|Year : 2014 | Volume
| Issue : 1 | Page : 29-33
Induction of labor in patients with previous cesarean section with unfavorable cervix
Laishram Trinity Meetei1, Vanita Suri2, Neelam Aggarwal2
1 Department of Obstetrics and Gynaecology, Regional Institute of Medical Sciences, Imphal, Manipur, India
2 Department of Obstetrics and Gynaecology, Post Graduate Institute of Medical Education and Research, Chandigarh, India
|Date of Web Publication||24-Jun-2014|
Dr. Laishram Trinity Meetei
Department of Obstetrics and Gynaecology, Regional Institute of Medical Sciences, Imphal - 795 004, Manipur
Source of Support: None, Conflict of Interest: None
Background and Objective: Due to increased risk of uterine rupture with prostaglandins in previous cesarean patients, its use has been discouraged as ripening agent in previous cesarean patients. This study was conducted to compare the efficacy and safety of Foley catheter with low dose oxytocin as cervical ripening agent in women with previous cesarean section (CS). Materials and Methods: This was prospective randomized study, including 60 women (30 in each group) with previous CS with unfavorable cervix who needs induction of labor after 28 weeks. Outcomes were analyzed in terms of change in Bishop score (BS), route of delivery and complications. Results: The BS before and after ripening between the two groups was similar (P > 0.05). However, the change in BS within each group was 3.07 and 3.30 in Foley and oxytocin group respectively and this was statistically significant (P < 0.001). Twenty (66.7%) patients in Foley group had a vaginal delivery and 18 (60%) in oxytocin group did so. There were two cases of scar dehiscence in oxytocin group and non in Foley group. Conclusion: Both Foley and low dose oxytocin are good cervical ripening agents in previous cesarean patients. However, the two cases of scar dehiscence in low dose oxytocin group is a concern of safety.
Keywords: Cervical ripening agents, Previous cesarean, Unfavorable cervix
|How to cite this article:|
Meetei LT, Suri V, Aggarwal N. Induction of labor in patients with previous cesarean section with unfavorable cervix. J Med Soc 2014;28:29-33
|How to cite this URL:|
Meetei LT, Suri V, Aggarwal N. Induction of labor in patients with previous cesarean section with unfavorable cervix. J Med Soc [serial online] 2014 [cited 2020 Oct 20];28:29-33. Available from: https://www.jmedsoc.org/text.asp?2014/28/1/29/135223
| Introduction|| |
The purpose of cervical ripening and induction of labor is to achieve vaginal delivery and to avoid operative delivery by cesarean section (CS).  The present day overall increase in CS is partly due to repeat CS and a trial of labor after previous CS has been accepted as a way to decrease the overall cesarean delivery rate. Elective induction was safe and uniformly successful when Bishop score was 9 or more.  Failed induction is the most important risk of oxytocin induction in labor, and it is strongly related to the degree of ripeness of cervix.  Cervical ripening in previous cesarean patients undergoing induction of labor with unfavorable cervix is safe has been shown in various studies. , Due to increased risk of uterine rupture, use of prostaglandins for cervical ripening and induction of labor in women attempting vaginal birth after cesarean is discouraged by the American College of Obstetricians and Gynecologists (ACOG).  Foley catheter has been studied as cervical ripening agent in previous cesarean patients. ,, Low dose oxytocin has been studied as cervical ripening agent in unscarred uterus only. , The uterine rupture rate with Foley varies from 0.45% to 1.6%. However, most of studies have not mentioned the details of cervical status or Bishop score (BS) before and after ripening. The purpose of this study was to compare the efficacy and safety of Foley catheter with low dose oxytocin as cervical ripening agent in women with previous CS.
| Materials and Methods|| |
During the period between July 2004 and November 2005, 60 women with previous CS with unfavorable cervix admitted for induction of labor were included. This prospective randomized study was conducted in the Department of Obstetrics and Gynecology, PGIMER, Chandigarh. Randomization was done using tippet's table. Patients with one previous low transverse CS, singleton live pregnancy with cephalic presentation, period of gestation (POG) >28 weeks and BS <5 were included in the study. Exclusion criteria were previous classical or T-shaped incision, unknown scar, transfundal uterine surgery, medical or obstetric complications that preclude vaginal delivery, placenta previa, low lying placenta, undiagnosed vaginal bleeding, maternal heart disease, premature/preterm premature rupture of membranes, interval between previous CS and present pregnancy/conception <6 months, cervicovaginal infection, history of (h/o) unclean vaginal examination and h/o infection in previous CS.
