Fetal Tachycardia in the Setting of Maternal Intrapartum Fever and Perinatal Morbidity.

OBJECTIVE: The fetal consequences of intrapartum fetal tachycardia with maternal fever or clinical chorioamnionitis are not well studied. We evaluated the association between perinatal morbidity and fetal tachycardia in the setting of intrapartum fever. STUDY DESIGN: Secondary analysis of a multicenter randomized control trial that enrolled 5,341 healthy laboring nulliparous women ≥36 weeks' gestation. Women with intrapartum fever ≥ 38.0°C (including those meeting criteria for clinical chorioamnionitis) after randomization were included in this analysis. Isolated fetal tachycardia was defined as fetal heart rate (FHR) ≥160 beats per minute for at least 10 minutes in the absence of other FHR abnormalities. FHR abnormalities other than tachycardia were excluded from the analysis. The primary outcome was a perinatal composite (5-minute Apgar's score ≤3, intubation, chest compressions, or mortality). Secondary outcomes included low arterial cord pH (pH < 7.20), base deficit ≥12, and cesarean delivery. RESULTS: A total of 986 (18.5%) of women in the trial developed intrapartum fever, and 728 (13.7%) met criteria to be analyzed; of these, 728 women 336 (46.2%) had maternal-fetal medicine (MFM) reviewer-defined fetal tachycardia, and 349 of the 550 (63.5%) women during the final hour of labor had validated software (PeriCALM) defined fetal tachycardia. After adjusting for confounders, isolated fetal tachycardia was not associated with a significant difference in the composite perinatal outcome (adjusted odds ratio [aOR] = 3.15 [0.82-12.03]) compared with absence of tachycardia. Fetal tachycardia was associated with higher odds of arterial cord pH <7.2, aOR = 1.48 (1.01-2.17) and of infants with a base deficit ≥ 12, aOR = 2.42 (1.02-5.77), but no significant difference in the odds of cesarean delivery, aOR = 1.33 (0.97-1.82). CONCLUSION: Fetal tachycardia in the setting of intrapartum fever or chorioamnionitis is associated with significantly increased fetal acidemia defined as a pH <7.2 and base excess ≥12 but not with a composite perinatal morbidity. KEY POINTS: · The perinatal outcomes associated with fetal tachycardia in the setting of maternal fever are undefined.. · Fetal tachycardia was not significantly associated with perinatal morbidity although the sample size was limited.. · Fetal tachycardia was associated with an arterial cord pH <7.2 and base deficit of 12 or greater..

Impact of metabolic acidemia at birth on neonatal outcomes in infants born before 34 weeks' gestation.

PURPOSE: To examine prematurity-associated neonatal outcomes in early preterm infants with metabolic acidemia compared to those without such acidemia. METHODS: We performed a retrospective cohort analysis to assess the impact of metabolic acidemia on prematurity-associated complications in a large cohort of singleton live-born infants with complete umbilical cord gas analyses delivered between 24 0/7 and 33 6/7 weeks. Metabolic acidemia was defined as an umbilical artery pH less than 7.0 plus a base deficit of 12 mmol/L or greater. Outcomes were adjusted for gestational age using logistic regression. RESULTS: Between 1 January 1988 and 31 December 2014, 6970 singleton early preterm infants were delivered at our hospital, of which 126 (1.8%) had metabolic acidemia. Neonatal mortality as well as prematurity-associated morbidities were significantly increased in the presence of metabolic acidemia. Included were ventilator requirement (73% versus 36%, p < 0.001), grade 3/4 intraventricular hemorrhage (10% versus 4%, p < 0.001), periventricular leukomalacia (5% versus 2%, p = 0.036), and neonatal death (13% versus 4%, p < 0.001). These significant findings persisted after adjustment for gestational age. CONCLUSION: Metabolic acidemia significantly increases the risks related to prematurity in infants delivered prior to 34 weeks' gestation.

What we have learned about intrapartum fetal monitoring trials in the MFMU Network.

