The National Institute for Health and Care Excellence ([NICE], 2019a) published new intrapartum care guidelines for women with existing medical conditions or obstetric complications and their babies. They contained new guidance for healthcare professionals caring for women in labour who are opting for a vaginal birth after caesarean section (VBAC). The guidelines were welcomed by many in the midwifery profession, primarily due to their individualised and more woman-centred approach.
Globally, increasing numbers of women are undergoing caesarean section (Boerma, 2018), with the potential for many of these women to go on to give birth to subsequent children. Determining whether women are suitable for a trial of labour after caesarean section (TOLAC) is a vitally important area of obstetrics and midwifery (Robson et al, 2015). Balanced counselling to aid women's choice is particularly important as data suggest that common interventions in childbirth, such as caesarean section, are associated with poorer long-term health outcomes (Clark and Silver, 2011).
VBAC is a widespread occurrence on any labour ward in the UK, and midwives are frequently exposed to this realm of midwifery care. Under the Royal College of Obstetrics and Gynaecologists' ([RCOG], 2015) guidelines, women choosing VBAC should be advised to have their labour care conducted in a unit with facilities for emergency caesarean and advanced neonatal resuscitation. Midwifery-led units are seeing an increasing number of women choosing to have their babies in such settings, but at present, no data appears to have been collated. There remains no published national data regarding VBAC at home, which is, in our experience, an increasingly popular trend. However, this practice occurs following consultation with either a senior obstetrician, midwifery matron or consultant midwife, and in partnership with the woman and her birth partners. This article outlines the history of VBAC, discusses current practice, and explores the statistics and clinical outcomes for mother and baby, with the aim of providing an overview of VBAC and providing a commentary on the new guidelines for practice.
The past
The practice of VBAC has become of increasing interest in maternity care over several decades. The notion of ‘once a caesarean, always a caesarean’ (Cragin, 1916) dominated obstetric practice throughout the 20th century. However, a shift in practice during the 1980s to mid-1990s saw this notion questioned, resulting in a subsequent rise in women choosing VBAC and a drop in caesarean section rates (Habak and Kole, 2018). Despite this change in attitude and practice, worldwide rates of VBAC have shown a downward trend. Historically, VBAC attempts in the UK fell from 48.3% in 2000 to 30.7% in 2002, with a 73.4% success rate of vaginal birth (Landon et al, 2004). Furthermore, actual VBAC rates fell from 45.9% in 1988 to 36% between 2004 and 2011 (Knight et al, 2013). Despite the widely publicised safety of VBAC, these rates have never fully recovered.
There is consensus between NICE, the RCOG, and the American College of Obstetricians and Gynaecologists (ACOG) that a planned VBAC is clinically safe for the majority of women who have a history of one previous lower segment caesarean section (RCOG, 2015). Despite a high emphasis on VBAC in the UK's current NHS practice, there is little recently published data to inform women and clinicians of the uptake and success rates of VBAC, despite lower financial costs for providers and the NHS, and fewer maternal complications and morbidities that are associated with a vaginal birth (RCOG 2015).
The present
Contemporary practice of uptake and subsequent success of VBAC is poorly documented in terms of national data and few recent reports are available for comparison. The RCOG (2015) noted that the success of planned VBAC varies between 72-75% for a woman following one caesarean section, which increases to 85-90% success in women who have a history of one vaginal birth alongside with one caesarean section. Knight et al (2013) published the first national cohort study attempting to describe statistics regarding attempted and successful VBAC, suggesting that just over 50% of women with a primary caesarean section who are clinically eligible for a TOLAC attempted a VBAC in their subsequent pregnancy. Their findings highlighted that within this 50% of women, approximately 33% were successfully delivered vaginally, although unsuccessful VBAC was more common in those with advanced maternal age, obesity, high birth weight, a previous caesarean for dystocia, and non-white ethnicity (Knight et al, 2013).
In current practice, women are generally offered the option of a VBAC in the absence of morbidity following their first delivery with no significant medical or surgical history, an uncomplicated pregnancy, and a history of one previous caesarean. Women's birth preferences and wishes should be respected, and women wishing to exercise their autonomy should be treated with a non-judgemental and supportive approach (Dexter et al, 2013), as per the NHS Constitution (Department of Health & Social Care, 2015). Each woman's decision regarding her choice for a subsequent mode of birth may be influenced by many factors. These may include her previous labour and delivery experience, her desire to achieve a vaginal birth, feelings regarding a subsequent caesarean section, and family considerations (Dodd et al, 2013). Mothers may have potentially made their decision based on their previous experiences alone and purely seek support from their midwives regarding this decision (Guise et al, 2010). For women meeting the above criteria and who make this choice, there is a consensus that repeated caesarean section can be associated with higher morbidity and mortality in comparison to a trial of labour after caesarean.
VBAC and subsequent caesarean section both have their risks and benefits. Repeat caesarean is associated with an increased risk of postpartum haemorrhage, requirement for blood transfusion, infection, bowel and bladder damage, and deep vein thrombosis (Dodd et al, 2013). Furthermore, the neonate may be at risk of respiratory complications (Crowther et al, 2012), especially if delivered before 39 weeks without antenatal corticosteroids (RCOG, 2015).
Typically, there are fewer risks associated with successful VBAC. There is reported to be a 0.5% risk of uterine scar rupture which may potentially result in acute fetal hypoxia and brain injury, and an increased incidence of instrumental delivery of up to 39% (Hehir et al, 2014). However, these morbidities are lower in women who have a successful VBAC as opposed to a repeat elective caesarean; despite these risks of scar rupture or dehiscence, this should be balanced against a reduction in overall morbidity when VBAC is successful (Rossi and D'Addario, 2008). Overall, women should be informed that successful VBAC has the fewest complications, but also that the most significant adverse outcomes occur when a woman requires an emergency caesarean following a TOLAC (RCOG, 2015).
The future? How NICE guidelines can inform midwifery practice
This article focuses on four recommendations drawn from the NICE 2019 guidelines; intrapartum care for women with existing medical condition or obstetric complications and their babies, and discusses their implications for clinical practice. It is important to note that in their gathering of evidence, NICE (2019b) acknowledged that the quality of guidelines concerning VBAC was very low according to the grading of recommendations, assessment, development and evaluations (GRADE) criteria. Most studies were cohort or retrospective studies, and no randomised control trials (RCT) were located. Therefore, some elements of the new guidelines are based on the knowledge, expertise and experience of the panel, which may have the potential to be influenced by personal experience and views.
Routine intravenous (IV) cannulation
Although there was no explicit evidence available to assess harm versus benefit, based on the panel's clinical experience and expertise, it recommended that IV cannulas should not be routinely offered to women undertaking a TOLAC. IV cannulas can be a frequently unwanted intervention in labour. They can be painful, restrictive for women in labour, and a source of infection. Although some maternity units already adhere to this recommendation, it is still common practice on many labour wards to routinely cannulate women having a TOLAC and it may take some time to change the culture on obstetric labour wards.
Fetal monitoring
Contrary to earlier reports, the NICE 2019 guidelines continue to recommend the use of continuous electronic fetal monitoring, such as cardiotocography (CTG), for women attempting a TOLAC. However, NICE acknowledges that evidence around this topic is scarce regarding risks and benefits of continuous fetal monitoring, and whether it improves outcomes for mother and baby, or leads to unnecessary intervention, compared to intermittent auscultation.
There is little acknowledgement of the lack of evidence for CTG in maternity policy, which is complicated further by a lack of evidence regarding intermittent auscultation (IA). Regarding CTG interpretation for women choosing a TOLAC, studies have noted a trend of fetal tachycardia, reduced variability and significant variable decelerations in cases of uterine rupture, alongside other findings such as loss of station (Andersen et al, 2016; Desseavue et al, 2016). Despite these correlating findings, there is an acknowledged association with unnecessary intervention and limitations, however CTG remains the best tool currently available and is thus recommended.
