The Effect of Using Dexamethasone Tablets Vaginally On Improving Cervical Bishop Score in Nulliparous Pregnant Women. A Randomized Clinical Trial
Phase: PHASE3
Conditions: Dexamethasone, Pregnancy
Sponsor: Alborz Medical University

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The Effect of Using Dexamethasone Tablets Vaginally for Improving 
Cervical Bishop Score in Nulliparous Pregnant Women: A Randomized Clinical Trial 
 
 
 
NCT number: NCT05070468 
 
Date of the document: 01/09/2021 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 

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Scientific Background 
  
Inducing labor can be required as a therapeutic option. This requires stimulating uterine 
contractions before the spontaneous onset of labor. The most common indications for labor 
induction may include gestational or chronic hypertension, severe fetal growth restriction, 
preeclampsia, eclampsia, gestational diabetes, and post-term pregnancy. Ending a pregnancy can 
be needed when there is premature rupture of membranes without labor, oligohydramnios, or 
concerns related to fetal statuses, such as non-reassuring heart sounds (1, 2). Two primary 
techniques are used for cervical ripening when the cervix is unfavorable to facilitate the ripening 
process. The techniques can be mechanical interventions and/or the application of pharmacologic 
agents. Techniques like the administration of prostaglandins (e.g., Misoprostol), extra amniotic 
saline infusion (EASI), traction on the cervix with a Foley balloon catheter, and/or hygroscopic 
cervical dilators are used (3, 4). In nulliparous pregnant women, the cervix has a smooth, round 
external os. The average time from induction to delivery is between 15 to 20 hours. The cervical 
ripening phase can take up to 12 hours before the start of labor. Labor may be prolonged by about 
10 percent of pregnant women, which can cause maternal and/or fetal risks. These risks include 
antepartum and postpartum hemorrhage and maternal and/or neonatal infection, leading to 
maternal, fetal, or neonatal death (5). Therefore, labor induction is essential in managing prolonged 
labor (6, 7).  
 
Corticotropin-releasing hormone (CRH) is a principal regulator of the hypothalamic-pituitary-
adrenal axis. CRH is released from the placenta and fetal membranes during pregnancy. Plasma 
CRH levels observed during labor peak during vaginal delivery (serum levels ranging from 2 to 
3000 pmol/liter during labor) (6, 8, 9). The CRH functions as the “surveillance and response” for 
the placental. This allows the fetus to detect threats to survival, and if viable, the fetus can adjust 
its developmental course. In 2007, O'Sullivan et al. reported that congenital adrenal hyperplasia in 
the fetus is associated with 21-hydroxylase deficiency. In addition, a late gestational rise may lead 
to impaired cortisol production by the fetal adrenal gland (10). 
 
Studies by Mohaghegh et al. and Latif et al. demonstrated that glucocorticoids like dexamethasone 
play a pivotal role in cervical ripening and aid labor induction (2, 8). Prior studies have used 
dexamethasone as the chosen glucocorticoid to investigate its role in labor induction. The effect 

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of dexamethasone on the interval length at the beginning of labor induction has been explored, as 
its effects at the beginning of the active phase of labor. (3, 8, 11-14). However, there is a paucity 
of studies because of the high heterogeneity among pregnant women. There is a need for double-
blind clinical trials to solidify the use of dexamethasone for improving cervical Bishop scores in 
pregnant women. As outlined, the role of corticosteroids in labor induction remains unclear. The 
effect of using corticosteroids vaginally for labor induction requires further investigations. 
Therefore, we undertook a triple-blinded randomized controlled trial (RCT) where dexamethasone 
was the chosen glucocorticoid used for labor induction. This study aimed to examine the effect of 
using dexamethasone administered vaginally and whether it can enhance the Bishop score and 
reduce the duration of the latent phase of labor in nulliparous pregnant women. 
Methods 
 
Study design 
This was a triple-blinded randomized controlled trial conducted in Kamali Hospital, Karaj, Iran. 
Kamali Hospital is one of the teaching hospital subsets at Alborz University of Medical Sciences. 
Ethical approval was ceded to the ethical committee of Alborz university. The ethics committee 
approved the study protocol. The RCT was conducted between October 2019 and June 2021. It 
was registered as an RCT with the following ID number: IR. ABZUMS. REC1399.067. 
Additionally, it was registered on clinicaltrial.gov, NCT05070468. 
 
A sufficient sample size is required to compare the mean of the two groups (15). Using a 95% 
confidence interval and power of 90%, it was estimated that at least 84 participants were required. 
The participants were randomly divided into two groups of 42 as either cases or controls. The 
statistician assigned the participants to two groups using a balanced block randomization method 
using allocation into quadruple blocks. There were six modes for each case, two participants were 
in the control group, and two were in the intervention group. Thus, the participants were selected 
using the table of random numbers and assigned the numbers one to six within the groups of four. 
 
