![[BHJ LOGO]](../../images/sp_bhjpan.gif) |
       |
|
|
PREINDUCTION CERVICAL RIPENING, AN EASIER AND SAFER ALTERNATIVE — A Randomised Study
Poornima R Ranka*, Alka S Gupta**,Shashank V Parulekar***
*Ex. Registrar; **Associate Prof.; ***Prof.; Dept. of Obstetrics and Gynaecology Seth GS Medical College, KEM Hospital, Parel, Mumbai - 400 012.
Hundred patients, both low risk and high risk were subjected to preinduction cervical ripening with either Foley’s catheter or dinoprostone gel. A prospective randomised comparative study was carried out to find out the success rate, side effects of both and maternal and perinatal outcomeINTRODUCTION
The goal of obstetrics is a pregnancy that results in a healthy infant and a healthy minimally traumatized mother. Much of the art of good obstetric care involves the delicate balance of avoiding caesarean delivery with all its attendant complications.
Planned pre induction cervical ripening and induction of labour has become an established part of modern obstetric practice.
One of the factors that influences successful induction of labour is the state of the uterine cervix. If the cervix is unripe (closed, uneffaced and firm,) Bishop’s cervical score less than 6, then the conventional method of induction of labour by surgical amniotomy is technically difficult and titration with intravenous oxytocin results in prolonged labour with risks of maternal and foetal complications and unsuccessful inductions, unnecessarily increasing the rates of caesarean section.
MATERIAL AND METHODS
Foley’s catheter No-20-F was used to ripen the cervix prior to Induction of Labour in 50 women and the results were compared with those obtainedusing 0.5 mg of dinoprostone PGE2 gel in another 50 women. Preinduction cervical scoring was noted. After 6 hours change in Bishop’s score was noted in both groups. The cervical dilatation and improvement in Bishop’s cervical score and outcome of induction of labour were compared in both the groups.
The protocol followed was as follows :
1.Time for score greater than 6 was noted and if the score still was less than 6, then in cases of Foley’s insertion, PGE2 gel was instilled and in cases of PGE2 gel, reinstillation done after a period of 6 hours.
2.If score was more than 6 then all patients (of both groups) were subjected to artificial surgical amniotomy of the forewaters, followed by titrated oxytocin drip at rate of 1 mu/min and then increased by algebraic progression.
3.The course of labour was charted on a partogram in every case.
This prospective study was conducted in a teaching hospital in the Dept of obstetrics and gynecology over a period of 1 year from June 1997 - June 1998.
Indications for cervical ripening and induction of labour were :
- Post term pregnancy
- Pregnancy induced hypertension / Toxaemia of pregnancy
- Oligohydramnios
- Intrauterine growth retardation
- Suspected foetal jeopardy
- Suspected placental insufficiency
- Premature rupture of membranes
- Previous LSCS with another indication for induction of labour.
- Bad obstetric history
- Diabetes mellitus.
In cases of PROM, dinoprostone gel used, as Foley’s catheter can not be used however in cases of systemic illnesses like bronchial asthma and in cases of previous LSCS or previously scarred uteri, Foley’s catheter was used, as PGE2 was contraindicated.
All patients were given antibiotic prophylaxis
Patient selection criteria were :
- Indication for induction of labour as mentioned above and a cervical score of less than 6.
- Singleton pregnancy
- Age group of 18 years or more
- Completed 37 weeks of pregnancy, as confirmed by menstrual dates, early clinical examination and sonography.
- No contraindications for vaginal delivery like, contracted pelvis, soft tissue tumours
- Primigravidas and multigravidas
- Patients with PROM
- Patients with one previous LSCS
- Multiple pregnancy, nonvertex presentations, placenta previa were excluded from the study.
Prior consent for cervical ripening and induction of labour after a detailed explanation was taken. All patients were evaluated.
Out of the total 100 patients studied, 50 had Foley’s insertion, No-20-F catheter with 30 cc saline in the bulb (Group A) and 50 had PGE2 gel instillation. These patients were admitted for induction of labour due to various indications described above. Under aseptic conditions and with patients in the lithotomy position, cervix was assessed on the Bishop’s scoring scale.
In group A, cervical os was exposed with a bivalve speculum and Foley’s catheter no - 20 was inserted into the extraamniotic space and bulb was inflated with 30 ml of normal saline, the distended bulb was hitched on the internal os and catheter was strapped to the abdomen for 6 hours. Antibiotic prophylaxis was given.
