The study uses a two arm, un-blinded randomised controlled design, to compare the outcomes for women who had midwifery continuity of care compared with those who had standard maternity care.
Aim and objectives
The primary aim is to determine whether midwifery continuity of care for women with a previous CS increases the proportion of women who attempt vaginal birth in their current pregnancy. The primary hypothesis is that women with a previous CS, who are eligible for a vaginal birth and receive midwifery continuity of care, will be 50% more likely to choose to attempt a vaginal birth in their current pregnancy than similar women receiving standard care.
The secondary aims are to determine whether midwifery continuity of care increases the proportion of women experiencing a vaginal birth, and affects neonatal health or the emotional outcomes for women; and to explore the differences in women’s experiences of care and the decision making processes between the groups.
All eligible women booking maternity care at two study sites in Australia will be invited to participate.
Our study of VBAC in NSW  showed that only 35% of women who are eligible for a vaginal birth following one previous CS attempted VBAC. The trial is designed to detect a clinically significant increase in the primary outcome, attempted VBAC, from 35% to 52.5%. In order to detect this difference 274 women will be required, providing 80% power with α = 0.05. To allow for a 15% loss to follow-up, a total of 332 women will be required, 166 in each group. This sample size will also be sufficient to demonstrate a significant improvement in VBAC success rates from 53% to 70.5% (n = 262).
The data informing the sample size calculations are drawn from a published cross-sectional study using population-based data from NSW [17, 31] and descriptive data from the Obstetrix perinatal database at one of our study sites. Currently, midwives at this hospital providing continuity of care to women eligible for a VBAC are achieving attempt rates of 62.5% and success rates of 76%.
Control and intervention groups
Midwifery continuity of care (CofC)
Women allocated to the intervention group will receive midwifery continuity of care from a small group of midwives. The midwives provide care during the antenatal, labour and birth, and postnatal periods (to two weeks postnatal). Midwives will adhere to The National Midwifery Guidelines for Consultation & Referral . All women will have an appointment with an obstetric consultant during pregnancy (to re-assess VBAC suitability and discuss the birth plan). If a woman develops complications during pregnancy and requires additional care, she will continue with the midwifery continuity of care model while also attending obstetric or other consultations (this is the same for both groups). Labour and birth care will be provided at the hospital’s birth unit/labour ward and postnatal care will be provided in hospital or the woman’s own home following discharge from hospital.
Standard midwifery care
Women allocated to the control group will receive the current model of public maternity care at the two study sites. Antenatal care is provided by antenatal staff (midwives and obstetricians). Staff in the Birth Unit provides labour and birth care and midwives in the postnatal ward provide postnatal care. Women are also offered midwifery visits at home following discharge from hospital (4–48 hours after a vaginal birth). All these care providers are different people.
Most recent birth was by lower-segment CS
No more than one previous CS
Considered low risk, other than a history of one previous CS
No other previous uterine incision
No previous uterine rupture
No contraindications for vaginal birth at the time of enrolment
English proficiency (spoken and written)
No known preference for a certain model of care, such as: GP-shared care or midwifery continuity of care
Women telephone the booking office to book for maternity care and receive an appointment for their first/booking-in visit. The women will be initially screened by the booking clerk for eligibility into the trial according to the eligibility criteria. An information pack about the study is posted to all eligible women. At the first/booking-in visit, the research assistant (RA) approaches each eligible woman and asks if she received the information and whether she is interested in participating. If the woman agrees, the consent form is signed and the woman is registered as a trial participant and the remote telephone allocation service at the university is contacted for random allocation.
Randomisation will be on a 1:1 basis. Allocation concealment will be assured by using a remote telephone allocation service through the university research department. The RA will telephone the university to provide the woman’s initials, medical record number and date of birth. The clerk at the university campus will allocate women based on a randomization schedule developed independently from the RA. The midwife will be informed of the group to which the woman has been allocated and will receive her study number, which will be recorded in the Trial Register and Log Book. If allocated to standard care, the woman will be advised of her next clinic appointment. If allocated to midwifery continuity of care, she will be advised that the continuity of care midwives will contact her with a suitable appointment time.
The majority of clinical data required for the study are routinely collected and available in hospital records. The RA will collect these data and 5% of the records will be double checked by one of the CIs to verify their accuracy and consistency.
