Research published by the World Health Organization (WHO, 2021) has shown that caesarean section incidence is globally increasing from 7% in 1990 to a current 21% of all births, with an estimated rise to 29% by 2030 (Betran et al, 2021). In some countries, the incidence of lower (uterine) segment caesarean section already outnumbers the incidence of vaginal birth, with wide variation between countries in incidences, some having rates as high as 43% (Betran et al, 2021). UK statistics presented by the National Maternity and Perinatal Audit Project Team (2019) suggest an overall caesarean section rate of 25.8%, (11.3% elective, 14.5% emergency), with incidence rates for multiparous women and birthing people 15.7% (elective) and 9.4% (emergency). The report indicates that the overall rate of vaginal birth after caesarean is 24.5% (this figure limited to secundiparous women).
While the WHO (2018) has published strategies to reduce unnecessary caesarean section rates, the last few years have seen UK national drivers to reduce caesarean section rates come under intense scrutiny. In particular, findings of the report of the investigation into Morcambe Bay (Kirkup, 2015), the interim findings of the Independent Review of Maternity Services at the Shrewsbury and Telford Hospital NHS Trust (Ockenden, 2020) and evidence submitted and subsequent report into the safety of maternity services in England (Health and Social Care Committee, 2021) have highlighted the problematic nature of the Red-Amber-Green rating for caesarean section as a metric against which performance is measured, compared and benchmarked, as well as challenging the use of strategies to reduce the likelihood of unnecessary operative birth.
The WHO (2021) acknowledges that caesarean is, in all arenas, a lifesaving intervention, particularly where support to birth vaginally would pose risks outweighed by those of a lower (uterine) segment caesarean section, and that ‘timely access (is available) for all women’. However, they also acknowledge that not all are undertaken for medically indicated reasons and that the procedure itself is not risk free and therefore can be harmful in both the long and short term for both the woman and their baby.
Therefore, it is essential that decision making in terms of mode of birth after a previous caesarean is truly informed and based on best available evidence, provided to the person in a non-coercive, balanced manner. In the UK, the Montgomery v Lanarkshire Health Board (2015) ruling was a landmark in redefining the standard for informed consent and disclosure, particularly in relation to an open, balanced and non-biased presentation of benefits and material risks for all recommended interventions, treatments, choices and alternative, taking into consideration that the person may decide they do not want to be informed. Any judgement made in relation to the information provided is dependent on a mutually respectful relationship between caregivers and patients to ensure that exploring the individuals' values, wishes and needs supports identification of that person attaching significance to any risk presented (Montgomery v Lanarkshire Health Board, 2015).
A person who is giving birth has a right to decide where they birth and cannot be compelled to accept a recommended mode or place of birth (Birthrights, 2017; 2018). At all times, caregivers should respect the person's preferences for exercising autonomy in a non-judgemental and supportive way, regardless of the decision and whether or not the choice is one that is felt to be the most ‘wise’. This should be the case regardless of whether the decision is to have a repeat elective caesarean section or planned vaginal birth after previous caesarean (Human Rights Act, 1988; Mental Capacity Act, 2008; Dexter et al, 2014; Montgomery v Lanarkshire Health Board, 2015).
Taking all this into consideration, the National Institute for Health and Care Excellence (NICE, 2021a; 2021b) have recently published updated guidance for the management of caesarean birth and shared decision making, while other existing guidelines continue to inform clinical practice and influence at a local level (NICE, 2008; 2017; 2019; Royal College of Obstetricians and Gynaecologists (RCOG), 2015). When discussing pregnancy and childbirth after a previous caesarean section, consideration should be given to exploring maternal preferences and priorities for birth while offering a discussion of both the benefits of repeat planned caesarean section and planned vaginal birth. This should include the likelihood of unplanned caesarean birth and an exploration of contraindications for planned vaginal birth (Box 1). Maternal outcomes, risks and benefits of repeat planned caesarean section and planned vaginal birth are varied and dependant on a variety of maternal and clinical factors, including but not limited to spontaneous labour onset, body mass index, number of previous caesarean sections, timing and clinical indication for previous caesarean section and any previous vaginal births. Skilled history taking by clinicians will ensure that such factors are taken into consideration and provide an individualised approach to counselling patients to support their preferences for the current pregnancy and present success rates, risks and benefits.