After emptying the bladder the patients were placed in dorsal supine position, Sim's speculum was introduced, cervix was cleaned, and anterior lip of the cervix was held with sponge holding forceps and sterile 16 Fr Foley catheter was introduced into the endocervical canal. It was inflated with 30 ml normal saline and made taught against internal os. Patients were then observed for 12 h, then BS was rechecked or earlier if Foley expelled before 12 h. In the absence of active labor, oxytocin induction was started at a dose of 1 mU/min and escalating doses of oxytocin, doubled every half an hour was given (2 mU/min, 4 mU/min, 8 mU/min…). The intravenous (IV) oxytocin doses was titrated against the response till the patients got good contractions lasting 40 s with frequency of 3 contractions/10 min. IV oxytocin was not increased beyond 32 mU/min. Amniotomy was done as and when indicated.
Subjects were given IV oxytocin 1 mU/min and increased to 2 mU/min after 1 h if no contraction frequency of ≥3/10 min was recorded and 4 mU/min if no similar conditions were met, and it was maintained for the next 10 h barring fetal intolerance. After 12 h, BS was rechecked, and oxytocin for induction or augmentation was increased as in the Foley group up to a maximum of 32 mU/min.
The outcome was analyzed in terms of change in BS before and after 12 h of ripening, percentage and time interval of patients entering spontaneous labor, insertion and expulsion interval of Foley catheter, route of delivery/outcome of delivery, time required from the beginning of cervical ripening to delivery (preparation-delivery interval [PDI]) and side-effects and complications (hyperstimulation, fetal distress, scar dehiscence, uterine rupture, etc.).
Statistical analysis was performed using Student's unpaired t-test, Chi-square test, and Mann - Whitney U-test. P < 0.05 was considered as significant.
| Results|| |
The patients characteristics such as age, parity, POG, number of vaginal deliveries, and interpregnancy interval (IPI) were comparable in both groups. Majority of the subjects belonged to 24-29 years of age. Majority are primiparas, 86.7% and 80% in Foley and oxytocin group respectively. Maximum number of subjects was between the 38 and 40 weeks. Four (13.3%) in Foley group and 6 (20%) in oxytocin group had prior vaginal delivery. IPI (delivery to conception) was similar in both groups. In both groups, 63.3% had IPI more than 24 months.
[Table 1] shows the various indications of induction of labor. Oligohydramnios being the commonest, followed by postdated pregnancy and pregnancy induced hypertension.
To know the efficacy, BS at 0 h, 12 h and change in BS were compared between the two groups and is summarized in [Table 2]. Two in Foley group and three in oxytocin group delivered during ripening. The BS at 0 h, 12 h and change in BS were comparable between the two groups, but the change in BS within the group was statistically significant (P < 0.001).
Labor characteristics of the patients are shown in [Table 3]. In Foley group, 16.7% and 30% in oxytocin group had labor during ripening. The median dose of oxytocin used was 25.16 U and 21.37 U in Foley and oxytocin group, respectively. The vaginal delivery rate was 66.7% and 60% in Foley and oxytocin group, respectively. All these findings were statistically comparable.
The PDI is shown in [Table 4]. Majority in oxytocin group delivered within 24 h and in Foley group after 24 h. This was statistically significant (P < 0.05), but the mean preparation-delivery was comparable.
The complications in the present study are shown in [Table 5]. Even though the individual characteristics were comparable, complications were more in oxytocin group.
The neonatal outcome in the form of Apgar score at 1 and 5 min, birth weight, neonatal jaundice and admission to nursery were comparable in both groups as shown in [Table 6].
| Discussion|| |
This study was conducted with the aim of comparing the efficacy and safety of extraamniotic Foley catheter with low dose oxytocin as cervical ripening agents in patients with previous CS. The characteristics of the subjects in both groups were comparable in relation to age, parity and POG. The majority in both groups were between 25 and 29 years, comprising 36.6% in Foley group and 43.3% in oxytocin group, mean being 28.41 and 28 years respectively. Majority were primiparas, 86.7% and 80% in Foley and oxytocin group respectively. Maximum number of subjects were between 38 and 40 weeks POG, mean being 37 weeks and 38.9 weeks in Foley and oxytocin group, respectively. In the study by Lydon-Rochelle et al.,  majority were between 25 and 29 years, and POG was between 38-42 weeks. In Bujold's study,  the mean age in Foley group was 31.1 years. A mean age of 26.6 years and POG of 39.6 weeks, respectively was reported by Del Valle et al. 
In this study, the IPI was 41.27 months and 39.57 months in Foley and oxytocin groups, respectively. The most common indication for induction of labor was oligohydramnios followed by postdatism and pregnancy induced hypertension. Lydon-Rochelle  reported IPI of 25-36 months and hypertensive disorders of pregnancy as the most common indication. In Bujold's study  postdatism was the commonest indication for induction of labor. In this study, the mean BS at 0 h and 12 h in Foley group was 2.53 and 5.54 and in oxytocin group 3.1 and 6.37. Both were comparable, but the change in BS from 0 to 12 h within each group was statistically significant (P < 0.05).