The vast majority of pregnant women are subjected to electronic fetal heart monitoring during labor. There is limited evidence to support its benefit compared with intermittent auscultation. In addition, there is significant variability in interpretation and its false-positive rate is high. The latter may have contributed to the rise in operative deliveries. In order to address the critical need for better approaches to intrapartum monitoring, the MFMU Network has completed two large multisite randomized trials, one to evaluate fetal pulse oximetry and the other to evaluate fetal ECG ST segment analysis (STAN). Both of these technologies had been approved for clinical use in the United States based on prior smaller trials. These technologies were evaluated in laboring women near term and their primary outcomes were overall cesarean delivery for the oximetry trial and a composite adverse neonatal outcome for STAN. Both the trials failed to show a benefit of the technology, neither in the rates of operative deliveries nor in the rates of adverse neonatal outcomes. The experience with these trials, summarized in this report, highlights the need for rigorous evidence before introduction of new technology into clinical practice and provides a blueprint for future trials to address the need for better intrapartum monitoring approaches.

Association of Cervical Effacement With the Rate of Cervical Change in Labor Among Nulliparous Women.

OBJECTIVE: To assess the association of cervical effacement with the rate of intrapartum cervical change among nulliparous women. METHODS: We conducted a secondary analysis of a prospective trial of intrapartum fetal pulse oximetry. For women who had vaginal deliveries, interval-censored regression was used to estimate the time to dilate at 1-cm intervals. For each given centimeter of progressive cervical dilation, women were divided into those who had achieved 100% cervical effacement and those who had not. The analysis was performed separately for women in spontaneous labor and those who were given oxytocin. RESULTS: A total of 3,902 women were included in this analysis, 1,466 (38%) who underwent labor induction, 1,948 (50%) who underwent labor augmentation (combined for the analysis), and 488 (13%) who labored spontaneously. For women in spontaneous labor, the time to dilate 1 cm was shorter for those who were 100% effaced starting at 4 cm of cervical dilation (P=.01 to <.001). For women who received oxytocin, the time to dilate 1 cm was shorter for those who were 100% effaced throughout labor (P<.001). CONCLUSION: The rate of cervical dilation among nulliparous women is associated with not only the degree of cervical dilation, but also with cervical effacement. CLINICAL TRIAL REGISTRATION: ClinicalTrials.gov, www.clinicaltrials.gov, NCT00098709.

Metabolic Acidemia in Live Births at 35 Weeks of Gestation or Greater.

OBJECTIVE: To estimate the incidence of metabolic acidemia and assess its association with a variety of obstetric complications in a large cohort of singleton live births at 35 weeks of gestation or greater. METHODS: We analyzed obstetric complications and neonatal outcomes associated with metabolic acidemia in singleton newborns delivered at 35 weeks of gestation or greater. Metabolic acidemia was identified as an umbilical artery pH of less than 7.0 and a base deficit of 12 mmol/L or greater from umbilical cord blood gas analyses performed immediately after delivery. The primary outcome of interest was seizures in the immediate newborn period. RESULTS: Between January 1, 1988, and December 31, 2013, a total of 1,265 (3.9/1,000, 95% confidence interval [CI] 3.7-4.1) neonates were identified with metabolic acidemia among 323,027 live births with cord gas analysis. Virtually every recorded obstetric complication was significantly associated with metabolic acidemia. All measures of neonatal morbidity except necrotizing enterocolitis were also significantly increased in the presence of metabolic acidemia. Seizures occurred in 367 of 323,027 (1.1/1,000, 95% CI 1.0-1.3) neonates. Only 19.1% (95% CI 15.2-23.5%) occurred in those with metabolic acidemia. Among the 1,265 with metabolic acidemia, 70 were diagnosed with neonatal seizures, for a prevalence of 5.5% (95% CI 4.3-6.9) in the acidotic group. CONCLUSION: Neonatal acidemia at birth is rare in deliveries occurring at or after 35 weeks of gestation. Seizures occur in less than one in 10 newborns with metabolic acidemia. Approximately 80% of seizures in neonates at this gestational age occur in nonacidemic neonates. LEVEL OF EVIDENCE: III.

Population versus customized fetal growth norms and adverse outcomes in an intrapartum cohort.

OBJECTIVE: To compare population versus customized fetal growth norms in identifying neonates at risk for adverse outcomes (APO) associated with small for gestational age (SGA). STUDY DESIGN: Secondary analysis of an intrapartum fetal pulse oximetry trial in nulliparous women at term. Birth weight percentiles were calculated using ethnicity- and gender-specific population norms and customized norms (Gardosi). RESULTS: Of the studied neonates, 508 (9.9%) and 584 (11.3%) were SGA by population (SGApop) and customized (SGAcust) norms, respectively. SGApop infants were significantly associated with a composite adverse neonatal outcome, neonatal intensive care admission, low fetal oxygen saturation, and reduced risk of cesarean delivery; both SGApop and SGAcust infants were associated with a 5-minute Apgar score < 4. The ability of customized and population birth weight percentiles in predicting APO was poor (12 of 14 APOs had area under the curve of <0.6). CONCLUSION: In this intrapartum cohort, neither customized nor normalized population norms adequately identified neonates at risk of APO related to SGA.