After 6 hours, catheters were either removed by deflation of bulb, or were expelled spontaneously. Bishop’s cervical scoring was again repeated and if score was more than 6, surgical forewater amniotomy was done for colour of liquor, followed by induction of labour and augmentation with oxytocin at 1 mu/min with titration, if liquor was clear.
In group B 0.5 mg dinoprostone PGE2 gel was instilled intracervically by the withdrawal technique aseptically, patient lied recumbent for 30 minutes, repeat per vaginum examination was done later after 6 hours, improvement in Bishop’s score more than 6 was noted, followed by surgical amniotomy and oxytocin augmentation.
Foetal heart rate and uterine activity were monitored strictly and half hourly intrapartum monitoring of foetal rate on CTG machine and progress of labour on partogram recorded in all cases.
RESULTS AND ANALYSIS
1. Patients characteristics Parity
Total No.
Foley’s catheter
PGE2
Primi
52
26
26
Multi
48
24
24
2. Indication for cervical ripening and induction of labour Indication Foley’s catheter PGE2 Postdatism 12 12 PIH/HT in preg 24 22 PROM 0 8 Prev LSCS 8 0 Others (IUGR) etc. 6 8 Commonest indication was pregnancy induced hypertension followed by prolonged pregnancy in both groups, however Foley’s catheter was used in previous LSCS and PGE2 in PROM.
Thus out of the total 52 primigravidas improvement in Bishop’s score after 6 hours was almost similar in both Foley’s catheter and PGE2 gel. And out of total 48 multigravidas, improvements in Bishops score was more in Foley’s catheter group (50% in PGE2 as compared to 75% in Foley’s catheter).
The analysis of mean duration of labour showed that there was no statistical significant difference between these two groups.
Two babies had an apgar score 4/10 at end of 1 min and 7/10 at end of 5 min in PGE2 groups whereas all babies in Foley’s catheter group had an apgar score of 9/10.
7. Indications for LSCS
3. Bishops scoring scale and change in Bishop score
Parity Method of cervical ripening Total No. Score > 6 hrs 6-9 10-13 Primis Foley’s catheter PGE2 26 10 (38.5%) 16 (61.54%) 26 11 (42.3%) 15 (57.7%)
Multis Foley’s catheter
PGE224 6 (25%) 18 (75%)
24 12 (50%) 12 (50%)
4. Mean duration of labour Parity
Method
Stage-I
II
III
Augmentation - delivery interval
Primi (26)
Foley’s
8 hr
25 min
10 min
8 hr-35 min
PGE2
6 hr
30 min
15 min
6 hr - 45 min Multis (24)
Foley’s
7 hr
20 min
6 min
7 hr - 26 min
PGE2
6 hr
18 min
6 min
6 hr - 24 min
5. Mode of delivery Mode of delivery Foley’s catheter PGE2 Normal vaginal delivery 40 39 Forceps 6 2 Vacuum Nil 1 LSCS 4 8
6. Apgar score Apgar at 1 min Score Foley’s catheter PGE2 At 5 min 4-6 Nil 2 7-8 Nil Nil 9-10 50 48 4-6 Nil Nil 7-8 Nil 2 9-10 50 48
7.Indications for LSCS Meconium
Nil
4
Foetal distress
Nil
4(non reassuring FHR)
Nonprogress of labour
4
Nil
Uterine hyperfunction
Nil
2
There were 4 cases of non progress of labour in Foley’s catheter group, however 4 cases of meconium, 4 cases of foetal distress and 2 of uterine hyperfunction in the PGE2 group. There was no increased incidence of neonatal sepsis or chorioamniotis or pueperal sepsis in any of our patients. There was no accidental rupture of membranes while introducing Foley’s catheter. No perinatal morbidity or mortality or maternal complications were noted.
8. Side effects Side effects
Foley’s catheter
PGE2
Nausea
Nil
24
Vomiting
Nil
30
Diarrhoea
Nil
32
Accidental rupture
Nil
Nil
Chorio amniotis
Nil
Nil
Hypertonicity
Nil
7
DISCUSSION
The secret of success of induction of labour lies in replicating as closely as possible the process of spontaneous parturition.
Cervical ripening is a normal preclude to the onset of myometrial contractions; It is important to choose a method which will ripen the cervix and have a successful outcome of planned induction of labour.
In our study, both Foley and PGE2 gel have been equally effective in primi gravidas in achieving cervical ripening and improving Bishop’s score1 and promoting changes resembling physiological events of ripening and labour, however in cases of multigravidas, Foley’s catheter have been superior (75%) as compared to PGE2 (50%).
