Comparison of the Effects of Evening Primrose Oil and Cervical Strip on Induction of Cervical Ripening and Birth Outcomes in Nulliparous Patients with Post-Term Pregnancies: A Clinical Trial Study
Determination of Bishop Score in Nulliparous Women Undergoing Evening Primrose Oil Intervention and Cervical Strip Before and After the Intervention
Design
A clinical trial with a control group, parallel groups, single-blind, randomized, was conducted on 46 patients. Block balanced randomization was used for patient randomization.
Settings and conduct
Women preparing for natural childbirth who attend the clinic at Imam Khomeini Hospital, Mazandaran University of Medical Sciences, Sari, Iran, will be randomly assigned to intervention and control groups. The intervention group will receive vaginal tablets inserted, while the control group will undergo a strip test. Patients are informed about the intervention and have given their consent, but the outcome assessor is unaware of the intervention, and blinding has been implemented.
Participants/Inclusion and exclusion criteria
Inclusion criteria: Week 40 of pregnancy (from LMP or NT)،Women without contraindications for the use of evening primrose oil; Exclusion criteria: Rupture of fetal membranes during cervical preparation, Causing potential side effects from the medication, such as headaches
Intervention groups
Intervention group :Insertion of a 500 mg vaginal evening primrose oil capsule (Barij Essence Company, official packaging) into the cervix by the researcher
control group:Cervical strip performed by a trained researcher every 48 hours
Main outcome variables
Bishop score average
General information
Reason for update
Acronym
IRCT registration information
IRCT registration number:IRCT20251218068375N1
Registration date:2026-02-17, 1404/11/28
Registration timing:prospective
Last update:2026-02-17, 1404/11/28
Update count:0
Registration date
2026-02-17, 1404/11/28
Registrant information
Name
Zahra Rahmani
Name of organization / entity
Country
Iran (Islamic Republic of)
Phone
+98 11 3337 0886
Email address
z.rahmani1972@gmail.com
Recruitment status
Recruitment complete
Funding source
Expected recruitment start date
2026-03-21, 1405/01/01
Expected recruitment end date
2026-09-21, 1405/06/30
Actual recruitment start date
empty
Actual recruitment end date
empty
Trial completion date
empty
Scientific title
Comparison of the Effects of Evening Primrose Oil and Cervical Strip on Induction of Cervical Ripening and Birth Outcomes in Nulliparous Patients with Post-Term Pregnancies: A Clinical Trial Study
Public title
The Effect of Evening Primrose Oil on Cervical Ripening
Purpose
Treatment
Inclusion/Exclusion criteria
Inclusion criteria:
Week 40 of pregnancy (from LMP or NT)
First pregnancy
Willingness to participate in the study
Age over 18 years
A healthy pregnant woman without underlying conditions.
Women without contraindications for the use of evening primrose oil
There is no contraindication for natural childbirth.
Singleton pregnancy
Normal fetal heart rate pattern, absence of uterine contractions, healthy fetal membranes.
Exclusion criteria:
Rupture of fetal membranes during cervical preparation
Causing potential side effects from the medication, such as headaches
Individuals with a history of epilepsy
Age
From 18 years old to 40 years old
Gender
Female
Phase
3
Groups that have been masked
Outcome assessor
Sample size
Target sample size:
46
Randomization (investigator's opinion)
Randomized
Randomization description
The patient randomization list will be generated using the block balanced randomization method with the help of the website Randomization.com, specifically from the original generator section, using blocks of four. The generated list will then be placed sequentially into sealed envelopes. After preparing the sealed envelopes, the list will be destroyed. The researcher who generates the randomization list will have no involvement in the intervention process. Patients will be enrolled in the study according to the order of the randomization list and the contents of the envelopes.
