Background
Guidelines for management of the second stage have been proposed since the 1800s and were created largely by expert opinion. Current retrospective data are mixed regarding differences in maternal and neonatal outcomes with a prolonged second stage. There are no randomized controlled trials that have evaluated whether extending the second stage of labor beyond current American College of Obstetricians and Gynecologists recommendations is beneficial.
Objective
The purpose of this study was to evaluate whether extending the length of labor in nulliparous women with prolonged second stage affects the incidence of cesarean delivery and maternal and neonatal outcomes.
Study Design
We conducted a randomized controlled trial of nulliparous women with singleton gestations at 36 0/7 to 41 6/7 weeks gestation who reached the American College of Obstetricians and Gynecologists definition of prolonged second stage of labor , which is 3 hours with epidural anesthesia or 2 hours without epidural anesthesia. Women were assigned randomly to extended labor for at least 1 additional hour, or to usual labor , which was defined as expedited delivery via cesarean or operative vaginal delivery. The exclusion criteria were intrauterine fetal death, planned cesarean delivery, age <18 years, and suspected major fetal anomaly. Primary outcome was incidence of cesarean delivery. Maternal and neonatal outcomes were compared secondarily. Statistical analysis was done by intention-to-treat.
Results
Seventy-eight nulliparous women were assigned randomly . All of the women had epidural anesthesia. Maternal demographics were not significantly different. The incidence of cesarean delivery was 19.5% (n = 8/41 deliveries) in the extended labor group and 43.2% (n = 16/37 deliveries) in the usual labor group (relative risk, 0.45; 95% confidence interval, 0.22–0.93). The number needed-to-treat to prevent 1 cesarean delivery was 4.2. There were no statistically significant differences in maternal or neonatal morbidity outcomes.
Conclusion
Extending the length of labor in nulliparous women with singleton gestations, epidural anesthesia, and prolonged second stage decreased the incidence of cesarean delivery by slightly more than one-half, compared with usual guidelines. Maternal or neonatal morbidity were not statistically different between the groups; however, our study was underpowered to detect small, but potentially clinical important, differences.
Guidelines for the management of the second stage of labor have been proposed since the 1800s and were created largely by expert opinion. The first large retrospective data collection was done by Hellman and Prystowsky in 1952, which showed that women who had a second stage of labor within 2 hours had a decreased rate of postpartum hemorrhage, fever, and neonatal death. Friedman, in 1955, evaluated the natural course of labor and noted that most nulliparous women without epidural anesthesia delivered within 2 hours. Recent data have suggested that obstetricians may want to extend the time limit to 3 hours to achieve a vaginal delivery for nulliparous women without an epidural and to 4 hours in those with an epidural. However, current retrospective data are mixed regarding differences in maternal and neonatal outcomes with a prolonged second stage. There are no randomized controlled trials that have evaluated whether extending the second stage of labor beyond current American College of Obstetricians and Gynecologists (ACOG) recommendations is beneficial.
The aim of this study was to evaluate whether extending the time limit of second stage of labor beyond current ACOG guidelines would affect the incidence of cesarean delivery (CD). Maternal and perinatal outcomes were also assessed.
Materials and Methods
This study was conducted from March 2014 until July 2015 at Thomas Jefferson University Hospital. The protocol was approved by the institutional review board, and all women provided written informed consent before assignment. Eligible nulliparous women were at least 18 years old with singleton pregnancies of at least 36 weeks gestation, cephalic presentation, and category I or II fetal heart tracings. Exclusion criteria included category III fetal heart tracing, previous vaginal delivery at ≥24 weeks gestation, multiple pregnancy, intrauterine fetal death, trial of labor after CD, planned CD, or suspected major fetal anomaly. Women were consented well before the second stage started, either in the office during prenatal care or early on admission to labor and delivery. Participating women did not receive compensation.
This study was a randomized controlled trial. Randomization was completed by a computer-generated list that used random block sizes of 8, 10, and 12. Group assignments were made based on sequentially numbered opaque sealed envelopes. The sequence was generated by the primary investigator (A.C.G.). Participants were consented by labor and delivery providers in the office or on admission. Women were assigned randomly to either “extended care” or “usual care” groups. Randomization was stratified by epidural status. Suggested treatment for women who were assigned randomly to the extended care group was continuing the second stage for at least 1 additional hour after reaching the ACOG prolonged second stage criteria (ie, after 3 hours in the second stage of labor with an epidural or 2 hours without an epidural). Suggested treatment for women who were assigned randomly to the usual care group was delivery soon after reaching the criteria for prolonged second stage listed by ACOG. Women were assigned randomly by labor and delivery staff at either the 3-hour mark (with epidural) or 2-hour mark (without epidural).
