Differences in outcomes between cesarean section in the second versus the first stages of labor

Risk factors for relaparotomy after a cesarean delivery: a case-control study

BACKGROUND

Relaparotomy following a cesarean delivery (CD) is an infrequent complication, with inconsistency regarding risk factors and indications for its occurrence. We therefore aimed to determine risk factors and indications for a relaparotomy following a CD at a single large tertiary center.

METHODS

A retrospective case-control single-center study (2013-2023). We identified all women who had a relaparotomy up to six weeks following a CD (study group). Maternal characteristics, obstetrical and surgical data were compared to a control group in a 1:2 ratio. Controls were women with a CD before and immediately after each case in the study group, who did not undergo a relaparotomy. Included were CDs occurring after 24 gestational weeks. CD performed at different centers and indications for repeat surgery unrelated to the primary surgery (e.g., appendicitis) were excluded. Logistic regression was used to adjust for potential confounders.

RESULTS

During the study period, 131,268 women delivered at our institution. Of them, 28,280 (21.5%) had a CD, and 130 patients (0.46%) underwent a relaparotomy. Relaparotomies following a CD occurred during the first 24 h, the first week, and beyond the first week, in 59.2%, 33.1%, and 7.7% of cases, respectively. In the multivariable logistic regression analysis, relaparotomy was significantly associated with Mullerian anomalies (aOR 3.33, 95%CI 1.08-10.24, p = 0.036); uterine fibroids (aOR 3.17, 95%CI 1.11-9.05,p = 0.031); multiple pregnancy (aOR 4.1, 95%CI 1.43-11.79,p = 0.009); hypertensive disorders of pregnancy (aOR 3.46, 95%CI 1.29-9.3,p = 0.014); CD during the second stage of labor (aOR 2.54, 95%CI 1.15-5.88, p = 0.029); complications during CD (aOR 1.62, 95%CI 1.09-3.21,p = 0.045); and excessive bleeding during CD or implementation of bleeding control measures (use of tranexamic acid, a hemostatic agent, or a surgical drain) (aOR 2.23, 95%CI 1.29-4.12,p = 0.012). Indications for relaparotomy differed depending on the time elapsed from the CD, with suspected intra-abdominal bleeding (36.1%) emerging as the primary indication within the initial 24 h.

CONCLUSION

We detected several pregnancy, intrapartum, and intra-operative risk factors for the need for relaparotomy following a CD. Practitioners may utilize these findings to proactively identify women at risk, thereby potentially reducing their associated morbidity.

The association between unintended hysterotomy extensions with cesarean delivery and subsequent preterm birth

BACKGROUND

An increased risk for preterm birth has been observed among individuals with a previous second stage cesarean delivery when compared with those with a previous vaginal delivery. One mechanism that may contribute to the increased risk for preterm birth following a second stage cesarean delivery is the increased risk for cervical injury because of extension of the uterine incision (hysterotomy) into the cervix. The contribution of hysterotomy extension to the rate of preterm birth in a subsequent pregnancy has not been investigated and may shed light on the mechanism underlying the observed relationship between the mode of delivery and subsequent preterm birth.

OBJECTIVE

We aimed to quantify the association between unintended hysterotomy extension and preterm birth in a subsequent delivery.

STUDY DESIGN

We performed a retrospective cohort study using electronic perinatal data collected from 2 university-affiliated obstetrical centers. The study included patients with a primary cesarean delivery of a term, singleton live birth and a subsequent singleton birth in the same catchment (2005-2021). The primary outcome was subsequent preterm birth <37 weeks' gestation; secondary outcomes included subsequent preterm birth at <34, <32, and <28 weeks' gestation. We assessed crude and adjusted associations between unintended hysterotomy extensions and subsequent preterm birth with log binomial regression models using rate ratios and 95% confidence intervals. Adjusted models included several characteristics of the primary cesarean delivery such as maternal age, length of active labor, indication for cesarean delivery, chorioamnionitis, and maternal comorbidity.

