Rates of caesarean section worldwide remained stable at under 10% until the 1980s when they started to rise, reaching 30% of births in many developed countries in the last decade. It is predicted that by 2020 the caesarean delivery rates in the USA could be higher than 50% (Solheim et al. J Matern Fetal Neonatal Med 2011;24:1341–6). A similar but even more marked trend is also seen in many low-income countries. Because of an increase in the incidence of placenta praevia and placenta accreta, with the associated maternal morbidity and mortality, high caesarean birth rates have become a matter of concern to international public health authorities. In an attempt to mitigate the rapid increase in caesarean delivery and related costs, many clinics and hospitals around the world are now offering antenatal classes to promote vaginal birth after caesarean delivery (VBAC).
The main risk of VBAC is uterine rupture during labour, and professional societies recommend that VBAC should be conducted in hospitals where staff can provide emergency care (Scott Obstet Gynecol 2011;118:342–50). In Schreiber versus Physicians Insurance Company of Wisconsin (Supreme Court of Wisconsin, no. 96–3676, January 1999), a patient with two previous caesareans, one for failure of labour progress and another elective, was consented for VBAC. Four hours after the start of spontaneous labour, she told her obstetrician that she had changed her mind, wanted to abandon the VBAC and instead have another caesarean delivery. Despite the mother experiencing severe abdominal pain and requesting a caesarean, the obstetrician continued to pursue VBAC. About 12 hours after admission, the fetal heart rate pattern became abnormal and at emergency caesarean the uterus was found to have ruptured. The child was born alive but was later diagnosed with cerebral palsy (spastic quadriplegia). The court concluded firstly that the obstetrician had violated the mother's right to informed consent by refusing to follow her clearly communicated choice of treatment during labour, and secondly that the plaintiff was entitled to damages because of the doctor's failure to conduct a new informed consent discussion.
The consent procedure for caesarean section is well established and many professional societies publish guidance and printable documents that can be used to obtain properly informed consent, including a detailed description of the serious and frequent risks associated with caesarean delivery. However, similar documents are not available for VBAC. The risk of operative complications associated with an elective caesarean section will depend on the indication for the procedure. For example, placenta praevia carries a higher risk of peripartum complications than breech presentation. Similarly, in VBAC, the risk of rupture may vary with the indication for the initial caesarean delivery, and will also change depending on the progress of labour and the use of uterotonics (prostaglandins, oxytocin). This highlights the need for national and international guidelines on informed consent for VBAC, including the possibility of patient withdrawal of consent during labour.