Women’s perception of risk varies according to personal circumstances and previous delivery experiences. While many women describe feeling supported by their obstetrician, many describe uncertainty regarding mode of delivery which may continue even after the birth (Emmett et al., 2006).

Obstetricians advising women often describe the process of CS rather than debating the risks and benefits. CS is recommended more frequently by obstetricians who are male and/or less experienced and/or working in private health care (RCOG, 2001). A large national study found that only 44% of women undergoing CS were offered a trial of labour in subsequent pregnancies. This varied from 8 to 90% in individual hospitals (RCOG, 2001). Most women opted for a repeat elective CS and only 33% chose VBAC. Most obstetricians failed to recognise the degree of their influence over women’s CS/VBAC decision (RCOG, 2001).

Some factors increase the likelihood of CS, including advanced maternal age, body mass index >30, non-white ethnicity, short stature and previous preterm CS delivery (RCOG, 2007). However, there are very few situations where VBAC is not a reasonable option. There are accounts of supportive obstetricians and midwives have enabling ‘higher risk’ women to achieve a safe and satisfying VBAC birth, e.g. twins, breech or two or more previous CS (Lowdon & Chippington Derrick, 2007).

CS and vaginal birth have similar rates of haemorrhage, infection, faecal incontinence, dyspareunia, neonatal mortality (except in breech) intracranial haemorrhage, brachial plexus injuries and cerebral palsy (NICE, 2004). However other risks differ as follows.

Risks associated with VBAC

• The intrapartum infant death risk is small (about 10 per 10 000); however, this is higher than for planned repeat CS (about 1 per 10 000) and is the same as for a primigravida (NICE, 2004).
  
• Vaginal delivery is associated with postnatal perineal pain, increased risk of urinary incontinence and uterovaginal prolapse (NICE, 2004).
  
• Uterine rupture is rare but is marginally increased following induction/ augmentation of labour particularly if prostaglandins are used (RCOG, 2007), possibly following previous ‘single-suture closure technique’ CS (RCOG, 2007) and if conception occurred less than a year following previous CS (Lowdon & Chippington Derrick, 2007).

Risks associated with CS

• Operative risks include bladder/ureter injury, hysterectomy, need for high dependency/intensive therapy and postnatal readmission (NICE, 2004).
  
• Postnatal effects include abdominal pain, slower recovery, longer hospital stay and higher risk of thromboembolic disease (NICE, 2004).
  
• Neonatal risks include neonatal respiratory morbidity, especially pre-39 weeks (Morrison et al., 1995).
  
• Long-term effects of CS include serious risk for subsequent pregnancies: increased risk of placenta praevia, placenta accreta (Langdana et al., 2001) antepartum stillbirth and reduced future fertility (NICE, 2004).

Induction of labour increases the risk of uterine rupture to 80:10 000 if nonprostaglandins are used and to 240:10 000 if prostaglandins are used (NICE, 2004). The rate of vaginal delivery in this group of women is thought to be similar to that quoted for spontaneous labour after a previous CS at about 75% (Vause & Macintosh, 1999).

• Only attempt to induce labour when there is valid indication to do so.
  
• Induction of labour should take place on the labour ward (NICE, 2001).
  
• Artificial rupture of the membranes and/or oxytocin should be used cautiously and selectively (Enkin, 2000).
  
• Also refer to Chapter 18.

A woman who has had a previous CS is considered ‘high risk’ and NICE (2004) advises that labour should take place in a unit with access to immediate CS and on-site blood transfusion services. Women should not be pressured to consent to any particular aspect of care. Since a ruptured uterus is rare, many women undergo ‘routine’ interventions which involve iatrogenic risk and subsequent morbidity.

First stage

One-to-one midwifery care. Continuous intrapartum care is important for recognition and management of uterine scar rupture (NICE, 2004). However emotional support is equally important. Women may approach a VBAC labour with great trepidation. They may have strong memories of a previous long stressful labour perhaps ending in a frightening emergency situation (Horn, 2007). Particular reassurance may be required at the point in labour when the previous CS occurred (Wainer Cohen, 1991). Knowing the reason for the previous CS may even help prevent a recurrence.

Monitoring the fetal heart rate (FHR). RCOG (2007) and NICE (2004) recommend continuous fetal monitoring (CTG) in labour for women aiming for VBAC. Where is no specific FHR or uterine activity pattern that indicates the onset of a uterine rupture, 55–87% cases of ruptured uterus have an abnormal CTG (Guise et al., 2004); often variable and/or late decelerations followed by fetal bradycardia (Menihan, 1999).

Some VBAC support groups challenge this, supporting a woman’s right to choose intermittent auscultation over CTG to increase the likelihood of a normal birth (Beech Lawrence, 2001). A CTG in high-risk women increases labour interventions, including CS, and has not been shown to affect the perinatal mortality rate (Alfirevic et al., 2007). Unfortunately NCT and AIMS receive regular reports of staff acting unprofessionally or threateningly, exaggerating risks and coercing women into CTG monitoring. Any woman who has weighed up her personal risks and declines CTG still needs to be supported in labour as any other and her choices respected. Intermittent auscultation is a valid alternative to electronic fetal monitoring and the FHR should be auscultated particularly scrupulously, especially if there is any suspicion of a problem.