Though intra cervical institution of PGE2, however in "Mother’s assessment of technique" showed a striking preference, for it was felt more natural as compared to intracervical Foley’s catheter. In today’s expensive world, Foley’s catheter which is half the price of dinoprostone gel is definitely a safer and cheaper alternative.
Foley’s catheter can also be used in cases of
1.Bronchial asthma
2.Increased intra ocular pressure
3.Previous LSCS
Foley’s catheter thus provides a better alternative.
In our study of 100 patients, in Group A of 50 women, Foley’s catheter was used and in Group B dinoprostone gel was used. We have analysed the mean duration of labour, the success rate of both groups, perinatal outcome in the form of Apgars, and NICU admission and complications.
We found that average mean duration of labour for both groups were almost similar and there was no statistical significant difference between the two groups.
In a randomised study by M. Ezimokhai and JN Nwabinelli2 (Dept. of Obs and Gyn, New Castle General Hosp April 1980) for induction of labour, comparative study was done between Foley’s catheter and dinoprostone 5 mg gel. The improvements in cervical score and outcome of induction of labour were similar in both groups. Similar outcome is seen in our study.
In another study by Jack Atad (Dept. of Obs and Gyn Carmel Medical Centre, Haifa Israel 1997) and Mordechaihallak MD (Wayne State University School of Medicine, Michigan, USA) a ripening and dilatation of unfavourable cervices for induction of labour by a double balloon device was done on 250 cases and the results showed significant ripening and dilatation of unfavourable cervices LSCS rate were also low.
Foley’s catheter has been used to ripen the cervix prior to surgical induction of labour [4] but the improvement was not quantitatively assessed. The main argument against the use of Foley’s catheter has been a risk of introduction of infection with accidental rupture of foetal membranes. In our study, no such accidental rupture has occurred.
Foley’s catheter acts as a mechanical dilator and improves dilatation rather than effacement of the cervix, whereas PGE2, acts by softening andincreasing the effacement of the cervix rather than dilatation. For successful Foley’s catheter induction immediate amniotomy followed by titrated oxytocin drip is needed as the cervix tends to close down after removal of Foley’s catheter.
PGE2 gel is expensive, twice as much as the price of Foley’s catheter, also it has to be stored in the refrigerator below 2oc temperature and as seen in our study the side effects of PGE2 like nausea, vomiting, diarrhoea are quite frequent, whereas they are absent in Foley’s catheter.
Failure of PGE2 gel or Foley’s catheter, requires reinstillation of PGE2 gel, however no failures were recorded in our study.
Further, cases of uterine hypertonicity and foetal bradycardia have been reported following use of prostaglandins [5] and this necessitates monitoring of the foetus even in the preinduction cervical ripening phase, when these potent agents are used, as compared to Foley’s catheter where no such specific or vigilant monitoring is required.
Schreyer and Colleagues [6] in 1987 studied the change in Bishop’s score between Foley’s catheter and intravaginal prostaglandin gel and found that 13% had hypertonic contraction as compared to our study where it was only 2%, this could be due to better experience in not injecting PG gel extraamniotically over the period of years.
In another study by Rouben, Arias and Colleagues [7] the change in Bishop’s score was 66% in Foley’s catheter group as compared to 20% in PG group. In our group primigravidas had equal change in Bishop’s score by both methods, however multigravidas showed 75% improvement by Foley’s catheter as against 50% in PGE2 gel group.
Thus Foley’s catheter from our study have proved to be equally effective for preinduction ripening of cervix in primigravidas and superior to PGE2 in multigravidas. Thus Foley’s catheter is definitely safer, better and cheaper alternative to PGE2 gel and it is definitely recommended where prostaglandins are contraindicated even for the diehard PG supporters.
ACKNOWLEDGEMENTS
We would like to thank our Dean of Seth GS Medical College KEM Hospital, for permitting us to publish this study.
REFERENCES
- Bishop’s EH. Obs Gynec 1964; 24 : 266.
- Ezimokhai M, Nwabinelli JN. The use of Foley’s catheter in ripening the unfavourable cervix prior to induction of labour. British J of Obstet and Gynecol April, 1980; 87 : 281-6.
- Embrey MP, Mollison BG. Journal of Obstet and Gynecol of British Commonwealth 1967;,74 : 44-8.
- Jack Atad and Colleagues. British Journal of Obstet and Gynecol Jan., 1997; 104 : 29-32.
- Machenzia, Embrey. British Journal of Obstet and Gynecol 1978; 84 : 264-8.
- Schreyer P, Sherman and Colleagues. Obstet and Gynecol 1989; 73 : 938.
- Rouben D, Arias F. Obstet and Gynecol 1993; 82 : 290-4.
 |