What are the chances of having a vaginal birth if you have had more than one caesarean section, it is an approximately 70-75% chance of achieving a vaginal birth. The evidence available in recent and past research would suggest that you have an excellent chance of achieving a vaginal birth if you have no pre-existing conditions that would place you at higher risk of not achieving a vaginal birth or would indicate a repeat caesarean. These type of conditions are as follows:-

• Placenta Praevia - indicated by ultrasound in the later part of pregnancy. A low lying placenta in early pregnancy does not mean you will have placenta praevia, placenta's usually move as the uterus grows larger with the baby. Placenta Praevia must be a caesarean section as the placenta is covering the cervix, it is also performed before you are able to go into labour, as any disturbances to the placenta could place your baby at risk.
• Classical Scar - it is the policy of many obstetricians not to allow women with a classical caesarean incision to undergo an attempt at vaginal birth after caesarean. This is due to the higher risk of uterine rupture, as the scar is through the higher part of the uterus which is under more use during labour. The lower segment of the uterus does not contract greatly during labour as the contractions come from the top of the uterus (fundus) forcing the baby down and out.
• Placenta Accreta - this is where the placenta actually embeds into the exterior of the uterus, usually into surrounding organs such as the bladder or bowel. It is a very serious condition for the mother, and is often due to previous scarring on the uterus either from uterine surgery or a previous caesarean.
• Foetal Malpresentation - the baby may be in an awkward position that will make it impossible to be born vaginally. For example a brow presentation is where the baby is facing the cervix. A footling breech (quite different to a frank or complete breech) may also be a contraindication as there is more risk of the umbilical cord coming before the baby.
• Previous uterine rupture
• True Cephalopelvic Disproportion - this is a commonly over diagnosed condition, the only true test of a pelvis adequacy for each individual baby is to attempt a vaginal birth. It does occur, but is quite rare.
• Severe Pre-Eclampsia
• Other obstetric reasons.

THE RESEARCH

Effective Care in Pregnancy and Labour Enkin et al
The overall vaginal delivery rate is little different than that of women who have only had 1 caesarean. It ranges from 58% to 81% of women who attempt it. One of those studies includes women with 3 or more caesarean sections with an 88% success rate (8 women attempted and 7 succeeded). The dehiscence of uterine scar was slightly higher than for women with 1 caesarean, but they were all asymptomatic with no serious sequelae.

Vaginal birth after cesarean Phelan et al
American Journal of Obstetrics and Gynecology, Vol 157 No. 6 December 1987
In a study of VBAC in which women with 2 caesarean sections were included in the trial of labour (a term we abhor) the following data was found:-

Comparison of Morbidity and Hospital stays for study groups

Comparison of Morbidity in Trial vs No Trial study groups

Success rates of vaginal delivery after two previous caesarean sections were 70% for the years 1982-1983 and 72% for the years 1983-1984, the success rate for women after three previous caesareans was 100% and 88% respectively.

VBAC- A 10 year experience Miller et al
Obstetrics & Gynecology, Vol 82 No 2 August 1994
This trial found the following data:-

The data unfortunately does not reveal if these labours were induced or augmented, which is now a known risk factor for rupture.

Trial of Labor following Cesarean Delivery Cowan et al
Obtetrics & Gynecology vol 83 No. 6 June 1994
Number of previous abdominal deliveries a patient had undergone did not seem to affect her chance of delivering vaginally, when given a trial of labor. Women who had 1, 2 or 3 previous caesareans had vaginal delivery success rates of 81, 77, and 100% respectively. This seems to indicate that there is little or no loss of scar strength with repeat cesarean deliveries, and that the number of previous cesareans should not be a factor in selecting women for trial of labour.
Successful trials of labour also were significantly advantageous due to less maternal blood loss than repeat caesarean.
Babies all had apgars of over 8, apart from 5 ruptures, a rupture rate of 0.8% in the study and 1 infant suffered sever neurologic sequelae.