Relationship between fetal station and successful vaginal delivery in nulliparous women.

OBJECTIVE: To study the relationship between fetal station and successful vaginal delivery in nulliparous women. STUDY DESIGN: This was a secondary analysis from a previously reported trial of pulse oximetry. Vaginal delivery rates were evaluated and compared with respect to the fetal station. Spontaneous labor and induction of labor groups were evaluated separately. Multivariable logistic regression analysis was performed to adjust for confounding factors. RESULTS: Successful vaginal delivery was more frequent with an engaged vertex for spontaneous labor (86.2% versus 78.6%; p = 0.01) and induced labor (87.7% versus 66.1%; p < 0.01). After adjustment, engaged fetal vertex was not associated with vaginal delivery for spontaneous labor (odds ratio [OR] 1.5; 95% confidence interval [CI] 0.95 to 2.3; p = 0.08) or for women with induced labor (OR 2.2; 95% CI 0.96 to 5.1; p = 0.06). CONCLUSION: Among nulliparous women enrolled in the FOX randomized trial in spontaneous labor or for labor induction, an engaged fetal vertex does not affect their vaginal delivery rate.

Timing of delivery and pregnancy outcomes among laboring nulliparous women.

OBJECTIVE: The objective of the study was to compare pregnancy outcomes by completed week of gestation after 39 weeks with outcomes at 39 weeks. STUDY DESIGN: Secondary analysis of a multicenter trial of fetal pulse oximetry in spontaneously laboring or induced nulliparous women at a gestation of 36 weeks or longer. Maternal outcomes included a composite (treated uterine atony, blood transfusion, and peripartum infections) and cesarean delivery. Neonatal outcomes included a composite of death, neonatal respiratory and other morbidities, and neonatal intensive care unit admission. RESULTS: Among the 4086 women studied, the risks of the composite maternal outcome (P value for trend < .001), cesarean delivery (P < .001), and composite neonatal outcome (P = .047) increased with increasing gestational age from 39 to 41 or more completed weeks. Adjusted odds ratios (95% confidence interval) for 40 and 41 or more weeks, respectively, compared with 39 weeks were 1.29 (1.03-1.64) and 2.05 (1.60-2.64) for composite maternal outcome, 1.28 (1.05-1.57) and 1.75 (1.41-2.16) for cesarean delivery, and 1.25 (0.86-1.83) and 1.37 (0.90-2.09) for composite neonatal outcome. CONCLUSION: Risks of maternal morbidity and cesarean delivery but not neonatal morbidity increased significantly beyond 39 weeks.

The diagnosis and natural history of false preterm labor.

OBJECTIVE: To estimate the natural history of pregnancies in women who present with preterm labor symptoms and who are sent home with a diagnosis of false labor. METHODS: A prospective observational study of women with singletons and intact membranes who presented to triage between 24 0/7 and 33 6/7 weeks of gestation with preterm labor symptoms and cervical dilation less than 2 cm was conducted. Women sent home with a diagnosis of false preterm labor were analyzed against a comparable general obstetric population delivered during the same time period. The primary outcome was delivery before 37 weeks of gestation. Secondary outcomes included the interval between presentation and delivery, as well as maternal and neonatal outcomes. RESULTS: Of the 843 women who met inclusion criteria, 690 (82%) were sent home with a diagnosis of false preterm labor and 153 (18%) were admitted to labor and delivery. When analyzed compared with a comparable general obstetric population, women sent home had a similar rate of birth before 34 weeks of gestation (2% compared with 1%, P=.28) but a higher rate of birth between 34 and 36 weeks of gestation (5% compared with 2%, P<.001). There was no difference in neonatal mortality (0% compared with 0.3%, P=.18). Women with cervical dilation of 1 cm at discharge were more likely to deliver before 34 weeks of gestation compared with nondilated women (5% compared with 1%, P=.02); however, 89% of the 1-cm group delivered more than 21 days after presentation. CONCLUSION: Women sent home with a diagnosis of false preterm labor are not at increased risk for early preterm birth or neonatal mortality; however, they are at increased risk for late preterm birth. LEVEL OF EVIDENCE: II.

