1Department of Obstetrics & Gynaecology, Sultan Qaboos University Hospital; Departments of 2Obstetrics & Gynaecology and 3Family Medicine & Public Health, College of Medicine & Health Sciences, Sultan Qaboos University, Muscat, Oman *Corresponding Author e-mail: drriyami@hotmail.com استخدام قثطار فويل داخل عنق الرحم لتحريض املخاض حلاالت القيصرية السابقة جتربة أحد مراكز الرعاية الثالثية يف عمان ه�زل غون�ش�لفي�س, نه�ل الري�مية, متيمة الدغي�شية, فيداي�ن�ث�ن غوري, حممد العزري, ع�ئ�شة �شالح الدين abstract: Objectives: This study aimed to evaluate rates of success and perinatal complications of labour induction using an intracervical Foley catheter among women with a previous Caesarean delivery at a tertiary centre in Oman. Methods: This retrospective cohort study included 68 pregnant women with a history of a prev- ious Caesarean section who were admitted for induction via Foley catheter between January 2011 and December 2013 to the Sultan Qaboos University Hospital, Muscat, Oman. Patient data were collected from electronic and delivery ward records. Results: Most women were 25–35 years old (76.5%) and 20 women had had one previous vaginal delivery (29.4%). The most common indication for induction of labour was intrauterine growth restriction with oligohydramnios (27.9%). Most women delivered after 40 gestational weeks (48.5%) and there were no neonatal admissions or complications. The majority experienced no complications during the induction period (85.3%), although a few had vaginal bleeding (5.9%), intrapartum fever (4.4%), rupture of the membranes (2.9%) and cord prolapse shortly after insertion of the Foley catheter (1.5%). However, no cases of uterine rupture or scar dehiscence were noted. Overall, the success rate of vaginal birth after a previous Caesarean delivery was 69.1%, with the remaining patients undergoing an emergency Caesarean section (30.9%). Conclusion: The use of a Foley catheter in the induction of labour in women with a previous Caesarean delivery appears a safe option with a good success rate and few maternal and fetal complications. Keywords: Vaginal Birth after Cesarean; Induced Labor; Catheters; Pregnancy Complications; Oman. امللخ�ص: الهدف: تهدف هذه الدرا�شة اإىل تقييم معدلت النج�ح وم�ش�عف�ت فرتة م� حول الولدة لتحري�س املخ��س ب��شتخدام قثط�ر فويل داخل عنق الرحم بني الن�ش�ء اللواتي ولدن �ش�بق� بعملي�ت قي�رسية يف اأحد مراكز الرع�ية الث�لثية يف �شلطنة عم�ن. الطريقة: �شملت هذه الدرا�شة ال�شتع�دية لالتراب على 68 امراأة من اللواتي خ�شعن لعملي�ت قي�رسية يف ال�ش�بق و مت قبولهن للولدة املحر�شة عربا�شتخدام قثط�ر فويل داخل عنق الرحم بني ين�ير 2011 ودي�شمرب ع�م 2013 مب�شت�شفى ج�معة ال�شلط�ن ق�بو�س, م�شقط, عم�ن. النتائج: مت جمع بي�ن�ت املر�شى من �شجالت جن�ح الولدة. ك�نت معظم الن�ش�ء من الفئة العمرية 35-25 �شنة )%76.5( و 20 امراأة ك�ن له� ولدة طبيعية �ش�بقة )%29.4(. اإن املوؤ�رسات الأكرث �شيوع� لتحري�س املخ��س هو قلة وزن اجلنني مع قلة ال�ش�ئل ال�شلوي )%27.9(. متت الولدة يف معظم الن�ش�ء بعد 40 اأ�شبوع� من احلمل )%48.5( ومل تتواجد اي م�ش�عف�ت حلديثي الولدة. مل ت�شهد معظم احلوامل اأي م�ش�عف�ت خالل دور التحري�س )%85.3(, ولكن حدثت بع�س امل�ش�عف�ت يف عدد قليل وت�شمنت النزيف املهبلي )%5.9(, واحلمى اأثن�ء الولدة )%4.4(, ومتزق الأغ�شية )%2.9( وهبوط احلبل ال�رسي بعد فرتة وجيزة من اإدخ�ل قثط�ر فويل )%1.5(. ومع ذلك, مل يالحظ اأي ح�لت متزق الرحم اأو تفزر قي�رسية لعملي�ت املر�شى بقية خ�شوع مع ,69.1% ال�ش�بقة القي�رسية الولدة بعد الطبيعية الولدة جن�ح معدل ك�ن وعموم�, الندبة. ط�رئة )%30.9(. النتائج: اإن ا�شتخدام قثط�ر فويل يف حتري�س املخ��س يف الن�ش�ء ذوات الولدات القي�رسية ال�ش�بقة يبدو خي�را اآمن� مع ن�شبة جن�ح جيدة وم�ش�عف�ت قليلة لالأم واجلنني. الكلمات املفتاحية: الولدة املهبلية بعد القي�رسية؛ ولدة حمر�شة؛ قثط�ر؛ م�ش�عف�ت احلمل؛ عم�ن. Use of Intracervical Foley Catheter for Induction of Labour in Cases of Previous Caesarean Section Experience of a single tertiary centre in Oman Hazel Gonsalves,1 *Nihal Al-Riyami,1 Tamima Al-Dughaishi,1 Vaidayanathan Gowri,2 Mohammed Al-Azri,3 Ayesha Salahuddin1 clinical & basic research Sultan Qaboos University Med