Epidural. Some clinicians recommend epidurals ‘just in case’ a CS is needed and others suggest it could mask the pain of uterine rupture. The RCOG (2007) states that VBAC should not be a contraindication to an epidural. However, women should be aware that epidurals do carry a risk of additional complications and associated interventions (RCOG, 2007) which may complicate an otherwise straightforward labour.

Slow labour. Enkin (2000) suggests that slow progress should not always result in CS: careful oxytocin use following consultant opinion and maternal discussion (RCOG, 2007) may be effective.

• Oxytocin must be titrated to avoid uterine hyperstimulation: contractions should not exceed 3–4 in 10 minutes (RCOG, 2007).
  
• Serial vaginal examination, preferably by the same person, may help assess progress (RCOG, 2007).
  
• Chapter 8 also deals with other methods to stimulate uterine contractions.

Possible precautions

• Intravenous cannula and bloods for full blood count analysis/cross-matching (these can be kept and only tested in an emergency). If the woman declines a cannula, it is quite possible to site one quickly in an emergency, just as for any other emergency CS.
  
• Fasting. Gastric aspiration is associated with poor general anaesthetic technique, not directly due to food in the stomach. Conversely, NICE suggests that the effect of eating in labour on the risk of aspiration under anaesthesia is uncertain. It suggests that women should be informed that having isotonic drinks during labour prevents ketosis without a concomitant increase in gastric volume (NICE, 2004).
  
• Regular antacids (e.g. ranitidine, cimetidine). VBAC women are considered higher risk, and are likely to be offered 4-hourly antacids, although there is no strong evidence to support the use of routine antacids in normal labour to prevent gastric aspiration (Gyte & Richens, 2006).

Second stage of labour

Some suggest too many VBACs are forceps or ventouse assisted as obstetric fear of uterine rupture and lack of confidence in the birth process leads to a desire to conclude VBAC as quickly as possible.

‘If, however, the only reason a speedy delivery is being considered is that the sand in the egg timer has run out, and mother and baby are coping just fine, there is little justification for mending what is not broken’ (Lowdon & Chippington Derrick, 2002).

• Care should be as per a normal second stage of labour (see Chapter 1).
  
• Restricting the duration of the second stage is not evidence based and is associated with increased iatrogenic morbidity for the mother.
  
• Active pushing (valsalva) is potentially dangerous for VBAC women as it includes prolonged breath holding and forced bearing down which carries multiple risks including raised intrauterine pressures.

Third stage

• There are no special precautions if all has gone well.
  
• A scar on the uterus is not a contraindication to a physiological third stage.
  
• If there are difficulties delivering the placenta, consider it may have adhered to the myometrium of the previous scar (placenta accreta). Placenta accreta is only diagnosable and deliverable surgically, sometimes requiring hysterectomy to control haemorrhage (Langdana et al., 2001). Inform the doctor early if the placenta appears retained as bleeding may be concealed. Observe the woman for shock.

Uterine scar rupture

Although uncommon, the uterus can rupture in the antenatal period, at induction, during labour/birth, and even during the third stage of labour.

Be vigilant and listen to the woman. While there is no clinical feature indicative of uterine rupture (RCOG, 2007), many women and midwives report a woman’s unease or distress as a common feature (Lowdon & Chippington Derrick, 2002). If in doubt, contact a senior obstetrician immediately. If at home or a birthing centre, then arrange immediate ambulance transfer to hospital.

For signs and symptoms of uterine rupture and treatment of shock see Chapter 16.

Preparing for birth at home/birthing centre

Each woman has a right to unemotive, unbiased information about the potential risks and benefits within her own individual circumstances. Women who feel pressured, obstructed or unsupported sometimes opt out of the acute hospital system. Most birthing centres do not encourage VBAC, although women may still choose to give birth there. Some NHS midwives are uncomfortable to support home birth VBAC. Women may turn to independent midwives (Lowdon & Chippington Derrick, 2007). However, as discussed in Chapter 6 (Home birth), all midwives have a responsibility to provide care and support at home, even if the pregnancy is not considered low risk. Some suggest that birthing at home can reduce women’s risk of encountering problems since labour and birth at home is physiologically spontaneous and not ‘interfered with’. Conversely, any emergency transfer to an acute unit will obviously involve some delay. So while unlikely, a ruptured uterus is a potentially life-threatening emergency.

VBAC labour care at home

See also Chapter 6.

• Care as per normal labour. The midwife must instil confidence in the woman and strike a balance between maintaining a warm, reassuring persona while also being unobtrusively vigilant for signs of possible rupture.
  
• Ruptured uterus. While there are no reported cases of this occurring at a home birth (Lowdon & Chippington Derrick, 2007), the midwife should be well supported by colleagues and aware of VBAC issues (for signs and symptoms of rupture see Box 16.1, p. 225).
  
• Transfer. The transfer rate for a woman attempting a VBAC at home is thought to be higher than the national average, possibly as midwives and mothers tend to be cautious and transfer at the first sign of trouble. One small study reported a 28% VBAC transfer rate although none was for a ruptured uterus (Chamberlain et al., 1994).

In hospital

• Extra reassurance and one-to-one midwifery care.
  
• Possible precautions: