[Caesarean section at full dilatation: What are the risks to fear for the mother and child?]

The Role of Passive Descent and Epidural Analgesia in Outcomes Associated With Prolonged Pushing Among Nulliparous Individuals in Midwifery Care

INTRODUCTION

Efforts to reduce primary cesarean birth may include supporting longer second stages of labor. Although midwifery-led care is associated with lower cesarean use, little has been published on associated outcomes of prolonged second stage (≥3 hours of pushing) for nulliparous individuals in US hospital-based midwifery care. Epidural analgesia and the role of passive descent in midwifery-led care are also underexplored in relation to the second stage. In this study, we report the incidence of prolonged second stage stratified by epidural analgesia and/or passive descent. Secondary aims included calculating the odds of cesarean birth, obstetric anal sphincter injury (OASI), postpartum hemorrhage (PPH), and neonatal complications.

METHODS

Data were collected prospectively from a single academic center in the United States from 2012 through 2019. Our cohort analysis of labors attended by midwives for nulliparous, term, singleton, and vertex pregnancies included both descriptive and inferential statistics comparing outcomes between prolonged versus nonprolonged pushing groups. We stratified the sample and quantified second stage outcomes by epidural analgesia and by use of passive descent.

RESULTS

Of the 1465 births, 17% (n = 247) included prolonged pushing. Cesarean ranged from 2.2% without prolonged pushing to 26.7% with prolonged pushing. Fetal malposition, epidural analgesia, and longer passive descent were more common among those with prolonged active pushing. Despite these factors, neither odds for PPH nor poor neonatal outcomes were associated with prolonged pushing. Those with more than one hour of passive descent in the second stage who also had prolonged active pushing had lower odds for cesarean but higher odds for OASI relative to those who had little passive descent before pushing for more than 3 hours.

DISCUSSION

Prolonged pushing occurred in nearly 2 of 10 nulliparous labors. Fetal malposition, epidural analgesia, and prolonged pushing were commonly observed with longer passive descent, cesarean, and OASI. Passive descent in these data likely reflects individualized midwifery care strategies when pushing was complicated by fetal malposition or other complexities.

Passive second stage of labor: Does a fourth hour increase maternal morbidity in nulliparous patients at term with epidural?

OBJECTIVES

Prolonging the passive second stage of labor could increase vaginal birth rate, but the data concerning maternal and fetal morbidity are contradictory. The French guidelines did not specify a maximum duration of the passive second stage. Our objective was to assess if allowing a 4th hour after full dilatation before pushing increased maternal morbidity, compared to 3 h after full dilatation.

STUDY DESIGN

This single-center, retrospective, observational cohort study took place from January 1-December 31, 2020, in a tertiary maternity unit. All consecutive term nulliparous women who delivered under epidural anesthesia and without pathological fetal heart rate and reaching a second-stage passive phase of labor lasting at least 3 h were included. We compared 2 groups according to the duration of the passive second stage: "3-hour group" and "4-hour group". In the "3-hour group," featuring a second-stage passive phase of up to 3 h, pushing is initiated for favorable conditions, while a cesarean section is performed if conditions are deemed unfavorable. In the "4-hour group", obstetric conditions not justifying immediate pushing after three hours, and the obstetric team believed that an additional hour of expectant management could lead to a successful vaginal delivery. The principal endpoint was a composite criterion of maternal morbidity including obstetric anal sphincter injuries, postpartum hemorrhage, transfusion and intrauterine infection.

RESULTS

We included 111 patients in the "4-hour group" and 349 in the "3-hour group". Composite maternal morbidity did not increase in the "4-hour group" compared to the "3-hour group" (21 (18.9 %) versus 61 (17.5 %); p = 0.73). Neonatal morbidity was similar between the two groups. In the "4-hour group, 91 (82 %) patients had vaginal deliveries", 62 (55,9 %) by spontaneous vaginal delivery and 29 (26,1 %) with instrumental assistance.

CONCLUSION

For selected patients, waiting for 4 h at full dilation can be beneficial due to the high rate of vaginal delivery and low incidence of maternal and fetal complications.

Is duration of passive second stage associated with a risk of hysterotomy extension during cesarean?

Objective

To assess obstetric factors associated with hysterotomy extension among women undergoing a second-stage cesarean.

Study design

This 5-year retrospective cohort study (2013–2017) included all women with second-stage cesarean deliveries of live-born singleton fetuses in cephalic presentation at term. It took place at a tertiary center that practices delayed pushing. We performed univariable and multivariable logistic regression to assess the maternal, obstetric, and neonatal factors associated with hysterotomy extension mentioned in the surgical report. Operative time, postpartum hemorrhage, and maternal complications were also studied.

Results

Of the 3350 intrapartum cesareans, 2637 were performed at term for singleton fetuses in cephalic presentation: 747 (28.3%) during the second stage of labor, 83 (11.1%) of which were complicated by a hysterotomy extension. The median duration of the passive phase of the second stage did not differ between women with and without an extension (164 min versus 160 min, P = 0.85). No other second-stage obstetric characteristics, i.e., duration of the active phase, fetal head station, or fetal malposition, were associated with the risk of extension. Factors significantly associated with extension were the surgeon’s experience and forceps use during the cesarean. Women with an extension, compared to women without one, had a longer median operative time (49 min versus 32 min, P<0.001) and higher rates of postpartum hemorrhage and blood transfusion (respectively, 30.1% versus 15.1%, p = 0.002 and 7.2% versus 2.4%, P = 0.03).

Conclusion

The risk of a hysterotomy extension does not appear to be associated with second-stage obstetric characteristics, including the duration of the passive phase of this stage. In our center, which practices delayed pushing, prolonging this passive phase beyond 2 hours does not increase the risk of hysterotomy extension in second-stage cesareans.