J, November 2016, Vol. 16, Iss. 4, pp. e445–450, Epub. 30 Nov 16 Submitted 8 Mar 16 Revision Req. 8 May 16; Revision Recd. 19 Jul 16 Accepted 2 Aug 16 doi: 10.18295/squmj.2016.16.04.007 Advances in Knowledge - To the best of the authors’ knowledge, this is the first time a study of this kind has been conducted in Oman. - Pregnant women who have previously undergone a Caesarean section are at risk of various complications during subsequent labour. The findings of this study indicate that the use of a Foley catheter for induction of labour may be a safe option for this population. Use of Intracervical Foley Catheter for Induction of Labour in Cases of Previous Caesarean Section Experience of a single tertiary centre in Oman e446 | SQU Medical Journal, November 2016, Volume 16, Issue 4 For subsequent pregnancies, women witha previous history of a Caesarean delivery may be offered either a trial of vaginal birth after Caesarean section (VBAC) or an elective repeat Caesarean section.1 The former option is well accepted as a practical and safe means of decreasing Caesarean delivery rates.2,3 Women who have previously delivered via Caesarean section have subsequent vaginal delivery rates of 50–85%.4 The induction of labour in women with a prior Caesarean delivery is more likely to result in a subsequent Caesarean delivery.5 In a prospective observational study of 11,778 women, induction of labour was associated with a significantly higher risk of unsuccessful VBAC (i.e. requiring an emergency Caesarean section) than spontaneous labour.6 In contrast, a previous history of vaginal delivery and a favourable cervical status were found to significantly increase chances of success.6 Uterine rupture is a major concern for women with a prior Caesarean section; a population-based retrospective cohort study found that the rate of uterine rupture following a previous Caesarean delivery was 1.6 per 1,000 women.7 Higher rates of rupture are associated with induced labour rather than spontaneous labour; other risk factors include an unfavourable cervix and the method of cervical ripen- ing used.5 The safest and most efficacious method of cervical ripening and/or induction of labour in women with previous Caesarean deliveries has not yet been established. Induction with oxytocin appears to have a lower risk of uterine rupture than prostaglandins.7 Although data regarding mechanical methods of cervical ripening in this population are limited by low sample sizes and the retrospective nature of the analyses, favourable outcomes have been reported.7 The advantages of a mechanical method include a decreased risk of uterine tachysystole and fetal distress, stability at room temperature and low cost.8 Several trials have presented evidence of the efficacy of the intracervical Foley catheter in comparison to prostaglandins for pre-induction cervical ripening.9,10 A meta-analysis of randomised trials comparing mechanical versus pharmacological methods showed mechanical devices to be associated with a lower risk of uterine hyperstimulation and fetal heart rate abnormalities.11 The guidelines of the Society of Obstetricians and Gynecologists of Canada state that “a Foley catheter may be safely used to ripen the cervix in a woman planning a trial of labour after Caesarean section”.4 In contrast, the American Congress of Obstetricians and Gynecologists believe that, given a lack of compelling data and the increased risk of mechanical dilatation, such interventions should only be an option for trial of VBAC delivery among candidates with an unfavour- able cervix.12 Therefore, the aim of the current study was to evaluate the safety and efficacy of induction of labour using an intracervical Foley catheter among pregnant women with a previous history of Caesarean delivery admitted to a tertiary centre in Oman. Methods This retrospective cohort study included 68 pregnant women with a previous history of Caesarean delivery who were admitted from January 2011 to December 2013 to the Sultan