Previous pregnancy outcomes
Socio-economic status (derived from postcode, marital and employment status,)
Past medical, surgical and obstetric risk factors
Labour and birth
Artificial rupture of membranes
Immersion in water for pain relief
Epidural or spinal anaesthesia
Mode of birth
Uterine rupture or scar dehiscence
Major postpartum haemorrhage > 1000 mL and/or requiring operative procedure and/or blood transfusion
Length of hospital stay
Readmission Admission to ICU/HDU
Maternal death (within 42 days)
Apgar score < 7 at 5 min
Admissions to neonatal unit within 48 hours of birth for at least 48 hours with feeding difficulties or respiratory distress
Readmission to hospital
Breastfeeding within 1 hour of birth
Skin to skin contact within one hour of birth
Mode of feeding at 6 weeks
Stillbirth and neonatal death (within first 28 days)
Two questionnaires have been developed for administration at 36 weeks gestation (during pregnancy) and at 6–8 weeks post-partum (after the birth). These will enable women to report on their experiences with the model of care, their planned mode of birth (VBAC or CS) and the factors influencing the mode of birth choice. Distress and anxiety will be assessed using the Depression Anxiety Stress Scale (DASS 21)  and Edinburgh Postnatal Depression Scale (EDPS) . Decisional conflict, knowledge, and anxiety will be assessed using measures from a previous Australian study .
The postnatal questionnaire includes questions about their labour and birth experiences and satisfaction with their decisions. With permission, we have adapted questions about the experience of care from surveys used to assess satisfaction in the COSMOS Study which examined the impact of caseload midwifery care on low risk women in Melbourne, Australia .
Both questionnaires were piloted with pregnant and postpartum women. Completion of each took approximately 20 minutes and they were reported to be understandable to the average adult reader.
Administration of questionnaires
The questionnaires have been professionally designed and printed. The women will be posted the questionnaires with a self-addressed envelope with a reply-paid stamp. The RA will contact participants to inform them that the questionnaire has been posted. The questionnaires will be linked to the participant by attaching the study code (documented in the log book) to the inside of the front cover of each booklet.
The analysis will be by ‘intention to treat’, including withdrawals and losses to follow-up. Randomisation should ensure that the groups are similar or equivalent in their baseline characteristics; additional multivariate analysis will be used if baseline differences are noted between the two groups. The relative risks (with 95% confidence intervals) of the primary outcomes will be calculated. Secondary outcome measures of categorical data will be analysed with χ2 tests and continuous data will be analysed with t-tests (for normally distributed data). Ranked or Likert-scale data will be analysed using cumulative odds ratios. Logistic regression and multiple linear regressions will be used if necessary to adjust for any other confounding variables.
It is not possible to blind participants to the model of care they receive, but outcome assessments will be blinded.
A multidisciplinary data-monitoring group has appointed at the outset of the study to monitor the safety of the trial particularly examining differences between the groups that may be larger than expected and assessing any serious adverse effects that may occur. After 50% of the women have enrolled, a difference of at least three standard deviations in the interim analysis of a major endpoint will be needed to justify stopping the trial.
Confidentiality and data security
All paperwork, documentation, internet and audiotaped data will be treated with confidentiality. The log books required on–site are kept in the office of the booking clerk. This office is staffed during business hours, and is only used by one staff member. The door is locked when the room is empty. Hard copies of client details and study matters are kept in a filing cabinet within the locked area at the university.
Human Research Ethics Committee (HREC) approval for all current sites has been provided by the North Sydney Central Coast HREC, according to the single site HREC approval for multicentre clinical trials guidelines. Research governance approval has been provided by the Research Governance Office at each site.
Data safety and monitoring
A Data and Adverse Event Monitoring Committee will assess the safety and serious adverse events and will be blinded to the assigned group. Serious adverse events will be given a Severity Assessment Code consistent with incident monitoring in NSW  and reviewed by the Committee. Any perinatal deaths will be analysed to determine whether the model of care contributed.
Interruption of the study
The CIs may terminate this study prematurely, either in its entirety or either of the sites, for reasonable causes (e.g. unsatisfactory enrolment with respect to quantity or quality, inaccurate or incomplete data collection, falsification of records, failure to adhere to protocol). If this occurs, the site investigator will provide written notice to the CIs of the intended termination.