NICE (2019b) recommended the undertaking of an RCT to compare continuous fetal monitoring with IA for women in labour who have had a previous caesarean section. It proposed that such a trial should –evaluate clinical and cost-effectiveness and consider both short-and long-term outcomes such as mortality in the baby, neonatal unit admission, a requirement for respiratory ventilation, development of neonatal encephalopathy, developmental delay at two years, caesarean section, and woman's experience of labour and birth'. A cost-benefit analysis should additionally be undertaken to review the cost-effectiveness of CTG versus IA in VBAC.
Analgesia
NICE recommends that women undertaking a VBAC should be offered a full range of analgesic options, which includes birthing in water. It stated that –no evidence was identified for inclusion for this aspect of the review, the committee strongly agreed that an absence of evidence in support of using the birthing pool should not be interpreted as meaning that labour and birth in water is contraindicated for this group of women' (NICE, 2019).
Therefore, maternity units may need to consider the implementation of birthing pools into labour wards to ensure the full range of analgesic options are available, along with telemetry machines to ensure adequate fetal monitoring, and thus both the above recommendations are considered. This provision may additionally improve women's experience if a comprehensive range of birth options are available and may influence women's decisions to undertake a TOLAC.
Counselling women about their birth choices
When discussing the mode of delivery, maternal choice and preferences must be considered. While national drivers are pushing maternity services to reduce their caesarean section rate, clinicians must respectfully consider maternal preferences and priorities. Evident from guidelines is the need to counsel women effectively about their birth choices around VBAC. NICE (2019) states that in order to make an informed choice regarding the mode of delivery, women should be given clear and accurate information to aid decision making, with specific discussions taking place at various points throughout pregnancy and during labour.
Firstly, before labour, women should be counselled that there is little evidence of a difference in outcomes for babies between vaginal birth and caesarean section. Women are at a lower chance of complications if they have had a previous vaginal birth as well as a caesarean section, as previously outlined. It is important that women are informed of the small chance of uterine rupture, and a requirement for emergency caesarean section, both which may result in a higher incidence of heavy bleeding requiring a blood transfusion, infection, extended hospital stay, and complications in future pregnancies, including placenta praevia or accreta.
Secondly, women should be counselled during labour. It is essential that further discussions take place to inform women of new risks if they arise, for example, when discussing the use of syntocinon or epidural anaesthesia. It is necessary to explain that oxytocin infusion increases the chance of uterine rupture and increases the chances of an emergency caesarean section compared with spontaneous VBAC (RCOG, 2015), and that epidural alone does not increase their chances of a repeat caesarean, but does increase their likelihood of an instrumental delivery (Grisaru-Granovsky et al, 2018). This continuous conversation allows decisions to be made in partnership between the women and their birth partners throughout all aspects of their care.
Conclusion
There are several subtle changes to the NICE guidelines published in Spring of 2019, which we see as promoting a more woman-centred and less medicalised experience of VBAC. However, it may be useful when explaining risks and benefits of a TOLAC to women, if we as practitioners are equipped with knowledge of the increased or decreased risks. Many women and their partners may wish to know the evidence or statistics about risks versus benefits to aid decision making.
This information must be based on the best available evidence with an acknowledgement of the limitations of the evidence, presented in an unbiased and impartial way to ensure informed choice. Infographics may help with this, as well as patient information leaflets sharing clear and current evidence-based advice. Furthermore, women may be able to make an informed decision, and midwives and obstetricians may be able to counsel women more effectively, if VBAC success rates were more easily accessible. It would be helpful to have access to such data from NHS England and NHS Improvement covering VBAC attempts and success rates from its annual publications of birth rates.