Qaboos University Hospital, Muscat, Oman, for labour induction via Foley cath- eter for a VBAC trial. Women who refused trial of labour, those who were induced via other methods (e.g. oxytocin administration or artificial rupture of the membranes) and patients with missing data were excluded from the study. Patient data were collected from the hospital information system and delivery ward records, including: age; parity; body mass index (BMI); a prior history of vaginal delivery; Bishop scores at the time of insertion and removal of the catheter; indications for the induction of labour; mode of delivery; and the duration of labour. Postnatal outcomes were also noted, including the gestational age at delivery, birth weight and Apgar scores of the baby and the presence of any neonatal complications. In all cases, a size 18 single balloon Foley catheter was used for induction of labour. The catheter was introduced under sterile conditions into the intracervical canal past the internal opening of the cervix and the bulb was inflated with 30–60 cm3 of water. The catheter was kept in place for 24 hours unless - Other centres in Oman use prostaglandins for the induction of labour in cases of previous Caesarean delivery. Further studies are required to compare modes of induction, success rates, complications and perinatal outcomes in order to inform delivery practices in Oman. Application to Patient Care - The results of this study may encourage obstetricians to use a Foley catheter as the main mode of induction of labour in patients who have previously had a Caesarean section. - Thorough patient assessment and counselling is critical before deciding on the mode of delivery, as this choice may affect perinatal outcomes and future pregnancies. Hazel Gonsalves, Nihal Al-Riyami, Tamima Al-Dughaishi, Vaidayanathan Gowri, Mohammed Al-Azri and Ayesha Salahuddin Clinical and Basic Research | e447 it fell out spontaneously beforehand. The primary outcome measure of the study was the success rate of VBAC while the secondary outcomes were perinatal complications such as uterine scar dehiscence, uterine rupture and perinatal mortality. Uterine rupture was defined as a disruption of the uterine muscle extending to and involving the uterine serosa or disruption of the uterine muscle with extension to the bladder or broad ligament, while uterine dehiscence was defined as disruption of the uterine muscle with intact uterine serosa.13 Factors affecting the success rate of VBAC, such as a previous normal vaginal delivery and Bishop scores, were also studied; the Bishop scoring system used included five determinants—dilatation, effacement, station, position and consistency.14 The Statistical Package for the Social Sciences (SPSS), Version 19 (IBM Corp., Chicago, Illinois, USA) was used for data entry and analysis. All data and field notes were first transcribed into the SPSS program. A P value of <0.050 was deemed to be statistically significant. Ethical approval of this study was granted by the Medical Research & Ethics Committee of the College of Medicine & Health Sciences at Sultan Qaboos University (MREC #562). All women opted for induction of labour with a Foley catheter after appropriate counselling and assessment by a senior obstetrician. Results A total of 68 women were included in the study. Most of the women were 25–35 years old (76.5%) and were primiparous (63.2%). Due to missing height records, BMI could only be calculated for 48 women; of these, 58.3% were obese and 27.1% were overweight. Only 20 women (29.4%) had had a previous vaginal delivery. Most women delivered after 40 gestational weeks (48.8%) [Table 1]. Table 1: Sociodemographic variables of pregnant women with a history of a previous Caesarean section admitted for induction via Foley catheter (N = 68) Variable n (%) Age in years <25 4 (5.9) 25–35 52 (76.5) >35 12 (17.6) BMI in kg/m2* 18.5–24.9 7 (14.6) 25.0–29.9 13 (27.1) ≥30.0 28 (58.3) Gravidity† Multigravida 56 (82.4) Grand multigravida 12 (17.6) Parity‡ Primiparous 43 (63.2) Multiparous 21 (30.9) Grand multiparous 2 (2.9) Great grand multiparous 2 (2.9) Previous vaginal delivery Yes 20 (29.4) No 48 (70.6) Gestational age at delivery in weeks <37 6 (8.8) 37–40 29 (42.6) >40 33 (48.5) *Total dataset for this variable was 48 due to missing data. †Women who had had two to four previous pregnancies were defined as multigravida while woman who had had five to six previous pregnancies were considered grand multigravida. ‡Women who had delivered one live infant were defined as primiparous, while those who had had delivered two to four live infants, five to six live infants and seven or more live infants were considered multiparous, grand multiparous and great grand multiparous, respectively. Table 2: Indications for labour induction and complications during induction among pregnant women with a history of a previous Caesarean section admitted for induction via Foley catheter (N = 68) n (%) Indication for labour induction Pregnancy duration of ≥40 gestational weeks 18 (26.5) IUGR with oligohydramnios 19 (27.9) IUFD 5 (7.4) GDM with polyhydramnios 12 (17.6) Poor BPP 5 (7.4) Uncontrolled epilepsy 2 (2.9) PIH 6 (8.8) Unknown 1 (1.5) Complication during induction None 58 (85.3) Rupture of membrane 2 (2.9) Fever 3 (4.4) Cord prolapse 1 (1.5) Vaginal bleeding 4 (5.9) IUGR = intrauterine growth restriction; IUFD = intrauterine fetal death; GDM = gestational diabetes mellitus; BPP = biophysical profile; PIH = pregnancy-induced hypertension. Use of Intracervical Foley Catheter for Induction of Labour in Cases of Previous Caesarean Section Experience of a single tertiary centre in Oman e448 | SQU Medical Journal, November 2016, Volume 16, Issue 4 Table 2 shows the various indications for induction of labour and the complications observed during the induction period. Labour was most commonly induced due to intrauterine growth restriction with oligohydramnios (27.9%). No complications were noted during the induction period in the majority of women (85.3%). There were no cases of uterine rupture or scar dehiscence. Three women had intrapartum fever which subsided postpartum without evidence of chorioamnionitis on placental histopathology. Four women experienced vaginal bleeding following the insertion of the Foley catheter; three had minimal bleeding and subsequently underwent a successful VBAC, but one had heavy vaginal bleeding and fetal bradycardia, resulting in an emergency Caesarean section. There was no evidence of placenta previa or abruptio in the latter case. One patient had an emergency Caesarean section 30 minutes after the insertion of the Foley catheter due to rupture of the membranes and cord prolapse; this 26-year-old gravida 2, para 1 woman had had a Caesarean section two years previously due to fetal distress. She underwent labour induction with a Foley catheter at 38 gestational weeks and four days due to gestational diabetes with polyhydramnios (amniotic fluid index = 263 mm). Her Bishop score before the insertion of the catheter was 2. All women went into labour when the catheter was removed; however, 46 women (67.6%) and 42 women (61.8%) required oxytocin and artificial rupture of the membranes, respectively, to augment labour. The overall success rate of VBAC was 69.1%, with 47 women successfully giving birth via vaginal delivery. For the remaining 21 women (30.9%), emergency Caesarean sections were performed due to failure to progress (n = 11; 52.4%), non-reassuring fetal status (n = 9; 42.9%) and cord prolapse (n = 1; 4.8%). Women with a successful VBAC had a mean duration of labour of 8.04 ± 4.57 hours (range: 3–25 hours) for stage one labour and 22.74 ± 27.00 minutes (range: 2–165 minutes) for stage two labour. There was a significant difference in mean maternal age between women who had a successful VBAC and those who underwent an emergency Caesarean section (P = 0.007). No significant differences were noted between the groups in terms of gestational age of delivery, Bishop scores at Foley’s