RESULTS

A total 4797 patients met the study inclusion criteria. The overall rate of unintended hysterotomy extension in the primary cesarean delivery was 6.0% and the total rate of preterm birth in the subsequent pregnancy was 4.8%. Patients with an unintended hysterotomy extension were more likely to have a longer duration of active labor, chorioamnionitis, failed vacuum delivery attempt, second stage cesarean delivery, and persistent occiput posterior position of the fetal head in the primary cesarean delivery and higher rates of smoking in the subsequent pregnancy. Multivariable analyses that controlled for several confounders showed that a history of hysterotomy extension was not associated with a higher risk for preterm birth <37 weeks' gestation (adjusted rate ratio, 1.55; 95% confidence interval, 0.98-2.47), but it was associated with preterm birth <34 weeks' gestation (adjusted rate ratio, 2.49; 95% confidence interval, 1.06-5.42).

CONCLUSION

Patients with a uterine incision extension have a 2.5 times higher rate of preterm birth <34 weeks' gestation when compared with patients who did not have this injury. This association was not observed for preterm birth <37 weeks' gestation. Future research should aim to replicate our analyses with incorporation of additional data to minimize the potential for residual confounding.

Unintended uterine extension at the time of cesarean delivery - risk factors and associated adverse maternal and neonatal outcomes

OBJECTIVE

To identify risk factors, maternal and neonatal adverse outcomes related to unintended lower segment uterine extension during cesarean delivery (CD).

METHODS

A retrospective cohort analysis in a single, university-affiliated medical center between 1 January 2018 and 31 December 2019. All singleton pregnancies delivered by CD were included. Univariate and multivariate analyses were performed to identify maternal and obstetrical predictors for uterine extension during CD. For secondary outcomes, we assessed the correlation between uterine extension and any adverse maternal or neonatal outcome. Risk factors were analyzed using ROC statistics to measure their prediction performance for a uterine extension.

RESULTS

Overall, 1746 (19.3%) CDs were performed during the study period. Of them, 121 (6.9%) CDs were complicated by unintended uterine extension. There was no difference in maternal demographics and clinical data stratified by uterine extension at CD. Uterine extensions were significantly more common following induction of labor, intrapartum fever, premature rupture of membranes, a trial of labor after cesarean, advanced gestational age, emergent CD, and in particular CD during the second stage of labor (37.2% vs. 6.5%) and after failed vacuum extraction (6.6% vs. 1.1%), p < .05 for all. The incidence of postpartum hemorrhage and re-laparotomy did not differ between the groups. Most of the extensions were caudal-directed (40.4%), and were closed by a two-layer closure (92%). Mean extension size was 4.5 ± 1.7 cm. Using multivariable analysis, the only factor that remained significant was CD at the second stage of labor (adjusted odds ratio (aOR) 54.2, 95% CI 4.5-648.9, p = .002), with an area under the ROC curve 0.653 (95% CI 0.595-0.712, p < .001). Emergent CD, body mass index, birth weight, failed vacuum attempt, and trial of labor after cesarean were not significant. For secondary outcomes, an unintended uterine extension was associated with longer operation time, higher estimated blood loss, greater pre- to post-CD hemoglobin difference, increased blood products transfusion, puerperal fever, and longer hospital stay. No clinically significant neonatal adverse outcomes were observed.

CONCLUSIONS

In our cohort, second-stage CD was the strongest predictor for an unintended uterine extension. Following uterine extension, women had increased infectious and blood-loss morbidity.

Association between the stage of labour during caesarean delivery with adverse maternal and neonatal outcomes among referred mothers to tertiary centres in resource-limited settings

OBJECTIVE

Although the caesarean delivery (CD) rate has substantially increased, little is known about its impacts when performed in the first and second stages of labour on fetomaternal outcomes, especially among referred mothers. Thus, this study aimed to investigate the association between CDs performed during the first and second stages of labour and poor maternal and neonatal outcomes among mothers referred to tertiary centres.