Increasing maternal body mass index and characteristics of the second stage of labor.

OBJECTIVE: To evaluate the length of the second stage of labor in relation to increasing maternal prepregnancy body mass index (BMI) among nulliparous parturient women, and to determine whether route of delivery differs among obese, overweight, and normal-weight women reaching the second stage of labor. METHODS: We performed a secondary analysis of a multicenter trial of fetal pulse oximetry conducted among 5,341 nulliparous women who were induced or labored spontaneously at 36 weeks or more of gestation. Normal weight was defined as BMI of 18.5-24.9 kg/m, overweight was a BMI of 25.0-29.9 kg/m, and obese was a BMI of 30 or higher. RESULTS: Of the 5,341 women, 97% had prepregnancy BMI recorded. Of these, 3,739 had BMIs of 18.5 or higher and reached the second stage of labor. Increasing maternal BMI was not associated with second stage duration: normal weight, 1.1 hour; overweight, 1.1 hour; and obese, 1.0 hours (P=.13). Among women who reached the second stage, as BMI increased, so did the likelihood that the woman had undergone induction of labor. Even so, the lack of association between second-stage duration and BMI did not vary by method of labor onset (P=.84). The rate of cesarean delivery in the second stage did not differ by increasing BMI (normal weight 7.1%, overweight 9.6%, obese 6.9%, P=.17). CONCLUSION: Among nulliparous women who reach the second stage of labor, increasing maternal BMI is not associated with a longer second stage or an increased risk of cesarean delivery. LEVEL OF EVIDENCE: II.

Urodynamic indices and pelvic organ prolapse quantification 3 months after vaginal delivery in primiparous women.

INTRODUCTION AND HYPOTHESIS: This study aims to describe multichannel urodynamic indices and pelvic organ prolapse quantification (POP-Q) in primiparous women 3 months after vaginal delivery. METHODS: This was a secondary analysis of a group of women who had been randomized to either coached or non-coached pushing during the second stage of labor. Primiparous women were evaluated with POP-Q examination and multichannel urodynamic testing 3 months after vaginal delivery. RESULTS: Of 128 women evaluated, the cumulative stage of prolapse was distributed as 4.7% stage 0, 39% stage I, 56% stage II, and none with stage III prolapse or greater. For the anterior compartment, most had stage II prolapse. Stage I prolapse predominated for both the central and posterior compartments. Of the women, 14.1% had urodynamic stress incontinence, 12.5% had detrusor overactivity, and 6% had both. CONCLUSIONS: In a predominantly Hispanic primiparous population, ICS POP-Q stage II prolapse of the vagina, urodynamic stress incontinence, and detrusor overactivity are common findings at a 3-month postpartum assessment.

Failed labor induction: toward an objective diagnosis.

OBJECTIVE: To evaluate maternal and perinatal outcomes in women undergoing labor induction with an unfavorable cervix according to duration of oxytocin administration in the latent phase of labor after ruptured membranes. METHODS: This was a secondary analysis of a randomized multicenter trial in which all cervical examinations from admission were recorded. INCLUSION CRITERIA: nulliparas at or beyond 36 weeks of gestation undergoing induction with a cervix of 2 cm or less dilated and less than completely effaced. The latent phase of labor was defined as ending at a cervical dilation of 4 cm and effacement of at least 90%, or at a cervical dilation of 5 cm regardless of effacement. RESULTS: A total of 1,347 women were analyzed. The overall vaginal delivery rate was 63.2%. Most women had exited the latent phase after 6 hours of oxytocin and membrane rupture (n=939; 69.7%); only 5% remained in the latent phase after 12 hours. The longer the latent phase, the lower the vaginal delivery rate. Even so, 39.4% of the 71 women who remained in the latent phase after 12 hours of oxytocin and membrane rupture were delivered vaginally. Chorioamnionitis, endometritis, or both, and uterine atony were the only maternal adverse outcomes related to latent-phase duration: adjusted odds ratios (95% confidence intervals) of 1.12 (1.07, 1.17) and 1.13 (1.06, 1.19), respectively, for each additional hour. Neonatal outcomes were not related to latent-phase duration. CONCLUSION: Almost 40% of the women who remained in the latent phase after 12 hours of oxytocin and membrane rupture were delivered vaginally. Therefore, it is reasonable to avoid deeming labor induction a failure in the latent phase until oxytocin has been administered for at least 12 hours after membrane rupture. LEVEL OF EVIDENCE: III.