Box 1.Contraindications to planned vaginal birth after previous caesarean section
- Previous uterine rupture
- Classical caesarean scar
- Major placenta praevia, accrete, percreta
- Maternal refusal
(Royal College of Obstetricians and Gynaecologists, 2015)
Success rates
Planned successful vaginal birth overall presents the fewest complications past 39 weeks' gestation with a single previous caesarean section and remains a suitable and clinically safe option for those with a singleton cephalic pregnancy past 37 weeks (RCOG, 2015). However, the risk increases when attempted vaginal birth then subsequently results in a repeat caesarean section. The likelihood of success is between 72–75% (Mozurkewich and Hutton, 2000; Guise et al, 2004), rising to 85–90% with a single previous lower (uterine) segment caesarean section and at least one previous vaginal birth (RCOG, 2015), reducing to 71.1% with two previous caesarean births (Tahseen and Griffith, 2010). For people with a combination of comorbidities, the likelihood of a successful planned vaginal birth can be as low as 40% (Landon et al, 2004; 2005; RCOG, 2015). A study exploring the likelihood of success and morbidities in women and birthing people with three or more previous caesareans found that rates of success (both in planned vaginal birth and repeat planned caesarean section) were similar to those who had one previous caesarean (Cahill et al, 2010). However, current RCOG guidance suggests senior obstetric input for individualised assessment of risk and supported decision making (RCOG, 2015)
Uterine rupture and dehiscence
For many, discussions of risk revolve around that of uterine rupture. While the likelihood is low in many cases, the severity of outcome in terms of maternal mortality and fetal mortality and morbidity can be significant. For a repeat planned caesarean section, the likelihood of uterine rupture is <0.02% (<2 in 10 0000), rising to 0.5% (1 in 200) in an uncomplicated planned vaginal birth and 1.36% with two previous caesarean sections (Tahseen and Griffith, 2010; RCOG, 2015). Where labour is then to be induced or augmented, this has the effect of raising the likelihood of rupture to 0.54–0.14% and 0.9–1.91% respectively (Landon et al, 2004; Fitzpatrick et al, 2012; Stock et al, 2013; Wallstrom et al, 2018).
Maternal and perinatal morbidity and mortality
Caesarean section is major abdominal surgery and presents the risk of morbidity and mortality associated with the procedure, post-surgery complications and effects on future pregnancies. Of note are the overall rates of mortality, which are 0.013% or 13 in 100 000 compared with 0.004% or 4 per 100 000 in planned vaginal birth, needing a blood transfusion (although Hammad et al (2014) suggests the likelihood is halved compared to planned vaginal birth at 1% vs 2%), post-surgery infection, deep vein thrombosis, bowel and bladder damage, longer recovery and effects on the ability to care for a neonate once born. In relation to future pregnancies, the risk of placenta praevia associated with caesarean section increases in line with one, two or three uterine scars (1%, 1.7% or 2.8% respectively) with a likelihood of placenta accreta up to 67% in women with placenta preavia and five or more previous lower (uterine) segment caesarean section (Guise et al, 2004; Gurol-Urganci et al, 2011; RCOG, 2015). Of course, planned vaginal birth is not without risk, with the likelihood of anal sphincter injury around 5% (Hehir et al, 2014), alongside a reduction in the change of pelvic organ prolapse and incontinence. Instrumental birth is also a potential risk factor (39%) alongside the baseline risk factors always associated with vaginal birth.
The RCOG (2015) green top guideline for birth after previous caesarean suggests that women should be advised that the overall likelihood of birth-related perinatal mortality with planned vaginal birth is very low and comparable with that of nulliparous woman in labour (Smith, 2001). This is acknowledging the risk of morbidity association with hypoxic ischaemic encephalopathy for planned vaginal birth compared to repeat planned caesarean section (0.08% or 8 in 10 000 vs 0.01% or <1 in 10 000) and transient respiratory issues is increased in repeat planned caesarean section (4–6% vs 2–3%) (RCOG, 2015)
Place of birth
Current UK-based guidelines recommend that for women planning a vaginal birth after a previous caesarean (not considered low risk), they birth in a clinical environment (preferably a delivery suite) that has access to appropriate staffing and equipment, including continuous monitoring, continuous intrapartum care and resources for immediate caesarean birth, blood transfusion facilities and advanced neonatal intervention should this be required (RCOG, 2015; NICE, 2017; 2019). The purpose of continuous monitoring is related to the monitoring of signs and symptoms of uterine rupture (Box 2) (Desseauve et al, 2015; Andersen et al, 2016) and swift access to measures to manage this in an emergency. Dunning et al (2019) have previously discussed how the NICE recommendations for continuous electronic fetal monitoring in the absence of other effective tools continues to be the recommendation despite the known limitations of interpretation and increased likelihood of intervention, as well as a paucity of high-quality evidence supporting continuous electronic fetal monitoring and intermittent auscultation.
