Oded Langer

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

Trial of labor or repeat cesarean delivery in women with morbid obesity and previous cesarean delivery

OBJECTIVEnAssess effects of body mass index (BMI) on trial of labor after previous cesarean delivery and determine whether morbidly obese women have greater maternal and perinatal morbidity with trial of labor compared with elective repeat cesarean delivery.nnnMETHODSnSecondary analysis from a prospective observational study included all term singletons undergoing trial of labor after previous cesarean delivery. Body mass index groups were as follows: normal 18.5-24.9, overweight 25.0-29.9, obese 30.0-39.9, morbidly obese 40.0 kg/m2 or greater, and were compared for failure and maternal and neonatal morbidities. The morbidly obese trial of labor and elective repeat cesarean delivery were compared for maternal and neonatal morbidities. Multivariable logistic regression analysis controlled for confounding variables.nnnRESULTSnThere were 14,142 trial of labor participants and 14,304 elective repeat cesarean delivery participants. Increasing BMI was directly associated with failed trial of labor after previous cesarean delivery: from 15.2% in normal weight (1,344) to 39.3% in morbidly obese (1,638), with combined risk of rupture/dehiscence increasing from 0.9% to 2.1% in morbidly obese women. Among morbidly obese women, trial of labor carried greater than five-fold risk of uterine rupture/dehiscence (2.1% versus 0.4%), almost a two-fold increase in composite maternal morbidity (7.2% versus 3.8%) and five-fold risk of neonatal injury (1.1% versus 0.2%) (fractures, brachial plexus injuries, and lacerations), but no neonatal encephalopathy. Morbidly obese women failing a trial of labor had six-fold greater composite maternal morbidity than those undergoing a successful trial of labor (14.2% versus 2.6%).nnnCONCLUSIONnBody mass index correlates with outcomes in trial of labor after previous cesarean delivery. Morbidly obese women undergoing a trial of labor were at increased risk for failure. Increased BMI was associated with greater composite morbidity and neonatal injury compared with elective repeat cesarean delivery, but absolute morbidities were small. Increased risks should be considered before trial of labor after previous cesarean delivery.nnnLEVEL OF EVIDENCEnII-2.Electrodeposited nanocrystalline Co offers a relatively unique opportunity to study the interaction of two fundamentally different elementary solid state reactions: grain growth and ε (HCP) to α (FCC) allotropic phase transformation. Samples were isothermally annealed at temperatures above and below the equilibrium transformation temperature (Tεαu2009=u2009695u2009K) and quenched to ambient for subsequent characterization by X-ray diffraction (XRD) and transmission electron microscopy (TEM). Isothermal annealing above 695u2009K resulted in concurrent grain growth and ε to α transformation. Unexpectedly, however, simultaneous grain growth and ε to α transformation also occurred during isothermal annealing at temperatures as low as 573u2009K, i.e. 122u2009K below the expected equilibrium Tεα. It was observed that non-equilibrium α-Co formed within a matrix of nanocrystalline ε-Co via abnormal grain growth, and is therefore fundamentally different from the ε to α transformation typically observed in conventional polycrystalline Co.

Pregnancy outcomes for women with placenta previa in relation to the number of prior cesarean deliveries

OBJECTIVE: To estimate the association between the number of prior cesarean deliveries and pregnancy outcomes among women with placenta previa. METHODS: Women with a placenta previa and a singleton gestation were identified in a concurrently collected database of cesarean deliveries performed at 19 academic centers during a 4-year period. Maternal and perinatal outcomes were analyzed after stratifying by the number of cesarean deliveries before the index pregnancy. RESULTS: Of the 868 women in the analysis, 488 had no prior cesarean delivery, 252 had one prior cesarean delivery, 76 had two prior cesarean deliveries, and 52 had at least three prior cesarean deliveries. Multiple measures of maternal morbidity (eg, coagulopathy, hysterectomy, pulmonary edema) increased in frequency as the number of prior cesarean deliveries rose. Even one prior cesarean delivery was sufficient to increase the risk of an adverse maternal outcome (a composite of transfusion, hysterectomy, operative injury, coagulopathy, venous thromboembolism, pulmonary edema, or death) from 15% to 23%, which corresponded, in multivariable analysis, to an adjusted odds ratio of 1.9 (95% confidence interval 1.2–2.9). Conversely, gestational age at delivery and adverse perinatal outcome (a composite measure of respiratory distress syndrome, necrotizing enterocolitis, intraventricular hemorrhage grade 3 or 4, seizures, or death) were unrelated to the number of prior cesarean deliveries. CONCLUSION: Among women with a placenta previa, an increasing number of prior cesarean deliveries is associated with increasing maternal, but not perinatal, morbidity. LEVEL OF EVIDENCE: II

Outcomes of induction of labor after one prior cesarean.

