Introduction
Induction of labour is the process of initiating labour artificially in situations where termination of pregnancy is indicated due to maternal or fetal compromise or when the fetus has crossed the period of viability. Over the past few decades, the incidence of induction of labour has increased owing to the detection of high risk pregnancies which often require prompt intervention to prevent perinatal and maternal morbidity and mortality.1 These high risk pregnancies include but are not limited to complications like pregnancy induced hypertension, Overt/ Gestational diabetes mellitus, Rh alloimmunisation, fetal growth restriction and Oligohydramnios/Polyhydramnios.2, 3
Misoprostol is a synthetic prostaglandin E1 analogue primarily introduced for the prevention and treatment of gastroduodenal ulcers that occurred as a side effect of non steroidal anti-inflammatory drugs.4 Its off label use includes medical termination of pregnancy, induction of labour, cervical dilatation before hysteroscopic procedures and the prevention and management of post partum hemorrhage. In the initial trials, misoprostol for induction of labour in term pregnancy was kept per vaginally in doses of 100 mcg to 200 mcg which was then titrated to 25 mcg to 50 mcg owing to its various side effects.5
Mifepristone, RU 486, is an anti-progesterone which acts mainly on the cervix and accelerates its ripening process and sensitizes the uterus to the action of prostaglandins and oxytocin which helps in the initiation of uterine contractions.6, 7
As a functional withdrawal of progesterone is responsible for the onset of uterine contractions, cervical ripening and dilation, mifepristone is used in this study as a means of induction of labour at term in indicated pregnancies. We have compared the efficacy of oral Tablet Mifepristone and the efficacy of intracervical foleys catheterisation for induction of labour in term pregnancy with respect to the induction-delivery intervals, route of delivery and neonatal outcomes.8, 9
Materials and Methods
In this randomized control study, 180 full term pregnant women visiting Obstetrics and Gynecology OPD of Sir Sayajirao General Hospital (SSGH) were enrolled in the study which was conducted from May 2022 to December 2022 after approval from the Institutional Ethics Committee for Biomedical and Health Research (IECBHR), SSG Hospital, Vadodara.
All the women of the study were chosen based on a strict inclusion and exclusion criteria and unnecessary inductions were avoided.
Inclusion criteria
Singleton pregnancy
Cephalic presentation
Intact membranes
If labour induction was indicated due to maternal/fetal complications which included pregnancy induced hypertension, GDM, Overt DM, IUGR, oligohydramnios, polyhydramnios and fetal congenital malformations.
Delivery could be postponed for 24 hrs
Women with unfavorable cervix (Bishop score less than or equal to 6)
Patients with a reactive NST
Exclusion criteria
Parity more than 4
Previous caesarean section
Suspected or confirmed cephalopelvic disproportion
Macrosomia
Malpresentation
Intrauterine fetal demise
Known hypersensitivity to prostaglandins or mifepristone
Impaired renal, hepatic or adrenal function and antepartum hemorrhage
All eligible women with obstetrical or medical indication for labour induction were enrolled in the study taking inclusion and exclusion criteria in consideration. Participants were briefed about the nature of the study, details of the treatment and a written informed consent was obtained after being explained about the risks and benefits of the study.
A thorough history including patients’ menstrual history, obstetric history and any significant past/family/treatment history was taken and recorded. Complete systemic and obstetric examination was done in all patients. Baseline complete blood count, liver function test and renal function test along with fetal ultrasound with doppler were done in all patients. Per vaginum examination was done to assess the modified bishops score and pelvis.
Patients were randomized into two groups with group A including patients who were given Tablet Mifepristone 200 mg PO and group B including patients who were pre-induced with intracervical foleys catheterization.
Patients in Group A were assessed after 24 hours or after initiation of uterine contractions, whichever was earlier. If modified bishop’s score was < 8, patients were induced with per vaginal insertion of Tablet Misoprostol 25 mcg or 50 mcg depending on parity and if the modified bishop’s score was more than or equal to 8, augmentation was done with intravenous oxytocin (if uterine contractions were confirmed to be inadequate).
Patients in Group B were assessed after expulsion of intracervical foleys bulb. If modified bishop’s score was < 8, patients were induced with per vaginal insertion of Tablet Misoprostol 25 mcg or 50 mcg depending on parity and if the modified bishop’s score was more than or equal to 8, augmentation was done with intravenous oxytocin (if uterine contractions were confirmed to be inadequate).
Electronic fetal heart rate monitoring was performed in all patients in active labour. Artificial rupture of membranes was done when clinically indicated. Augmentation was delayed for six hours after administration of misoprostol. No epidural analgesia used in our study.
A maximum of 3 doses of Tablet Misoprostol 4 were allowed. If after 3 doses of per vaginum misoprostol regular uterine contractions failed to begin, the patient was given a choice of either waiting for the contractions to begin or undergoing emergency LSCS.
Results
Observations were made based on the age and parity of the study participants with specific focus on the following outcomes.
Primary outcome
The interval from administration of oral mifepristone/intracervical foleys catheterisation to vaginal delivery.
Secondary outcome
Out of the total 180 study participants, 90 women were given Tablet Mifepristone 200 mg per orally and 90 women were induced with intracervical foley’s catheterisation. The mean age of group A was 24.18 years and of group B was 24.06 years, as shown in Table 1, and thus are very closely comparable.
Out of 90 study participants in group A, 34 were Primigravida and 56 were Multigravida. Out of 90 study participants in group B, 43 were Primigravida and 47 were Multigravida as shown in Table 2.
As shown in Table 3 the study demonstrated a significant decrease in induction– delivery interval in Group B compared to Group A. The mean induction-delivery interval was 13.34 hours in Group B as compared to 21.82 hours in Group A. This difference in induction-delivery interval between the two groups was found to be statistically significant (p value <0.05).
As shown in Table 4, 87% of women delivered via vaginal delivery in Group A as compared to 77% in Group B. 13% women underwent C section in Group A as compared to 27% in Group B. The reduction in rate of C section between the two groups was statistically insignificant (p value > 0.05).
As shown in Table 5, out of the 11 women who underwent C section in Group A, 4 were because of fetal distress with thick MSL, 3 because of pathological CTG, 1 due to non progression in 1st stage of Labour and 3 due to failed induction. As shown in Table 6, out of the 20 women who underwent C section in Group B, 5 were because of fetal distress with MSL, 7 due to pathological CTG, 2 due to non progression in 1st stage of labour and 6 due to failure of induction. This difference in indications of C sections and their frequency was insignificant (p value > 0.05).
As seen in Table 7, 20% of Primigravida in Group A and 25% of Primigravida in Group B underwent C-Section whereas 7% of Multigravida underwent C-Section in Group A as compared to 19% in Group B. This difference was, however, not statistically significant. (p value > 0.05)
As shown in Table 8, no neonate born in Group A had APGAR score of <7 whereas 2 neonates of Group B were found to have an APGAR score <7 at 1 minute out of which 1 neonate had persistent APGAR score of <7 at 5 minutes and was admitted to the NICU. In Group A, all 90 neonates had APGAR score more than or equal to 7 at 1 minute and 5 minutes whereas 88 neonates in Group B had an APGAR score of more than or equal to 7 at 1 minute and 5 minutes.
Table 1
Distribution of patients according to age
|
|
Induction type |
N |
Mean |
SD |
|
Age |
Group A |
90 |
24.18 |
1.92 |
|
Group B |
90 |
24.06 |
1.93 |
Table 2
Distribution of patients according to parity
|
|
Type of Induction |
|
|
Group A |
Group B |
|
|
Primi gravida |
34 (37.78%) |
43 (47.78%) |
|
Multi gravida |
56 (62.22%) |
47 (52.22%) |
Table 3
Association of induction-delivery interval with the type of induction
|
Induction to Delivery Interval |
Induction type |
N |
Mean |
STD deviation |
|
Group A |
90 |
21.82 |
9.64 |
|
|
Group B |
90 |
13.34 |
5.91 |
Table 4
Association of route of delivery with type of induction
|
Type of Induction |
Route of Delivery |
|
|
Normal Delivery |
C-section |
|
|
Group A |
79 (87.78%) |
11 (12.22%) |
|
Group B |
70 (77.78%) |
20 (22.22%) |
Table 5
Indications for C section (Group A)(Chi-square = 0.19, P = 0.65 at df = 1 (Statistically not significant)
Table 6
Indications for C section (Group B)
Discussion
Our study was conducted at the Department of Obstetrics and Gynaecology, SSG Hospital, Baroda Medical College between May 2022 and December 2022 and included 180 patients out of which 90 patients were given tablet mifepristone 200 mg per orally and 90 were induced with intracervical foleys catheterisation.
Among the study participants 77 women were primigravida and 103 were multigravida.
The mean age of the women in the study group was 24.10 years.
The mean duration of induction-delivery interval was 21.8 hours in Group A whereas it was 13.3 hours in Group B. This difference was statistically significant and was markedly different from the results in the study conducted by Kannan Yelikar.10, 11
87% of women delivered by vaginal delivery in Group A whereas 77% women delivered by vaginal delivery in Group B. 13% women underwent C section in Group A and 27% underwent C section in Group B. These results were comparable to the results obtained in various studies conducted by Lata G et al, Rutuja Athawale, Wing DA.11, 12, 13
In Group A, the incidence of fetal respiratory distress was 7% as compared to 13% in Group B. There were no significant changes in neonatal outcomes in studies by Hapangama and Byrne et al.14, 15
Conclusion
Taking into account the observations we made in this study, we come to the following conclusions:
Due to its significant effect on mode of delivery and neonatal outcome, and despite no decrease in induction delivery interval, Mifepristone may be used as an inducing agent in indicated term pregnancies.
The incidence of fetal distress in patients given oral mifepristone as compared to patients induced with intracervical foleys catheterization was found to be insignificant.
Further study is required to efficiently assess the incidence of tachysystole/ hyperstimulation and fetal distress caused by Mifepristone.