insertion and removal, mean neonatal birth weights or Apgar scores at one and five minutes. There was a significant difference in mode of delivery between those who had had a previous vaginal delivery and those who had not (P = 0.019) [Table 3]. Table 4 shows the success rate of VBAC among patients who had had a previous vaginal delivery versus a previous Caesarean delivery in their earlier pregnancy. The VBAC success rate was 85.0% among those with a previous vaginal birth in comparison to 62.5% for those with a previous Caesarean section (P = 0.067). Table 3: Comparison of demographic, maternal and fetal variables between successful vaginal births versus emergency Caesarean section deliveries among pregnant women with a history of a previous Caesarean section admitted for induction via Foley catheter (N = 68) Variable Successful VBAC Emergency Caesarean section P value n (%) Mean ± SD n (%) Mean ± SD Age in years 47 (69.1) 29.62 ± 4.32 21 (30.9) 33.66 ± 5.27 0.007 BMI in kg/m2* 32 (66.7) 32.34 ± 8.13 16 (33.3) 31.09 ± 4.70 0.575 Gestational age at delivery in weeks 48 (70.6) 38.89 ± 2.73 20 (29.4) 38.86 ± 1.70 0.969 Bishop score at insertion 47 (69.1) 2.40 ± 0.54 21 (30.9) 2.19 ± 0.40 0.075 Bishop score at removal 47 (69.1) 4.40 ± 1.10 21 (30.9) 4.00 ± 1.18 0.175 Parity† 47 (69.1) 1.98 ± 1.51 21 (30.9) 1.62 ± 1.47 0.365 Previous vaginal delivery 47 (69.1) 0.51 ± 0.91 21 (30.9) 0.14 ± 0.36 0.019 Birth weight in kg 47 (69.1) 3.05 ± 0.65 21 (30.9) 3.16 ± 0.46 0.478 Apgar score at 1 minute‡ 44 (67.7) 8.36 ± 1.98 21 (32.3) 8.24 ± 1.30 0.792 Apgar score at 5 minutes‡ 44 (67.7) 9.43 ± 2.12 21 (32.3) 9.71 ± 0.64 0.553 VBAC = vaginal birth after Caesarean section; SD = standard deviation; BMI = body mass index. *Total dataset for this variable was 48 due to missing data. †Women who had delivered one live infant were defined as primiparous, while those who had had delivered two to four live infants, five to six live infants and seven or more live infants were considered multiparous, grand multiparous and great grand multiparous, respectively. ‡Total dataset for this variable was 65 due to missing Apgar data for three neonates. Hazel Gonsalves, Nihal Al-Riyami, Tamima Al-Dughaishi, Vaidayanathan Gowri, Mohammed Al-Azri and Ayesha Salahuddin Clinical and Basic Research | e449 Discussion Among the various predictors for a successful VBAC, a previous vaginal birth is the most promising, yielding a success rate of 87–90%.15,16 Other factors, such as induced labour or increased BMI, may reduce the success rate to 40%.17 According to previous research, the overall success rate of VBAC is 72–76%.18–20 Few studies have looked into the success rate of VBAC following induction of labour via Foley catheter. One recent study included 208 women with a previous history of Caesarean delivery who were induced using a Foley catheter; the success rate was 71%, with two perinatal deaths (1.0%), one of which was due to uterine rupture (0.5%).21 In the current study, the success rate of VBAC was 69.1% with no cases of uterine rupture or perinatal death. All women who have previously undergone a Caesarean delivery should be counselled appropriately and offered both VBAC and an elective repeat Caesarean section as options for trial of labour. The risks and benefits of both approaches should be explained, including associated perinatal morbidity and mortality rates. Women who opt for a VBAC should be thoroughly assessed so as to better predict the chances of success with this method. Maternal age, BMI, Bishop score at Foley insertion and removal, gestational age at delivery, birth weight and previous vaginal births were examined as predictors for successful VBAC in the present study. However, the only statistically significant differences noted were with maternal age and a previous vaginal birth. Patients who had a better Bishop score at insertion of the Foley catheter had slightly higher success rates for VBAC, but this association was not statistically significant. This could