Vaginal Birth After Cesarean and Uterine Rupture Rates in California:

Prediction of Delivery Complications by First-Trimester Ultrasound Measurement of the Gestational Sac's Distance From a Previous Cesarean Section Scar

OBJECTIVES

This study was designed to investigate the clinical relationship between labor complications in the second and third trimesters and the distance from the gestational sac to a previous cesarean section (CS) scar.

METHODS

We conducted a retrospective review of the electronic medical records and included all 7- to 9-week transvaginal ultrasound examination reports from pregnancies with a history of a single cesarean delivery in our hospital between January 2015 and December 2017. Women were divided into 6 groups according to the distance of the gestational sac to the CS scar (groups A-F). A composite of pregnancy outcomes (gestational age at birth, delivery mode, placental abnormality, blood loss, uterine rupture, and hysterectomy) and other maternal and neonatal outcomes were assessed.

RESULTS

A total of 699 cases were included in our study. The median gestational age was 39.0 (range, 38.1-39.9) weeks. The median intrapartum blood loss volume was 400 (range, 300-500) mL. The results showed no statistically significant difference in blood loss (P = .297) or birth weight of the neonate (P = .318) among the distance subgroups. Overall, the fetuses were stillborn in 9 of 699 cases (1.29%). There was a statistically significant difference in a morbidly adherent placenta, placenta previa, and preterm labor, and their incidence increased with decreasing distance (P < .001; P for trend < .05). There was no statistically significant difference in uterine rupture (P = .597) or the delivery mode (P = .187) among the subgroups.

CONCLUSIONS

The relative positions of a CS scar and the gestational sac in the first trimester are associated with the incidence of placental abnormalities. As the distance decreases, the extent of a morbidly adherent placenta increases.

Trial of labor versus elective repeat cesarean delivery in twin pregnancies after a previous cesarean delivery-A systematic review and meta-analysis

OBJECTIVE

To perform a systematic review of success rates of trial of labor after cesarean (TOLAC) and maternal and neonatal outcomes in twin pregnancy versus elective repeat cesarean delivery (ERCD).

METHODS

We searched MEDLINE, EMBASE, and Web of Science from data inception to May 2018 with no language or regional restrictions, to identify all studies that compared twin TOLAC and ERCD for maternal and/or neonatal outcomes. The Newcastle-Ottawa Scale was used to assess the methodological quality of the included studies. We assessed the pooled relative risk and mean difference using a random-effects model. The pooled event rates for successful VBAC, cesarean delivery for twin B after vaginal delivery of twin A, and uterine rupture were determined.

RESULTS

Of the 841 citations identified, 10 were eligible for analysis (2336 TOLAC cases and 5763 ERCD cases). The pooled event rates for successful VBAC and uterine rupture during TOLAC were 72.2% (95% CI 59.7%-83.2%) and 0.87% (95% CI 0.51%-1.31%), respectively. TOLAC was associated with a significantly higher risk of neonatal death (RR 3.02 [95% CI 1.07-8.54]) with no significant differences in mean gestational age at birth, NICU admission rates, or 5-minute Apgar <7. Although the risk for maternal infectious morbidity was significantly lower with TOLAC (RR 0.48 [95% CI 0.25-0.90]), risks of uterine dehiscence, blood transfusions, and hysterectomy were comparable.

CONCLUSIONS

Twin TOLAC is associated with a relatively high rate of successful vaginal delivery and a low risk of uterine rupture. The finding of higher neonatal mortality rates may be influenced by prematurity, but requires further investigation.

Risk of complications in a second pregnancy following caesarean section in the first pregnancy: a population-based study

OBJECTIVE

To estimate the risks of maternal and perinatal morbidity and mortality in a second pregnancy, attributable to caesarean section in a first pregnancy.

DESIGN AND SETTING

Cross-sectional analytic study of hospital births in New South Wales, based on linked population databases.

PARTICIPANTS

136 101 women with one previous birth who gave birth to a singleton infant in NSW in 1998-2002.

MAIN OUTCOME MEASURES

Crude and adjusted odds ratios (aOR) and 95% confidence intervals (95% CI) for maternal and perinatal morbidity and mortality.

RESULTS

19% of mothers had a caesarean section in their first pregnancy. Compared with mothers who had had primary vaginal births, mothers who had had primary caesarean section and underwent labour in the second birth were at increased risk of uterine rupture (aOR, 12.3; 95% CI, 5.0-30.1; P < 0.0001), hysterectomy (3.5; 1.5-8.4; P < 0.01), postpartum haemorrhage (PPH) following vaginal delivery (1.6; 1.4-1.7; P < 0.0001), manual removal of placenta (1.3; 1.1-1.6; P < 0.01), infection (6.2; 4.7-8.2; P < 0.0001) and intensive care unit (ICU) admission (3.1; 2.1-4.7; P < 0.0001); among mothers who did not undergo labour (ie, had an elective caesarean section), there was a lower risk of PPH (0.6; 0.5-0.7; P < 0.0001) and ICU admission (0.4; 0.3-0.5; P < 0.0001). For infants there was increased risk of preterm delivery (1.2; 1.1-1.3; P < 0.0001) and neonatal intensive care unit admission following labour (1.6; 1.4-1.9; P < 0.0001) in the birth after primary caesarean section. The occurrence of stillbirth was not modified by labour.

CONCLUSIONS

Caesarean section in a first pregnancy confers additional risks on the second pregnancy, primarily associated with labour. These should be considered at the time caesarean section in the first pregnancy is being considered, particularly for elective caesarean section for non-medical reasons.

Uterine rupture during VBAC trial of labor: risk factors and fetal response

For the woman with a prior uterine scar, neither repeat elective cesarean birth nor vaginal birth after cesarean birth (VBAC) trial of labor (TOL) is risk-free. When VBAC-TOL is successful, it is associated with less morbidity than repeat cesarean birth. However, when VBAC-TOL fails due to uterine rupture, severe consequences often ensue. The challenge for clinicians today is to provide women who desire TOL after cesarean birth, a more individualized risk assessment of uterine rupture, thereby enhancing success and optimizing outcome. This article examines major risk factors for uterine rupture during VBAC-TOL. In addition, fetal response to uterine rupture and neonatal outcomes are reviewed.