery or with the type of placental expulsion. Thus, the administration of EA should be assessed in each case by the health care professional.

BACKGROUND: Labor that progresses faster than anticipated may lead to unplanned out-of-hospital births. With the aim to improve planning of transportation to birthing institutions, this study investigated predictors of time to completion for the first stage of labor conditional on cervical opening (conditional time) in multiparous women at term.
METHODS: We performed a retrospective analysis of partograms for women in Robson\'s group 3 who delivered at one hospital from 2003 to 2013. A generalized additive mixed model was fitted, accounting for possible non-linear relationships between the predictor variables and outcome, e.g. the time from each cervical measurement to full dilation, using multiple measurements for each woman. The following predictors were included: cervical dilation (cm), parity (1, 2, or ≥3 previous vaginal births), oxytocin infusion (no/yes), epidural (no/yes), maternal age (years), maternal height (cm), body mass index (BMI, kg/m2), birthweight (kg), spontaneous rupture of membranes (no/yes). A modified regression model with gestational age (days) instead of birthweight was used to predict conditional time to full cervical dilation for combinations of the most relevant predictors.
RESULTS: A total of 1753 partograms were included in the analysis. The strongest predictors were birthweight, epidural and oxytocin use, and spontaneous rupture of membranes, along with cervical measurements. For birthweight, there was an almost 40% increase in time to full cervical dilation for each 1-kg increment. Conditional time was on average 23% longer in cases with epidural use and 53% longer in cases requiring oxytocin augmentation. Spontaneous rupture of the membranes shortened conditional time by 31%. Maternal age was not associated with the outcome, while increasing BMI and parity modestly reduced conditional time.
CONCLUSIONS: Higher parity, lower fetal weight (gestational age), and spontaneous rupture of the membranes are associated with more rapid labor.

OBJECTIVE: Recent developments in transperineal ultrasound imaging of the pelvis have prompted trials to objectively evaluate labor progression for labor management. We evaluated the accuracy of transperineal ultrasound in diagnosing arrest of labor.
METHODS: Transperineal ultrasound and digital pelvic examinations were performed simultaneously in 63 term laboring patients (singleton fetuses in cephalic presentation). We analyzed a total of 216 ultrasound images (Sonography Volume Computer Aided Display Labor [Sono VCAD Labor®] installed in Voluson E8 ultrasound). We examined the correlation between the three ultrasound parameters head direction (HD), progression distance (PD), and progression angle (PA), and digital pelvic examination findings during labor in a transvaginal delivery group and an arrested labor group.
RESULTS: The coefficient of correlations between HD/PD/PA and cervical dilation/fetal station were 0.667/0.657/0.706 and 0.667/0.751/0.803, respectively. The three parameters had strong correlations with digital pelvic examination (P < 0.05). In the 11 cases (17%) of cesarean section due to arrested labor, the position of the fetal head was visually unchanged on sequential ultrasound images. According to receiver operating characteristic curves, the significant cut-offs for HD, PD, and PA for arrested labor were 105° (P = 0.048), 35 mm (P = 0.048), and 120° (P = 0.001), respectively.
CONCLUSIONS: Transperineal ultrasound imaging is helpful for objective evaluation of labor progression and the diagnosis of arrested labor.