SETTING

This retrospective cohort study analysed medical records of mother-infant pairs from September 2020 to May 2023 in Southern Ethiopia.

PARTICIPANTS

We retrospectively collected data from 848 participants who underwent emergency CD on a referral basis during the study period.

PRIMARY OUTCOME MEASURE

The primary outcomes of interest were adverse maternal and neonatal outcomes. Data were analysed using descriptive and inferential statistics.

RESULTS

Of the 848 CDs, 722 (85.2%) and 126 (14.8%) were performed at the first and second stages of labour, respectively. Caesarean sections performed at the second stage were higher with nulliparity, increased maternal age, and birth weight. Compared with the first-stage CD, the second-stage CD was associated with a significantly increased risk of adverse maternal (OR 3.7, 95% CI 2.4 to 5.7) and neonatal outcomes (OR 2.0; 95% CI 1.3 to 2.9), including neonatal death.

CONCLUSION

Second-stage CDs have an increased risk of adverse maternal and neonatal outcomes. Strengthening and improving obstetric emergency surgical services and intensive neonatal care for those populations would help decrease the maternal and fetal negative consequences.

Utilizing machine learning to predict unplanned cesarean delivery

OBJECTIVE

To develop a comprehensive machine learning (ML) model predicting unplanned cesarean delivery (uCD) among singleton pregnancies based on features available at admission to labor.

METHODS

A retrospective cohort study from a tertiary medical center. Women with singleton vertex pregnancy of 34 weeks or more admitted for vaginal delivery between March 2011 and May 2019 were included. The cohort was divided into training (80%) and validation (20%) data sets. A separate cohort between June 2019 and April 2021 served as a test data set. Features selection was performed using a Random Forest ML algorithm.

RESULTS

The study population included 73 667 women, of which 4125 (6.33%) underwent uCD. The final model consisted of 13 features, based on prediction importance. The XGBoost model performed best with areas under the curve for the training, validation, and test data sets of 0.874, 0.839, and 0.840, respectively. The model showed a 65% positive predictive value for uCD among women in the 100th centile group, and a 99% or more negative predictive value in the less than 50th centile group. Positive and negative predictive values remained high among subgroups with high pretest probability of uCD.

CONCLUSION

An ML model for the prediction of uCD provides clinically useful risk stratification that remains accurate across gestational weeks 34-42 and among clinical risk groups. The model may be clinically useful for physicians and women admitted for labor.

SYNOPSIS

A machine learning model predicts unplanned cesarean delivery and can inform women's individualized decision making.

Evaluating the impact of a standardized induction protocol to reduce adverse perinatal outcomes: a prospective cohort study

OBJECTIVE

Our objective was to evaluate the impact of a standardized induction protocol on reducing maternal and neonatal morbidity in women undergoing an induction with an unfavorable cervix.

STUDY DESIGN

We performed a prospective cohort study of women undergoing an induction from May 2013 to June 2015. Women who were ≥18 years, ≥37 weeks with intact membranes and an unfavorable cervix (Bishop score of ≤6 and cervical dilation ≤2 cm) with no prior cesarean were included. We compared the following outcomes between women managed with the labor protocol versus women in an observation group, managed at the discretion of the provider: Labor length, cesarean delivery, maternal and neonatal morbidity, and neonatal intensive care unit admission for >48 hours. Multivariable models incorporated confounders specific to each outcome.

RESULTS

855 women were included (491: labor protocol group; 364: observational group). Women in the labor protocol group had a shorter time to delivery (15.7 hours vs. 18.0 hours, p < .001), a decrease in maternal morbidity (7.3% vs. 11.5%, p = .04), lower rates of NICU admission >48 hours (3.5% vs 8%, p = .005), and a lower neonatal morbidity (3.0% vs. 7.7%, p = .003) compared to women in the observational group. There was no difference in rate of cesarean between the labor protocol and observational groups (27.7% vs. 32.7%, p = .13). When adjusting for confounders, women in the labor protocol group had a 60% reduction in NICU admission >48 hours (RR: 0.41, 95% CI: 0.22-0.76) and a 70% reduction in neonatal morbidity (RR: 0.31, 95% CI: 0.13-0.70). Time to delivery and maternal morbidity were not significantly different in adjusted models.