Blinding (investigator's opinion)
Single blinded
Blinding description
Outcome assessor (second midwife or blinded gynecologist): examination and recording of Bishop score and other clinical outcomes
Placebo
Not used
Assignment
Parallel
Other design features
Secondary Ids
empty
Ethics committees
1
Ethics committee
Name of ethics committee
Mazandaran University of Medical Sciences Ethics Committee
Street address
No. 245, Mazandaran University of medical Sciences, Joibar Bolvar, Sari
City
Sari
Province
Mazandaran
Postal code
4817844718
Approval date
2025-11-26, 1404/09/05
Ethics committee reference number
IR.MAZUMS.REC.1404.436
Health conditions studied
1
Description of health condition studied
Childbirth
ICD-10 code
ICD-10 code description
Primary outcomes
1
Description
Bishop score average
Timepoint
Once daily for a maximum of 5 consecutive days
Method of measurement
Vaginal examination and assessment of the Bishop score
Secondary outcomes
empty
Intervention groups
1
Description
Intervention group: Insertion of 500 mg vaginal capsules of evening primrose oil (Barij Essence Company, official packaging) by the researcher and evaluation for 5 days
Category
Treatment - Drugs
2
Description
Control group: Cervical strip performed by a trained researcher every 48 hours
Category
Treatment - Other
Recruitment centers
1
Recruitment center
Name of recruitment center
Imam Khomeini Hospital, Sari
Full name of responsible person
Zahra Rahmani
Street address
no .232,Razi St
City
Sari
Province
Mazandaran
Postal code
4817718743
Phone
+98 11 3336 1700
Fax
+98 11 3336 1702
Email
emamsari.hospital@gmail.com
Web page address
https://imamhospital.mazums.ac.ir
Sponsors / Funding sources
1
Sponsor
Name of organization / entity
Mazandaran University of Medical Sciences
Full name of responsible person
Ahmad Ali Enayati
Street address
no.242 , Third floor, Mazandaran University of Medical Sciences, Joybar street, Sari.
City
sari
Province
Mazandaran
Postal code
۳۳۱۳۱ -۴۸۱۶۶
Phone
+98 11 3336 5724
Fax
+98 11 3336 3754
Email
aenayati۱۳۷۲@gmail.com
Web page address
https://jhc.mazums.ac.ir/person/28
Grant name
Grant code / Reference number
Is the source of funding the same sponsor organization/entity?
Yes
Title of funding source
Mazandaran University of Medical Sciences
Proportion provided by this source
100
Public or private sector
Public
Domestic or foreign origin
Domestic
Category of foreign source of funding
empty
Country of origin
Type of organization providing the funding
Academic
Person responsible for general inquiries
Contact
Name of organization / entity
Mazandaran University of Medical Sciences
Full name of responsible person
Zahra Rahmani
Position
Associate professor
Latest degree
Subspecialist
Other areas of specialty/work
Gynecology and Obstetrics
Street address
no .233, Imam Khomeini Hospital, Razi Street
City
sari
Province
Mazandaran
Postal code
۳۳۱۳۱ -۴۸۱۶۶
Phone
+98 11 3335 0670
Email
z.rahmani1972@gmail.com
Web page address
https://imamhospital.mazums.ac.ir/URL/Page-J94HU
Person responsible for scientific inquiries
Contact
Name of organization / entity
Mazandaran University of Medical Sciences
Full name of responsible person
Zahra Rahmani
Position
Associate professor
Latest degree
Subspecialist
Other areas of specialty/work
Gynecology and Obstetrics
Street address
no .233, Imam Khomeini Hospital, Razi Street
City
sari
Province
Mazandaran
Postal code
۳۳۱۳۱ -۴۸۱۶۶
Phone
+98 11 3335 0670
Fax
+98 11 3336 3754
Email
z.rahmani1972@gmail.com
Web page address
https://imamhospital.mazums.ac.ir/URL/Page-J94HU
Person responsible for updating data
Contact
Name of organization / entity
Mazandaran University of Medical Sciences
Full name of responsible person
Zahra Rahmani
Position
Associate professor
Latest degree
Subspecialist
Other areas of specialty/work
Gynecology and Obstetrics
Street address
no .233, Imam Khomeini Hospital, Razi Street
City
sari
Province
Mazandaran
Postal code
۳۳۱۳۱ -۴۸۱۶۶
Phone
+98 11 3335 0670
Fax
+98 11 3336 3754
Email
z.rahmai1976@gmail.com
Web page address
https://imamhospital.mazums.ac.ir/URL/Page-J94HU
Sharing plan
Deidentified Individual Participant Data Set (IPD)
No - There is not a plan to make this available
Justification/reason for indecision/not sharing IPD
There is no additional information
Study Protocol
Undecided - It is not yet known if there will be a plan to make this available
Statistical Analysis Plan
Undecided - It is not yet known if there will be a plan to make this available
Informed Consent Form
Undecided - It is not yet known if there will be a plan to make this available
Clinical Study Report
Undecided - It is not yet known if there will be a plan to make this available
Analytic Code
Undecided - It is not yet known if there will be a plan to make this available
Data Dictionary
Undecided - It is not yet known if there will be a plan to make this available