VBAC - Results of a 5 year multicentre collaborative study Flamm, et al
Obstetrics & Gynecology, Vol 76. No. 5 Part 1 Nov 1990
During the next 3 years (after 2 years another 2 hospitals joined the trial) there were, 106,261 births, including 10,169 to women with a history of one or more cesarean operations. From this group a subgroup of 3957 women (38.95) attempted labor, of these 2977 (75.2%) delivered vaginally.
During the first 2 years of the study, of the 89 trial of labour patients with more than one previous cesaran, 68 (76%) delivered vaginally. During the subsequent 3 years, the vaginal birth rate in this group was 64% (100 of 156). Overall of the 245 patients who underwent a trial of labor after more than 1 cesarean, 168 (69%) delivered vaginally. The incidence of uterine rupture in this group did not differe significantly from that in the group of patients with one previous cesarean.

Trial of Labour after 4 Caesarean Sections: A case report and literature review Wood et al
Australian and New Zealand Journal of Obstetrics and Gynaecology 2001 41:2 233-35

This occurred at Flinders Medical Centre in Adelaide, South Australia.
Clinicians should support a woman's request for a trial of labour, regardless of the number of previous caesarean sections, provided she has been provided with accurate information on outcome and risk.

Successful vaginal birth after three previous Caesarean sections with no prior labour
Lucy Bowyer and Michael Chapman ANZJOG VOL 43 Dec 2003 pg 471

Vaginal birth after Caesarean section is in danger of becoming extinct. Despite the spectre of litigation and bankruptcy we should maintain an evidence-based, rather than a litigation fearful, practice. To this end the present case illustrates the application of the best available evidence to a clinical challenge.

Case Report A 36-year-old woman consulted for a second opinion at 32 weeks' gestation in her fourth pregnancy. The woman wished to have a vaginal birth, having previously had three lower segment Caesarean sections. Her pregnancy had been uncomplicated with no vaginal bleeding; she was fit and well with a low body mass index.Her first baby (male 3.62 kg) was delivered in South Africa in 1994 by elective Caesarean section with an ante-partum diagnosis of 'cephalo-pelvic disproportion'. Her second baby (female 3.24 kg) was delivered by elective Caesarean section, again in South Africa, in 1996 for the indication of previous Caesarean section. In 1998 she and her family moved to the UK, she was keen to attempt vaginal birth and this was agreed provided that she laboured spontaneously before 42 weeks' gestation. At 42 weeks she had a third elective Caesarean section (female infant, 3.24 kg), as spontaneous labour had not occurred.The patient was very unhappy with the conduct of her previous deliveries. On each occasion the epidural had been difficult to insert, a spinal tap had occurred with the first baby and she felt bereft that she was unable to hold her babies (beyond the brief standard initial contact) and keep them with her. The consultation with her involved a review of published reports examining births after two or more previous Caesarean sections. It was obvious that she and her husband were already well informed with regard to the likely success of vaginal delivery and the possible uterine rupture rates. The opinion offered was a 60% chance of vaginal birth and a 3% risk of scar rupture with subsequent serious consequences. It was agreed that, after 6 h of active labour, if progress was poor then a Caesarean section would be advised. The risk of placenta praevia and percreta was discussed, and ultrasound revealed a posterior placenta well clear of the lower segment. As they wished to accept the risks involved, a vaginal birth after three previous Caesarean sections was planned at St. George Hospital, New South Wales, Australia. It was agreed that continuous fetal monitoring would be carried out throughout labour, if after 6 h of active labour delivery was not imminent then Caesarean section would be advised. At the 37-week visit the fetal lie was oblique; subsequently the lie became longitudinal with a cephalic, but unengaged, presentation at term.As she had been having short-lived contractions irregularly through the night and was fearful that intervention would be suggested she did not attend for her 41-week visit. However, she was persuaded to attend for an antenatal 42-week consultation. She had been having contractions overnight with only mild pain and felt well. The cervix was posterior, soft, 50% effaced and closed, the fetal vertex was 2 cm above the ischial spines, fetal movements and heart rate were normal. The increased risk of unexpected stillbirth as gestation prolongs was discussed, and she declined fetal ultrasound or cardiotocography.The following day at 42 weeks and 1 day gestation, she arrived in hospital in the evening, having had contractions that had become more painful and more regular throughout the day. On examination the cervix was 8 cm dilated, fully effaced and the fetal head at the ischial spines. She proceeded to have a normal vaginal birth 90 min later with a right medio-lateral episiotomy. A live male infant was born in excellent condition, weighing 3.565 kg. She and her husband were delighted with the outcome and she was discharged home on the early discharge program the following day.

