Vaginal birth after cesarean (VBAC): fear it or dare it? An evaluation of potential risk factors

An innovative web-based decision-aid about birth after cesarean for shared decision making in Taiwan: study protocol for a randomized control trial

BACKGROUND

Taiwan has a high national caesarean rate coupled with a low vaginal birth after caesarean (VBAC) rate. This study aims to develop and evaluate a web-based decision-aid with communication support tools, to increase shared decision making (SDM) about birth after caesarean.

METHODS

A quantitative approach will be adopted using a randomized pre-test and post-test experimental design in a medical centre in northern Taiwan. The web-based decision aid consists of five sections. Section 1 provides a two-part video to introduce SDM and how to participate in SDM. Section 2 presents an overview of functions and features of the birth decision-aid. Section 3 presents relevant VBAC information, including definitions, benefits and risks, and an artificial intelligence (AI) calculator for rate and likelihood of VBAC success. Section 4 presents the information regarding elective repeat caesarean delivery (ERCD), involving definitions, benefits, and risks. Section 5 comprises four steps of decision making to meet women's values and preferences. Pregnant women who have had one previous caesarean and are eligible for VBAC, will be recruited at 14-16 weeks. Participants will complete a baseline survey prior to random allocation to either the control group (usual care) or intervention group (usual care plus an AI-decision aid). A follow up survey at 35-38 weeks will measure change in decisional conflict, knowledge, birth mode preference, and decision-aid acceptability. Actual birth outcomes and satisfaction will be assessed one month after birth.

DISCUSSION

The innovative web-based decision-aid with support tools will help to promote pregnant women's decision-making engagement and communication with their providers and improve opportunities for supportive communication about VBAC SDM in Taiwan. Linking web-based AI data analysis into the medical record will also be assessed for feasibility during implementation in clinical practice.

TRIAL REGISTRATION

ClinicalTrials.gov identifier (NCT05091944), Registered on October 24, 2021.

Intraoperative ultrasound during repeat cesarean delivery facilitates sampling of uterine scar tissue

OBJECTIVES

Histological examination of uterine scars provides insight into uterine wound healing and helps to develop prevention methods of uterine wall rupture after previous uterine surgery. Therefore, exact intraoperative scar identification is needed for specimen collection from the actual scar tissue. The aim of this study was to correlate pre- and intraoperative ultrasound measurements of the lower uterine segment (LUS) with histological findings of scar tissue and to evaluate the relevance of intraoperative ultrasound.

METHODS

In a prospective observational study, preoperative and intraoperative sonographic measurements of the LUS thickness were performed in 33 women with a history of at least one cesarean delivery. Intraoperative ultrasound with a linear transducer placed directly on the uterus identified the scar area and uterotomy was performed 2 cm cranially. Tissue samples were taken after extraction of the fetus, embedded in paraffin wax, and stained according to Gomori Trichrome to identify scar tissue. Collagen content was evaluated with imaging software Fiji (NIH, Bethesda, USA). Preoperative and intraoperative sonographic measurements were correlated with histologic evidence of scar tissue.

RESULTS

Histological evidence of scar tissue was found in 11 out of 33 samples with significantly lower ultrasonographic thickness of the lower uterine segment compared to the other 22 samples, both antepartum (1.4 mm [1.3-1.9] vs. 2.0 mm [1.6-2.6], p=0.03) and intrapartum (1.6 mm [1.3-1.9] vs. 3.7 mm [2.0-4.7], p<0.01). Intraoperative ultrasound had a significantly higher predictive power (AUC difference 0.18 [0.03-0.33], p=0.01).

CONCLUSIONS

Intraoperative sonography identifies the uterine wall area with histologically confirmable scar tissue far better than preoperative sonography.

Vaginal birth after caesarean section before and during COVID-19 pandemic. Factors associated with successful vaginal birth

Background

The ratio of caesarean has been increasing considerably in many countries. Planning a vaginal birth after a previous caesarean is considered an important option for women in a subsequent pregnancy.

Aims

To analyse obstetric and neonatal outcomes in women in labour after caesarean section before and during the COVID-19 pandemic, and to determine factors associated with successful vaginal birth after caesarean (VBAC).

Methods

Observational cohort study of women in labour with history of caesarean section who gave birth between March 2019 and December 2020 in a tertiary hospital in southern Spain. Consecutive sampling was performed using the maternal birth database and a descriptive and inferential analysis of the study variables was carried out. Socio-demographic, obstetric and neonatal variables were compared between the pre-pandemic and pandemic periods. Multiple logistic regression analysis was performed to determine variables associated with VBAC success.

Findings

The VBAC success rate was 67.4%. The caesarean section rate was significantly higher during the COVID-19 pandemic period. Factors associated with VBAC success were: birth before the pandemic (OR 0.32) and at night (OR 0.45), use of epidural analgesia (OR 2.14), and having had a previous vaginal birth (OR 1.98).

Conclusions

The success rate of VBAC was lower during the pandemic. Knowledge of the factors related to VBAC success is critical for practitioners when supporting women in decision-making about mode of birth after a previous caesarean section.