CONCLUSION

Utilization of a standardized induction protocol was associated with a significant reduction in neonatal morbidity without increasing the risk of cesarean or maternal morbidity.

Transabdominal and transperineal ultrasound vs routine care before instrumental vaginal delivery - A randomized controlled trial

INTRODUCTION

The role of intrapartum ultrasound as an ancillary method to instrumental vaginal delivery is yet to be determined. This study aimed to compare the use of transabdominal and transperineal ultrasound with routine clinical care before performing an instrumental vaginal delivery, regarding the incidence of adverse maternal and neonatal outcomes.

MATERIAL AND METHODS

A randomized controlled trial was conducted between October 2016 and March 2019 in two tertiary care maternity hospitals in Lisbon, Portugal. Women at term, with full cervical dilatation, singleton fetuses in cephalic presentation, and with an established indication for instrumental vaginal delivery, were approached for enrollment. After informed consent was obtained, randomization into one of two groups was carried out. In the experimental arm, women underwent transabdominal ultrasound for determination of the fetal head position and transperineal ultrasound for evaluation of the angle of progression, before instrumental vaginal delivery. In the control arm, no ultrasound was carried out before instrumental vaginal delivery. Primary outcomes were composite measures of maternal and neonatal morbidity. Composite maternal morbidity consisted of severe postpartum hemorrhage, perineal trauma, and prolonged hospital stay. Composite neonatal morbidity consisted of low 5-minute Apgar score, umbilical artery metabolic acidosis, birth trauma, and neonatal intensive care unit admission.

RESULTS

A total of 222 women were enrolled (113 in the experimental arm and 109 in the control arm). No significant differences between the two arms were found in composite measures of maternal (23.9% in the experimental group vs 22.9% in the control group, odds ratio 1.055, 95% CI 0.567-1.964) or neonatal morbidity (9.7% in the experimental group vs 6.4% in the control group, odds ratio 1.571, 95% CI 0.586-4.215), nor in any of the individual outcomes.

CONCLUSIONS

In this small randomized controlled trial that was stopped for futility before reaching the required sample size, transabdominal and transperineal ultrasound performed just before instrumental vaginal delivery did not reduce the incidence of adverse maternal and neonatal outcomes, when compared with routine clinical care.

Real-time data analysis using a machine learning model significantly improves prediction of successful vaginal deliveries

BACKGROUND

The process of childbirth is one of the most crucial events in the future health and development of the offspring. The vulnerability of parturients and fetuses during the delivery process led to the development of intrapartum monitoring methods and to the emergence of alternative methods of delivery. However, current monitoring methods fail to accurately discriminate between cases in which intervention is unnecessary, partly contributing to the high rates of cesarean deliveries worldwide. Machine learning methods are applied in various medical fields to create personalized prediction models. These methods are used to analyze abundant, complex data with intricate associations to aid in decision making. Initial attempts to predict vaginal delivery vs cesarean deliveries using machine learning tools did not utilize the vast amount of data recorded during labor. The data recorded during labor represent the dynamic process of labor and therefore may be invaluable for dynamic prediction of vaginal delivery.

OBJECTIVE

We aimed to create a personalized machine learning-based prediction model to predict successful vaginal deliveries using real-time data acquired during the first stage of labor.

STUDY DESIGN

Electronic medical records of labor occurring during a 12-year period in a tertiary referral center were explored and labeled. Four different models were created using input from multiple maternal and fetal parameters. Initial risk assessments for vaginal delivery were calculated using data available at the time of admission to the delivery unit, followed by models incorporating cervical examination data and fetal heart rate data, and finally, a model that integrates additional data available during the first stage of labor was created.