Box 2.Clinical features of uterine scar rupture
- Abnormal cardiotocography/changes in cardiotocography
- Inability to pick up fetal heart rate at previous transducer site
- Uterine activity significantly changes or ceases
- Maternal tachycardia, hypotension, evidence of shock, syncope
- Severe and persistent abdominal pain
- Acute onset scar tenderness or pain
- Vaginal bleeding
- Haematuria
- Change in abdominal shape and contour
- Loss of station of presenting parts
- Palpable fetal parts in maternal abdomen
(adapted from RCOG, 2015)
Many people are now choosing to plan a vaginal birth after caesarean at home. Although little evidence overall exists for outcomes for planning a vaginal birth after caesarean at home, anecdotally the phenomena is becoming progressively more popular. A 2017 study using a secondary analysis of data from the Birthplace study (Birthplace in England Collaborative Group, 2011; Hollowell et al, 2015) aimed to compare vaginal birth rates in the 1% of women in the data set planning birth at home after a caesarean section and those planning birth in an obstetric unit after a caesarean section (Rowe et al, 2016). The study found that compared to those planning birth in an obstetric unit, women planning birth after caesarean section at home were statistically more likely to have a vaginal birth, although transfer rates for women planning a birth after caesarean section at home were 37.2% (intrapartum and postnatal combined), varying in rate according to parity (56.8% para 1 and 24.6% para 2 or above). Adverse maternal outcomes occurred in 2–4% of births with a similar number of neonatal unit admissions, although this was similar for both planned home birth and obstetric unit birth after a caesarean section. A Canadian study exploring differences between maternal and neonatal outcome between planned home birth after a caesarean section and planned hospital vaginal birth after a caesarean section found that planned home birth was accompanied by a 39% reduction in the odds of having another caesarean birth compared to women planning birth in hospital after caesarean section, with severe adverse outcomes being rarely realised (Bayrampour et al, 2021). The effect of confident, competent and clinically skilled caregiver support and the environment in which the birth takes place undoubtedly has an effect on progress in labour (Wickham, 2021). Additionally, international research continues to emerge to inform clinicians and policy makers around the influences and motivations for choosing home birth after a caesarean section (Keedle et al, 2015) as well as water vaginal birth after a caesarean section (McKenna and Symon, 2014), which of course can be facilitated at home or on an obstetric unit. This is compelling evidence indeed, however, birthing at home after caesarean is rarely offered as an option, particularly given clinician anxiety around providing what is considered out of guidelines or high-risk birth at home, as well as a paucity of support through national and local guidelines.
Conclusion
Current global trends and national agendas can make discourse around repeat planned caesarean section and planned vaginal birth for clinicians challenging. However, in order to maintain a professional and supportive environment, clinicians should remain informed and skilled in counselling and supporting informed decision making. Safe and effective maternity services in relation to birth after caesarean must be first and foremost based upon best available evidence, a foundation of mutual respect for decision making, free of coercion and rooted in the individual's values, wishes and needs. People should be able to be able to make an informed decision, supported by knowledgeable and non-judgemental clinicians who understand.
Key points
- Individual motivations for choices for birth after caesarean section are highly individual and should be explored sensitively to identify individual needs, preferences and what is materially important to the person giving birth
- All clinicians should remain up to date and informed when providing information that supports decision making, being careful not to influence based on opinion
- Vaginal birth after caesarean is a safe option for most women, taking into consideration individual factors and should be supported if requested
- Repeat elective caesarean section is a viable and appropriate choice for many people and should be supported if requested
- People considering either repeat elective caesarean section or planned vaginal birth/vaginal birth after caesarean should be signposted to information sources that reflects contemporary evidence
- Multidisciplinary team working should be encouraged to foster relationships across teams to support effective supported decision making