Discussion The largest reported series on birth after two or more previous Caesarean sections was by Miller et al. 1 Miller et al.'s study was conducted over a 10-year period in California and included 1586 women with two previous Caesarean sections undergoing a trial of labour; 1.8% (29) of these women had a uterine rupture, with one rupture-related perinatal death (0.63:1000). There were 241 women who had a trial of labour with three or more previous Caesarean section scars, with a rupture rate of 1.2% (three) and no perinatal deaths. The success of trial of labour in these groups was 75% and 79%, respectively. Within the same series the success for vaginal birth after Caesarean section with only one scar was 83% with a 0.6% uterine rupture rate and 0.18:1000 perinatal deaths, thus uterine rupture was more common in women with two or more Caesarean section scars. The maternal morbidity and hysterectomy rates are not stated in Miller et al.'s publication. There was one rupture-related maternal death giving a rupture-related maternal mortality rate of 7.9 per 100 000 trials of labour and a 5.1% risk of perinatal asphyxia as a consequence of uterine rupture.The second largest series was by Phelan et al. and conducted over a 4-year period in California. 2 Trial of labour after two previous Caesarean sections was attempted by 501 women, with a 69% successful vaginal delivery rate. The uterine dehiscence rate is reported as 1.8% (less than the control group of repeat Caesarean sections who had a 4.6% dehiscence rate, with one uterine rupture), with no uterine ruptures and one hysterectomy carried out for uterine atony. The perinatal mortality rates from Phelan et al.'s series are hard to interpret as they included some very low birthweight infants (320 1990 g), but overall the perinatal mortality rate was comparable between women who did and who did not attempt a trial of labour. There were no maternal deaths. Interestingly, there were 85 women who had undergone a trial of labour in both previous pregnancies and, of these women, a trial was successful upon the third occasion in 53% (45) of cases.Undoubtedly a woman who has two or more previous Caesarean section scars in her uterus is at greater risk of uterine rupture than a woman who has only one scar. Appleton et al.'s Australian series estimates a rupture rate of 0.3% for women with one prior scar; thus there is a sixfold likely increase in the risk of uterine rupture in a woman with two previous scars, although the absolute figures are still only 1.8 per 100. 3 It is important to emphasise the serious consequences of rupture when counselling the individual woman. Where there are two previous Caesarean section scars, there is an approximate 2% risk of rupture necessitating hysterectomy and the possibility of fetal death. However, in the published reports these figures do not differ greatly from those women undergoing elective repeat Caesarean section, and should not exclude a trial of labour after two or even three previous Caesarean sections if that is what the fully informed individual woman desires. We must be aware of our limitations as clinicians to be all-protective and offer the best available advice from the best available evidence to our patients.

1. Miller DA, Diaz FG, Paul RH. Vaginal birth after cesarean: a 10-year experience. Obstetrics Gynecol. 1994; 84: 255 258
2. Phelan JP, Ahn MO, Diaz F, Brar HS, Rodriguez MH. Twice a cesarean, always a cesarean? Obstetrics Gynecol. 1989; 73: 161 165
3. Appleton B, Targett C, Rasmussen M, Readman E, Sale F, Permezel M. Vaginal birth after Caesarean section: an Australian multicentre study. VBAC Study Group. Aust NZ J Obstet Gynaecol. 2000; 40: 87 91