OBJECTIVE: To compare pregnancy outcomes in women with one prior low-transverse cesarean delivery after induction of labor with pregnancy outcomes after spontaneous labor. METHODS: This study is an analysis of women with one prior low-transverse cesarean and a singleton gestation who underwent a trial of labor and who were enrolled in a 4-year prospective observational study. Pregnancy outcomes were evaluated according to whether a woman underwent spontaneous labor or labor induction. RESULTS: Among the 11,778 women studied, vaginal delivery was less likely after induction of labor both in women without and with a prior vaginal delivery (51% versus 65%, P<.001; and 83% versus 88%, P<.001). An increased risk of uterine rupture after labor induction was found only in women with no prior vaginal delivery (1.5% versus 0.8%, P=.02; and 0.6% versus 0.4%, P=.42). Blood transfusion, venous thromboembolism, and hysterectomy were also more common with induction among women without a prior vaginal delivery. No measure of perinatal morbidity was associated with labor induction. An unfavorable cervix at labor induction was not associated with any adverse outcomes except an increased risk of cesarean delivery. CONCLUSION: Induction of labor in the study population is associated with an increased risk of cesarean delivery in all women with an unfavorable cervix, a statistically significant, albeit clinically small, increase in maternal morbidity in women with no prior vaginal delivery, and no appreciable increase in perinatal morbidity. LEVEL OF EVIDENCE: II

Labor outcomes with increasing number of prior vaginal births after cesarean delivery

OBJECTIVE: To estimate the success rates and risks of an attempted vaginal birth after cesarean delivery (VBAC) according to the number of prior successful VBACs. METHODS: From a prospective multicenter registry collected at 19 clinical centers from 1999 to 2002, we selected women with one or more prior low transverse cesarean deliveries who attempted a VBAC in the current pregnancy. Outcomes were compared according to the number of prior VBAC attempts subsequent to the last cesarean delivery. RESULTS: Among 13,532 women meeting eligibility criteria, VBAC success increased with increasing number of prior VBACs: 63.3%, 87.6%, 90.9%, 90.6%, and 91.6% for those with 0, 1, 2, 3, and 4 or more prior VBACs, respectively (P<.001). The rate of uterine rupture decreased after the first successful VBAC and did not increase thereafter: 0.87%, 0.45%, 0.38%, 0.54%, 0.52% (P=.03). The risk of uterine dehiscence and other peripartum complications also declined statistically after the first successful VBAC. No increase in neonatal morbidities was seen with increasing VBAC number thereafter. CONCLUSION: Women with prior successful VBAC attempts are at low risk for maternal and neonatal complications during subsequent VBAC attempts. An increasing number of prior VBACs is associated with a greater probability of VBAC success, as well as a lower risk of uterine rupture and perinatal complications in the current pregnancy. LEVEL OF EVIDENCE: II

Maternal and neonatal outcomes of repeat cesarean delivery in women with a prior classical versus low transverse uterine incision

We compared maternal and neonatal outcomes following repeat cesarean delivery (CD) of women with a prior classical CD with those with a prior low transverse CD. The Maternal Fetal Medicine Units Network Cesarean Delivery Registry was used to identify women with one previous CD who underwent an elective repeat CD prior to the onset of labor at ≥36 weeks. Outcomes were compared between women with a previous classical CD and those with a prior low transverse CD. Of the 7936 women who met study criteria, 122 had a prior classical CD. Women with a prior classical CD had a higher rate of classical uterine incision at repeat CD (12.73% versus 0.59%; Pu2009<u20090.001), had longer total operative time and hospital stay, and had higher intensive care unit admission. Uterine dehiscence was more frequent in women with a prior classical CD (2.46% versus 0.27%, odds ratio 9.35, 95% confidence interval 1.76 to 31.93). After adjusting for confounding factors, there were no statistical differences in major maternal or neonatal morbidities between groups. Uterine dehiscence was present at repeat CD in 2.46% of women with a prior classical CD. However, major maternal morbidities were similar to those with a prior low transverse CD.

MODE OF DELIVERY IN WOMEN WITH ANTEPARTUM FETAL DEATH AND PRIOR CESAREAN DELIVERY

We describe obstetric outcomes in a group of patients with prior cesarean delivery (CD) presenting with an intrauterine fetal demise (IUFD). A secondary analysis of an observational study of women with prior CD was performed. All antepartum singleton pregnancies with a prior CD and IUFD ≥20 weeks gestation or 500 g were evaluated. Two hundred nine patients met inclusion criteria for analysis. The mean gestational ageu2009±u2009standard deviation at delivery was 31.3u2009±u20096.5 weeks. The trial of labor rate was 75.6% (158/209), and the vaginal birth after cesarean (VBAC) success rate was 86.7%. Labor induction or augmentation occurred in 83.3% of attempted VBAC. Uterine rupture occurred in five women (2.4%), and in 3.4% of those being induced but none of these required hysterectomy. Women with a history of previous CD and an IUFD often undergo trial of labor with a high VBAC success rate. Uterine rupture complicates 2.4% of such cases.