Except for the suggested management regarding length of the second stage as per randomization, the second stage of labor was managed according to the individual provider on labor and delivery. All patients were treated by house staff under the supervision of an attending physician. In general, on the finding of complete dilation, women without an urge to push were offered delayed pushing (ie, waiting about 1 hour before starting to push). Once pushing started, this usually was done via Valsalva maneuver. Delayed pushing was included in the total time of second stage. After reaching ACOG criteria for prolonged second stage, women in the extended care group were given at least 1 additional hour to have a spontaneous vaginal delivery (SVD) then delivered by the labor and delivery team with the option of CD, forceps-assisted vaginal delivery (FAVD), or vacuum-assisted vaginal delivery (VAVD). Women in the usual care group who reached ACOG criteria for prolonged second stage were at that point expeditiously delivered by the labor and delivery team with the option of CD, FAVD, or VAVD.
Primary outcome was CD. Maternal secondary outcome measures included incidence of: vaginal delivery (SVD and operative vaginal delivery [OVD] combined), SVD, OVD, chorioamnionitis, endometritis, postpartum hemorrhage (defined as >500 mL estimated blood loss in a vaginal delivery and >1000 mL estimated blood loss in a CD), transfusion, third- and fourth-degree laceration, and cervical laceration.
Neonatal secondary outcome measures included shoulder dystocia, birthweight, neonatal intensive care unit (NICU) admission, ventilation support with the use of continuous positive airway pressure or greater, sepsis, seizure, umbilical artery cord pH <7.10, perinatal death, and NICU length of stay.
Race/ethnicity was classified by the study participants. The classifications were non-Hispanic white, non-Hispanic black, Asian, Hispanic, or other.
A priori sample size estimation was calculated with an α of .05 and β of .20. Based on observations of successful vaginal delivery at 4-hour second stage by Mentigoglu et al, and on more recent delivery rates at our institution, we estimated that the CD rate in the usual care group (ie, soon after 3 hours with an epidural or 2 hours without an epidural) would be 50%, with a reduction to 20% at 4 hours with an epidural or 3 hours without an epidural. A total sample of 78 women was estimated to provide 80% power to detect a >2-fold decrease in CD rate. A subgroup analysis was planned for women with an epidural vs women without an epidural. Potential confounders were planned to be analyzed to determine confounding vs interaction.
The data analysis for this study was generated with SPSS software (version 20; IBM, Armonk, NY). Statistical analysis was performed by the intention-to-treat principle. Categorical variables were compared with the use of χ 2 test or Fisher exact test. Continuous variables were compared with the use of 2-tailed Student t test or Wilcoxon Rank-Sum test. A probability value of <.05 was considered statistically significant. Data were analyzed by the primary investigator (A.C.G.) with assistance from the Thomas Jefferson University Biostatistics Department.
The Consolidated Standards of Reporting Trials guidelines were followed. This trial was registered on clinicaltrials.gov ( NCT02101515 ). This study was not funded.
Results
From March 2013 through July 2015, we enrolled 78 nulliparous women, of whom 41 women were assigned to receive extended labor and 37 women were assigned to usual labor. No women were excluded or lost to follow up. All had epidural anesthesia. All women initially received the allocated intervention; however, there was a 14.1% crossover rate (extended labor, 2; usual labor, 9). Reasons for crossover in the extended labor group were maternal request (n = 1) and nonreassuring fetal heart tracing (n = 1). Reasons for crossover in the usual labor group included maternal request (n = 4) and delivery provider decision (n = 5). No women withdrew from the study. There was no loss to follow up. Figure 1 shows the trial flow diagram.
Overall, the women were 44.9% white and 25.6% African American. The average body mass index was 30.9 kg/m 2 ; 100% of the women had an epidural, and 48.7% of the women had labor induced. Maternal demographics were not significantly different, except for insurance type ( P = .03) and occiput posterior presentation ( P = .03; Table 1 ).