Neonatal outcomes and operative vaginal delivery versus cesarean delivery.

We compared outcomes for neonates with forceps-assisted, vacuum-assisted, or cesarean delivery in the second stage of labor. This is a secondary analysis of a randomized trial in laboring, low-risk, nulliparous women at >or=36 weeks' gestation. Neonatal outcomes after use of forceps, vacuum, and cesarean were compared among women in the second stage of labor at station +1 or below (thirds scale) for failure of descent or nonreassuring fetal status. Nine hundred ninety women were included in this analysis: 549 (55%) with an indication for delivery of failure of descent and 441 (45%) for a nonreassuring fetal status. Umbilical cord gases were available for 87% of neonates. We found no differences in the base excess (P = 0.35 and 0.78 for failure of descent and nonreassuring fetal status) or frequencies of pH below 7.0 (P = 0.73 and 0.34 for failure of descent and nonreassuring fetal status) among the three delivery methods. Birth outcomes and umbilical cord blood gas values were similar for those neonates with a forceps-assisted, vacuum-assisted, or cesarean delivery in the second stage of labor. The occurrence of significant fetal acidemia was not different among the three delivery methods regardless of the indication.

Second-stage labor duration in nulliparous women: relationship to maternal and perinatal outcomes.

OBJECTIVE: The purpose of this study was to assess maternal and perinatal outcomes as a function of second-stage labor duration. STUDY DESIGN: We assessed outcomes in nulliparous laboring women who were enrolled in a trial of fetal pulse oximetry. RESULTS: Of 5341 participants, 4126 women reached the second stage of labor. As the duration of the second stage increased, spontaneous vaginal delivery rates declined, from 85% when the duration was <1 hour to 9% when it was > or =5 hours. Adverse maternal outcomes that were associated significantly with the duration of the second stage of labor included chorioamnionitis (overall rate, 3.9%), third- or fourth-degree perineal laceration (overall rate, 8.7%), and uterine atony (overall rate, 3.9%). Odds ratios for each additional hour of the second stage of labor ranged from 1.3-1.8. Among individual adverse neonatal outcomes, only admission to a neonatal intensive care unit was associated significantly with second stage duration (odds ratio, 1.4). CONCLUSION: The second stage of labor does not need to be terminated for duration alone.

Decreased preterm births in an inner-city public hospital.

OBJECTIVE: To examine preterm births among African-American and Hispanic women who delivered at an inner-city public hospital in the context of contemporaneously increasing rates in the United States. METHODS: The rates of preterm birth, defined as birth before 37 weeks of gestation, for singleton neonates with birth weights of 500 g or higher delivered to women who had prenatal care at Parkland Hospital between 1988 and 2006 were compared with similar births in the United States from 1995 to 2002. Preterm birth rates also were compared for white, African-American, and Hispanic women as were disparity in these rates using white women as the referent. RESULTS: The Parkland Memorial Hospital cohort included 260,197 women, of whom 70% were Hispanic, 20% African-American, and 8% white. The U.S. cohort included 29,366,816 women, of whom 61% were white, 19% Hispanic, and 14% African-American. Between 1995 and 2002, the rate of preterm birth in the United States increased from 9.4% to 10.1% (P<.001). Between 1988 and 2006, the rate of preterm births at Parkland decreased from 10.4% to 4.9% (P<.001). Moreover, the rates of preterm birth were significantly lower in Hispanic and African-American women who delivered at Parkland compared with the same ethnicity/race groups in the U.S. cohort. The decline in preterm births at Parkland Memorial Hospital coincided with increased prenatal care use. CONCLUSION: Preterm birth significantly decreased in minority women delivered at an inner-city public hospital. We hypothesize that the reduction in preterm births was the result of a public health care program specifically targeting minority pregnant women.

Fetal pulse oximetry and cesarean delivery.