The mean change in BS with Foley as cervical ripening agent in unscarred uterus ranged from 3 to 3.5. ,, Khotaba et al.  found a change in BS of 5.4 and 3.4 in those who delivered vaginally within 30 h and after 30 h and 2.2 in those who had CS respectively. Pollnow and Broekhuizen  found a mean BS of 4 and 6.4 before and after ripening with low dose oxytocin. These findings (change in BS) were comparable with the present study.
The mean time taken for spontaneous expulsion of Foley reported by Dalui et al.  was 7.98 h. Others have reported a mean time of 10 h. , In this study 7/30 (23.3%) had spontaneous expulsion of Foley and the mean time taken was 7.35 h. St Onge and Connors  have reported that 35.5% subjects had labor during ripening. In this study, 16% and 30% in Foley and oxytocin group, respectively had labor during ripening. Among these, two subjects in Foley and three subjects in oxytocin group delivered during ripening phase.
Oxytocin was used in 26/30 subjects in Foley group, two delivered during ripening, and another two did not require oxytocin. The oxytocin requirement was 25.16 U and 21.37 U in Foley and oxytocin group, respectively. In unscarred uterus using Foley, the oxytocin requirement was 9 U and 7.76 U as reported by Dalui et al.  and Surita et al. 
The PDI in unscarred uterus ranged from 10.9 to 27.09 h. ,, The earlier studies in scarred uterus had not mentioned the PDI. In this study, the PDI was 27.54 h and 22.88 h for Foley and oxytocin group, respectively. In a study using low dose oxytocin in unscarred uterus by Ferguson et al.,  the PDI was 27 h.
Majority (66.67%) in oxytocin group delivered within 24 h, but only 30% in Foley group. However, 93.3% and 86.7% delivered within 36 h in Foley and oxytocin group, respectively which is better than that of Jackson et al.  where only 75% delivered within 36 h.
The vaginal delivery rate with Foley in unscarred and scarred uterus ranged from 57.4% to 89.4% ,, and 55.7% to 64.7%. ,, With low dose oxytocin the vaginal delivery was 66% and 74.7%. , There is no literature/study of low dose oxytocin as cervical ripening agent in previous CS. This study has a vaginal delivery rate of 66.7% and 60% in Foley and oxytocin group, respectively.
There were 10 (33.3%) and 12 (40%) subjects who had CS in Foley and oxytocin respectively. The most common indication being nonprogress of labor in Foley group and fetal distress in oxytocin group. Others indication being cervical dystocia, scar dehiscence and deep transverse arrest. This difference was not statistically significant.
Ravasia et al.  and Bujold et al.  have reported incidence of scar rupture of 0.8% and 1.6%, respectively with Foley in the previous section. No incidence of scar dehiscence/rupture was seen in the Foley group in the present study as in the case of Ben-Aroya et al.  and Khotaba et al.  However, there were two case of scar dehiscence in the oxytocin group during the latter part of the study. However, there were no fetal or maternal morbidity. The first case was G4P1021, induced at 40 weeks for poor biophysical profile. Her first cesarean was for nonprogress of labor and her IPI was 47 months her BS was 3 and 6 respectively, and she was operated for suspected scar dehiscence. The second case was G2P1001 at 39 weeks with gestational diabetes mellitus, induced for planned delivery. Her first cesarean was for fetal distress. However, she was operated for failed induction.
Horenstein and Phelan  have reported 3% scar dehiscence when oxytocin was used for induction of labor. Chez  has reported 0.3% and 0.5% scar dehiscence and rupture when oxytocin was used for induction. Rageth et al.  and Sanchez-Ramos et al.  have reported 0.65% and 0.85% incidence of scar rupture respectively with oxytocin in previous cesarean. One subject in oxytocin group had vaginal bleeding after 6 h of ripening, there was no evidence of abruption she had CS after 13 h of artificial rupture of membranes due to fetal bradycardia. One case of hypertonus, one atonic postpartum hemorrhage and one wound infection occurred in the Foley group. One cervical tear, one urinary retention and two cases of fever occurred in the oxytocin group. Febrile morbidity and vaginal bleeding was also reported by James et al.  and Embrey and Mollison.  James et al.  have reported nine cases of fever of which seven had a urinary tract infection.
| Conclusion|| |
This study concludes that both Foley and low dose oxytocin are good cervical ripening agents in patients with previous CS undergoing induction of labor with unfavorable cervix. Both achieved a vaginal delivery rate comparable with earlier studies. However, the two cases of scar dehiscence in low dose oxytocin group is a concern of safety. On the other hand, Foley has once again proved to be an effective as well as safe cervical ripening agent in patients with previous cesarean deliveries. The present study is too small to draw a final conclusion about the use of Foley in previous cesarean deliveries. Larger studies are needed to confirm this issue after selecting the subjects who fulfill the criteria laid down by ACOG. 
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[Table 1], [Table 2], [Table 3], [Table 4], [Table 5], [Table 6]
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