be attributed to the small sample size of the current study. In a case- control study of 101 successful VBAC cases and 103 unsuccessful controls at three major hospitals, Birara et al. found that a previous history of successful VBAC and cervical dilatation of more than 3 cm at Table 4: Comparison of delivery modes between those with a previous vaginal versus Caesarean section delivery in earlier pregnancy among pregnant women with a history of a previous Caesarean section admitted for induction via Foley catheter (N = 68) Previous method of delivery n (%) P value Emergency Caesarean VBAC Total Caesarean 18 (37.5) 30 (62.5) 48 (100.0) 0.067 Vaginal 3 (15.0) 17 (85.0) 20 (100.0) Total 21 (30.9) 47 (69.7) 68 (100.0) VBAC = vaginal birth after Caesarean section. admission were the best predictors for successful VBAC.22 Srinivas et al. similarly investigated predict- ors of failed VBAC among 13,706 women; gestational age at delivery, maternal age, maternal race, labour type (spontaneous versus induced), lack of a prior vaginal delivery and cephalopelvic disproportion or failed induction as the prior Caesarean section indication were significantly associated with VBAC failure (failure rate: 24.5%).23 Having a prior vaginal delivery was the factor most indicative of a successful VBAC attempt (odds ratio: 0.21, 95% confidence interval: 0.19–0.24) and labour induction had the highest association with VBAC failure.23 Yokoi et al. also concluded that the best predictor for a successful VBAC was a previous VBAC in their study of 664 women with one previous Caesarean delivery.24 To the best of the authors’ knowledge, this study is the first of its kind to be conducted in Oman. The Sultan Qaboos University Hospital was one of the first centres in Oman to induce labour using a Foley catheter in cases of previous Caesarean delivery; the majority of other centres in Oman use prostaglandins for the induction of labour. To this end, further research is necessary to compare success rates and complications of VBAC in patients induced with prostaglandins versus a Foley catheter. The current study was limited by its small sample size and retrospective nature. It is recommended that future prospective studies utilise a multicentre approach with a larger number of patients. Conclusion Induction of labour via Foley catheter in women who have previously undergone a Caesarean section delivery appears to be a safe option with a good success rate and few complications for both mother and fetus. c o n f l i c t o f i n t e r e s t The authors declare no conflicts of interest. f u n d i n g No funding was received for this study. References 1. Royal College of Obstetricians and Gynaecologists. Birth after previous Caesarean birth: Green-top guideline no. 45. From: www.rcog.org.uk/globalassets/documents/guidelines/gtg_45. pdf Accessed: Jul 2016. 2. National Institutes of Health. NIH consensus developed conference statement on vaginal birth after cesarean: New insights. From: www.consensus.nih.gov/2010/images/vbac/ vbac_statement.pdf Accessed: Jul 2016. 3. American College of Obstetricians and Gynecologists. ACOG practice bulletin no. 115: Vaginal birth after previous cesarean delivery. Obstet Gynecol 2010; 116:450–63. doi: 10.1097/AOG. 0b013e3181eeb251. 4. Martel MJ, MacKinnon CJ; Clinical Practice Obstetrics Committee, Society of Obstetricians and Gynaecologists of Canada. Guidelines for vaginal birth after previous Caesarean birth. J Obstet Gynaecol Can 2005; 27:164–88. 5. Biswas A. Management of previous cesarean section. Curr Opin Obstet Gynecol 2003; 15:123–9. 6. Grobman WA, Gilbert S, Landon MB, Spong CY, Leveno KJ, Rouse DJ, et al. Outcomes of induction of labour after one prior caesarean. Obstet Gynecol 2007; 109:262–9. doi: 10.1097/01. AOG.0000254169.49346.e9. 7. Lydon-Rochelle M, Holt VL, Easterling TR, Martin DP. Risk of uterine rupture during labor among women with a prior cesarean delivery. N Engl J Med 2001; 345:3–8. doi: 10.1056/ NEJM200107053450101. 