Objectives 
The clinical trial investigators and researcher staff were involved in all aspects of the study design 
and administration of the RCT. This included screening pregnant patients to assess if they met the 

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study inclusion criteria. These criteria required being a nulliparous Iranian woman pregnant, 
having full-term gestation (≥38 weeks), with a singleton pregnancy, between 18 to 35 years of age, 
and having normal Body Mass Indices (BMI) of 18.5—24.9. Labor induction was started in the 
participants when the membranes ruptured without the initiation of labor. The fetus was required 
to be in cephalic presentation, as shown on an ultrasound; there was a Bishop score of ≤2 and an 
estimated fetal weight of 2500-4000 grams. Participants were expected to have had normal Non-
Stress Test (NST) results. If the patient's obstetric physician indicated termination of pregnancy, 
they could be eligible and randomized into case and control groups by a statistician. 
 
Exclusion criteria required the pregnant woman not to take any hormones or herbal medicines 
(traditional medicines), herbal/natural products, or conventional/prescribed medications during her 
pregnancy. Those who had the following pre-existing diseases, including diabetes mellitus, 
hypertension, a history of obstetric complications such as preeclampsia or eclampsia, or HELLP 
(Hemolysis, Elevated Liver enzymes, and Low Platelets) syndrome, were excluded. If the pregnant 
individual had previously presented with fetal immobility/decelerations or a history of maternal 
bleeding, they could not be enrolled in the clinical trial.  
 
To enroll eligible patients, the investigator explained the study to potential participants and asked 
them to consider being in the study after considering all the presented information. Written consent 
was obtained from all recruited patients. Once enrolled, the patients, investigators, and research 
staff were blinded to which groups the participants were allocated. Dexamethasone and placebo 
tablets were labeled Tablets A and B and delivered by the hospital pharmacist. The research staff 
was blinded to which tablets were the study drug. The study design required that the tablets be 
administered vaginally by the obstetrician. Fourteen dexamethasone tablets (0.5 mg) were 
administered in group A, and 14 placebo tablets were given in the same manner to the participants 
in group B.  
 
Data collection 
Data was collected using several tools, including interviews, observations, and a vaginal 
examination. The research staff designed a 2-page questionnaire which was used, and this included 
demographic information, i.e., current age, education, job, gravidity, parity, past medical history, 

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and BMI. The first and second Bishop scores, the latent phase duration, and delivery and 
intervention type were also recorded for each participant. The collected information was initially 
collected on paper forms.  
 
Clinical intervention phase 
During the intervention phase, the modified Bishop score was assessed; this comprised a physical 
examination that evaluated the cervical length, consistency, dilation and position, and fetal head 
station. Per the study protocol, an obstetrician placed fourteen tablets (either Tablets A or B) within 
the vagina during labor. The fetal heart rate was closely monitored, and any changes in the Bishop 
score within 6 hours were recorded. During this time, an obstetric physician undertook the labor 
induction for the study participants.  
 
There were three types of interventions used. The first was when the pregnant woman did not 
require to be induced. These individuals had effective and robust contractions during labor. 
Therefore, further induction of uterine contractions was not performed, and labor took its natural 
course. Second, labor was induced when the pregnant woman did not have strong enough or 
effective uterine contractions. In these situations, Oxytocin was administered to aid in the 
induction if the patient had a Bishop score of five or more. Third, during labor induction in those 
participants assigned to the cases group, Misoprostol was administered if they had a Bishop score 
of less than 5. Once proper cervix ripening had been achieved, this indicated the termination of 
Misoprostol's effects. Labor induction continued with oxytocin until uterine contractions were 
satisfactory and strong. At each stage, from initial enrollment into the study, the onset of labor 
symptoms, and until the end of the latent phase of labor (4 cm dilation), the research staff followed 
and evaluated the individual women every 30 minutes. To further increase the reliability of the 
examination results, the patient's cervical dilation was established by two separate examiners to 
verify the result of the vaginal examinations. 
 
Statistical analysis 
The statistical analysis collected data from reviewing the participant questionnaires. This was 
converted for analysis using the SPSS statistical software version 25.0 (IBM Corporation, Chicago, 
IL, USA). A chi-squared test was used to assess any statistical hypotheses. Qualitative variables 

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were reported as percentages and frequency. Through the evaluation of data, the findings were 
evaluated by using the Kolmogorov-Smirnov and Shapiro–Wilk tests. Additional parametric and 
nonparametric analyses were performed. The subsequent assessment used the Mann-Whitney or 
T-Test (depending on the case). A p-value of (P≤0.05) was considered statistically significant in 
this study. 
 
 
 
 

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