BACKGROUND: Knowledge of fetal oxygen saturation, as an adjunct to electronic fetal monitoring, may be associated with a significant change in the rate of cesarean deliveries or the infant's condition at birth. METHODS: We randomly assigned 5341 nulliparous women who were at term and in early labor to either "open" or "masked" fetal pulse oximetry. In the open group, fetal oxygen saturation values were displayed to the clinician. In the masked group, the fetal oxygen sensor was inserted and the values were recorded by computer, but the data were hidden. Labor complicated by a nonreassuring fetal heart rate before randomization was documented for subsequent analysis. RESULTS: There was no significant difference in the overall rates of cesarean delivery between the open and masked groups (26.3% and 27.5%, respectively; P=0.31). The rates of cesarean delivery associated with the separate indications of a nonreassuring fetal heart rate (7.1% and 7.9%, respectively; P=0.30) and dystocia (18.6% and 19.2%, respectively; P=0.59) were similar between the two groups. Similar findings were observed in the subgroup of 2168 women in whom a nonreassuring fetal heart rate was detected before randomization. The condition of the infants at birth did not differ significantly between the two groups. CONCLUSIONS: Knowledge of the fetal oxygen saturation is not associated with a reduction in the rate of cesarean delivery or with improvement in the condition of the newborn. (ClinicalTrials.gov number, NCT00098709 [ClinicalTrials.gov].).

Decision-to-incision times and maternal and infant outcomes.

OBJECTIVE: To measure decision-to-incision intervals and related maternal and neonatal outcomes in a cohort of women undergoing emergency cesarean deliveries at multiple university-based hospitals comprising the National Institute of Child Health and Human Development Maternal-Fetal Medicine Units Network. METHODS: All women undergoing a primary cesarean delivery at a Network center during a 2-year time span were prospectively ascertained. Emergency procedures were defined as those performed for umbilical cord prolapse, placental abruption, placenta previa with hemorrhage, nonreassuring fetal heart rate pattern, or uterine rupture. Detailed information regarding maternal and neonatal outcomes, including the interval from the decision time to perform cesarean delivery to the actual skin incision, was collected. RESULTS: Of the 11,481 primary cesarean deliveries, 2,808 were performed for an emergency indication. Of these, 1,814 (65%) began within 30 minutes of the decision to operate. Maternal complication rates, including endometritis, wound infection, and operative injury, were not related to the decision-to-incision interval. Measures of newborn compromise including umbilical artery pH less than 7 and intubation in the delivery room were significantly greater when the cesarean delivery was commenced within 30 minutes, likely attesting to the need for expedited delivery. Of the infants with indications for an emergency cesarean delivery who were delivered more than 30 minutes after the decision to operate, 95% did not experience a measure of newborn compromise. CONCLUSION: Approximately one third of primary cesarean deliveries performed for emergency indications are commenced more than 30 minutes after the decision to operate, and the majority were for nonreassuring heart rate tracings. In these cases, adverse neonatal outcomes were not increased. LEVEL OF EVIDENCE: II-2.

Risk of uterine rupture with a trial of labor in women with multiple and single prior cesarean delivery.

OBJECTIVE: To determine whether the risk for uterine rupture is increased in women attempting vaginal birth after multiple cesarean deliveries. METHODS: We conducted a prospective multicenter observational study of women with prior cesarean delivery undergoing trial of labor and elective repeat operation. Maternal and perinatal outcomes were compared among women attempting vaginal birth after multiple cesarean deliveries and those with a single prior cesarean delivery. We also compared outcomes for women with multiple prior cesarean deliveries undergoing trial of labor with those electing repeat cesarean delivery. RESULTS: Uterine rupture occurred in 9 of 975 (0.9%) women with multiple prior cesarean compared with 115 of 16,915 (0.7%) women with a single prior operation (P = .37). Multivariable analysis confirmed that multiple prior cesarean delivery was not associated with an increased risk for uterine rupture. The rates of hysterectomy (0.6% versus 0.2%, P = .023) and transfusion (3.2% versus 1.6%, P < .001) were increased in women with multiple prior cesarean deliveries compared with women with a single prior cesarean delivery attempting trial of labor. Similarly, a composite of maternal morbidity was increased in women with multiple prior cesarean deliveries undergoing trial of labor compared with those having elective repeat cesarean delivery (odds ratio 1.41, 95% confidence interval 1.02-1.93). CONCLUSION: A history of multiple cesarean deliveries is not associated with an increased rate of uterine rupture in women attempting vaginal birth compared with those with a single prior operation. Maternal morbidity is increased with trial of labor after multiple cesarean deliveries, compared with elective repeat cesarean delivery, but the absolute risk for complications is small. Vaginal birth after multiple cesarean deliveries should remain an option for eligible women. LEVEL OF EVIDENCE: II-2.