RESULTS

A total of 94,480 cases in which a trial of labor was attempted were identified. Based on approximately 180 million data points from the first stage of labor, machine learning models were developed to predict successful vaginal deliveries. A model using data available at the time of admission to the delivery unit yielded an area under the curve of 0.817 (95% confidence interval, 0.811-0.823). Models that used real-time data increased prediction accuracy. A model that includes real-time cervical examination data had an initial area under the curve of 0.819 (95% confidence interval, 0.813-0.825) at first examination, which increased to an area under the curve of 0.917 (95% confidence interval, 0.913-0.921) by the end of the first stage. Adding the real-time fetal heart monitor data provided an area under the curve of 0.824 (95% confidence interval, 0.818-0.830) at first examination, which increased to an area under the curve of 0.928 (95% confidence interval, 0.924-0.932) by the end of the first stage. Finally, adding additional real-time data increased the area under the curve initially to 0.833 (95% confidence interval, 0.827-0.838) at the first cervical examination and up to 0.932 (95% confidence interval, 0.928-0.935) by the end of the first stage.

CONCLUSION

Real-time data acquired throughout the process of labor significantly increased the prediction accuracy for vaginal delivery using machine learning models. These models enable translation and quantification of the data gathered in the delivery unit into a clinical tool that yields a reliable personalized risk score and helps avoid unnecessary interventions.

Prediction of spontaneous vaginal delivery in nulliparous women with a prolonged second stage of labor: the value of intrapartum ultrasound

BACKGROUND

A limited number of studies have addressed the role of intrapartum ultrasound in the prediction of the mode of delivery in women with prolonged second stage of labor.

OBJECTIVE

The objective of the study was to evaluate the role of transabdominal and transperineal sonographic findings in the prediction of spontaneous vaginal delivery among nulliparous women with prolonged second stage of labor.

STUDY DESIGN

This was a 2-center prospective study conducted at 2 tertiary maternity units. Nulliparous women with a prolonged active second stage of labor, as defined by active pushing lasting more than 120 minutes, were eligible for inclusion. Transabdominal ultrasound to evaluate the fetal head position and transperineal ultrasound for the measurement of the midline angle, the head-perineum distance, and the head-symphysis distance were performed in between uterine contractions and maternal pushes. At transperineal ultrasound the angle of progression was measured at rest and at the peak of maternal pushing effort. The delta angle of progression was defined as the difference between the angle of progression measured during active pushing at the peak of maternal effort and the angle of progression at rest. The sonographic findings of women who had spontaneous vaginal delivery vs those who required obstetric intervention, either vacuum extraction or cesarean delivery, were evaluated and compared.

RESULTS

Overall, 109 were women included. Spontaneous vaginal delivery and obstetric intervention were recorded in 40 (36.7%) and 69 (63.3%) patients, respectively. Spontaneous vaginal delivery was associated with a higher rate of occiput anterior position (90% vs 53.2%, P < .0001), lower head-perineum distance and head-symphysis distance (33.2 ± 7.8 mm vs 40.1 ± 9.5 mm, P = .001, and 13.1 ± 4.6 mm vs 19.5 ± 8.4 mm, P < .001, respectively), narrower midline angle (29.6° ± 15.3° vs 54.2° ± 23.6°, P < .001) and wider angle of progression at the acme of the pushing effort (153.3° ± 19.8° vs 141.8° ± 25.7°, P = .02) and delta-angle of progression (17.3° ± 12.9° vs 12.5° ± 11.0°, P = .04). At logistic regression analysis, only the midline angle and the head-symphysis distance proved to be independent predictors of spontaneous vaginal delivery. More specifically, the area under the curve for the prediction of spontaneous vaginal delivery was 0.80, 95% confidence interval (0.69-0.92), P < .001, and 0.74, 95% confidence interval (0.65-0.83), P = .002, for the midline angle and for the head-symphysis distance, respectively.

CONCLUSION

Transabdominal and transperineal intrapartum ultrasound parameters can predict the likelihood of spontaneous vaginal delivery in nulliparous women with prolonged second stage of labor.