8. Bujold E, Blackwell SC, Gauthier RJ. Cervical ripening with transcervical foley catheter and the risk of uterine rupture. Obstet Gynecol 2004; 103:18–23. doi: 10.1097/01. AOG.0000109148.23082.C1. 9. Dalui R, Suri V, Ray P, Gupta I. Comparison of extraamniotic Foley catheter and intracervical prostaglandin E gel for preinduction cervical ripening. Acta Obstet Gynecol Scand 2005; 84:362–7. doi: 10.1111/j.0001-6349.2005.00662.x. 10. Prager M, Eneroth-Grimfors E, Edlund M, Marions L. A randomised controlled trial of intravaginal dinoprostone, intravaginal misoprostol and transcervical balloon catheter for labour induction. BJOG 2008; 115:1443–50. doi: 10.1111/j. 1471-0528.2008.01843.x. 11. Boulvain M, Kelly A, Lohse C, Stan C, Irion O. Mechanical methods for induction of labour. Cochrane Database Syst Rev 2001; 4:CD001233. doi: 10.1002/14651858.CD001233. 12. American College of Obstetricians and Gynecologists Committee on Obstetric Practice. ACOG Practice Bulletin #54: Vaginal birth after previous Caesarean. Obstet Gynecol 2004; 104:203–12. doi: 10.1097/00006250-200407000-00060. 13. Landon MB, Hauth JC, Leveno KJ, Spong CY, Leindecker S, Varner MW, et al. Maternal and perinatal outcomes associated with a trial of labor after prior cesarean delivery. N Engl J Med 2004; 351:2581–9. doi: 10.1056/NEJMoa040405. 14. Bishop EH. Pelvic scoring for elective induction. Obstet Gynecol 1964; 24:266–8. 15. Smith GC, White IR, Pell JP, Dobbie R. Predicting caesarean section and uterine rupture among women attempting vaginal birth after prior cesarean section. PLoS Med 2005; 2:e252. doi: 10.1371/journal.pmed.0020252. 16. Gyamfi C, Juhasz G, Gyamfi P, Stone JL. Increased success of trial of labor after previous vaginal birth after cesarean. Obstet Gynecol 2004; 104:715–19. doi: 10.1097/01.AOG.00 00139516.43748.1b. 17. Landon MB, Leindecker S, Spong CY, Hauth JC, Bloom S, Varner MW, et al. The MFMU Cesarean Registry: Factors affecting the success of trial of labor after previous cesarean delivery. Am J Obstet Gynecol 2005; 193:1016–23. doi: 10.1016/j.ajog.2005.05.066. 18. Guise JM, Berlin M, McDonagh M, Osterweil P, Chan B, Helfand M. Safety of vaginal birth after cesarean: A systematic review. Obstet Gynecol 2004; 103:420–9. doi: 10.1097/01. AOG.0000116259.41678.f1. 19. Wen SW, Rusen ID, Walker M, Liston R, Kramer MS, Baskett T, et al. Comparison of maternal mortality and morbidity between trial of labor and elective cesarean section among women with previous cesarean delivery. Am J Obstet Gynecol 2004; 191:1263–9. doi: 10.1016/j.ajog.2004.03.022. 20. Chauhan SP, Martin JN Jr, Henrichs CE, Morrison JC, Magann EF. Maternal and perinatal complications with uterine rupture in 142,075 patients who attempted vaginal birth after cesarean delivery: A review of the literature. Am J Obstet Gynecol 2003; 189:408–17. doi: 10.1067/S0002-9378(03)00675-6. 21. Jozwiak M, van de Lest HA, Burger NB, Dijksterhuis MG, De Leeuw JW. Cervical ripening with Foley catheter for induction of labor after cesarean section: A cohort study. Acta Obstet Gynecol Scand 2014; 93:296–301. doi: 10.1111/ aogs.12320. 22. Birara M, Gebrehiwot Y. Factors associated with success of vaginal birth after one caesarean section (VBAC) at three teaching hospitals in Addis Ababa, Ethiopia: A case control study. BMC Pregnancy Childbirth 2013; 13:31. doi: 10.1186/1471-2393-13-31. 23. Srinivas SK, Stamilio DM, Stevens EJ, Odibo AO, Peipert JF, Macones GA. Predicting failure of a vaginal birth attempt after cesarean delivery. Obstet Gynecol 2007; 109:800–5. doi: 10.1097/01.AOG.0000259313.46842.71. 24. Yokoi A, Ishikawa K, Miyazaki K, Yoshida K, Furuhashi M, Tamakoshi K. Validation of the prediction model for success of vaginal birth after cesarean delivery in Japanese women. Int J Med Sci 2012; 9:488–91. doi: 10.7150/ijms.4682. Use of Intracervical Foley Catheter for Induction of Labour in Cases of Previous Caesarean Section Experience of a single tertiary centre in Oman 450 | SQU Medical Journal, November 2016, Volume 16, Issue 4