| Characteristics | Extended labor (n = 41) | Usual labor (n = 37) |
|---|---|---|
| Maternal age, y a | 27.6 ± 4.7 | 28.7 ± 5.4 |
| Epidural anesthesia, n (%) | 41 (100) | 37 (100) |
| Ethnicity (non-Hispanic), n (%) | 37 (90.2) | 36 (97.3) |
| Race, n (%) | ||
| Non-Hispanic white | 18 (43.9) | 17 (45.9) |
| Non-Hispanic black | 11 (26.8) | 9 (24.3) |
| Asian | 11 (26.8) | 11 (29.7) |
| Other | 1 (2.4) | 0 |
| Insurance type, n (%) b | ||
| Private | 21 (51.2) | 28 (75.7) |
| Public or self pay | 20 (48.8) | 9 (24.3) |
| Pregnancy complications, n (%) | ||
| Gestational diabetes mellitus | 4 (9.8) | 3 (8.1) |
| Pregestational diabetes mellitus | 0 | 1 (2.7) |
| Hypertensive disorder, n (%) | ||
| Chronic hypertension | 0 | 2 (5.4) |
| Gestational hypertension | 6 (14.6) | 2 (5.4) |
| Preeclampsia | 3 (7.3) | 3 (8.1) |
| Body mass index at delivery, kg/m 2 a | 32.1 ± 6.2 | 29.5 ± 4.8 |
| Prenatal weight gain, kg a | 15.2 ± 5.6 | 14.1 ± 6.2 |
| Gestational age at delivery, wk a | 40.4 ± 0.9 | 40.0 ± 1.3 |
| Induction of labor, n (%) | 22 (53.7) | 16 (43.2) |
| Cervical ripening, n (%) | 11 (26.8) | 8 (21.6) |
| Dilation on admission, cm a | 3.0 ± 1.8 | 3.8 ± 1.7 |
| Oxytocin use, n (%) | 34 (82.9) | 30 (81.1) |
| Artificial rupture of membranes, n (%) | 28 (68.3) | 17 (45.9) |
| Contraction frequency in 2nd stage, min a | 2.9 ± 1.0 | 3.3 ± 1.4 |
| Supine position in 2nd stage, n (%) | 38 (92.7) | 36 (97.3) |
| Delayed pushing, n (%) | 34 (82.9) | 30 (81.1) |
| Patient willing to do operative vaginal delivery, n (%) | 36 (87.8) | 27 (73.0) |
| Fetal position, n (%) c | ||
| Occiput anterior d | 34 (82.9) | 20 (54.1) |
| Occiput posterior e | 7 (17.1) | 15 (40.5) |
| Occiput transverse | 0 | 2 (5.4) |
| Male fetus, n (%) | 28 (68.3) | 19 (51.4) |
a Data are given as mean ± standard deviation
c Across all 3 fetal positions, P = .015
Incidence of CD was 19.5% in the extended labor group and 43.2% in the usual labor group (relative risk [RR], 0.45; 95% confidence interval [CI], 0.22–0.93; Table 2 , Figure 2 ). The number needed to treat to prevent 1 CD was 4.2. SVD was significantly increased in the extended labor group (RR, 2.71; 95% confidence interval [CI], 1.30–5.62); OVD was not significantly different between groups (RR, 0.77; 95% CI, 0.41–1.45). When we analyzed FAVD (n = 5 in extended labor group and n = 3 in usual labor group) and VAVD (n = 7 in extended labor group and n = 11 in usual labor group) separately, there was also no difference between groups (FAVD: RR, 1.50; 95% CI, 0.39–5.86; VAVD: RR, 0.57; 95% CL, 0.25–1.32). Results were similar when adjusted for confounders.
| Outcome | Extended labor (n = 41), n (%) | Usual labor (n = 37), n (%) | Relative risk | 95% Confidence interval |
|---|---|---|---|---|
| Cesarean delivery | 8 (19.5) | 16 (43.2) | 0.45 | 0.22–0.93 a |
| Vaginal delivery | 33 (80.5) | 21 (56.8) | 1.42 | 1.03–1.95 a |
| Spontaneous vaginal delivery | 21 (51.2) | 7 (18.9) | 2.71 | 1.30–5.62 a |
| Operative vaginal delivery | 12 (29.3) | 14 (37.8) | 0.77 | 0.41–1.45 a |
| Chorioamnionitis | 11 (26.8) | 13 (35.1) | 0.76 | 0.39–1.49 a |
| Endometritis | 1 (2.4) | 1 (2.7) | 0.90 | 0.06–13.92 b |
| Postpartum hemorrhage | 8 (19.5) | 3 (8.1) | 2.41 | 0.67–8.40 b |
| Transfusion | 1 (2.4) | 0 | Not estimable | Not estimable |
| Third-/fourth-degree perineal laceration | 6 (14.6) | 1 (2.7) | 5.41 | 0.68–42.90 b |
| Cervical laceration | 0 | 0 | — | — |
Stay updated, free articles. Join our Telegram channel
Full access? Get Clinical Tree
