Modifying Cervical Bishop Scoring System

Bishop Score; Are Further Modifications Needed?

To have an early more precise way to predict failed induction in patients undergoing elective termination of pregnancy & those more likely to undergo caesarian section,this will Spare patients with decreased chances of favorable induction a long and exhausting trial of labour with increased probability of complications and an emergency caesarian

Study Overview

• Status: Completed
• Conditions: Failed Induction of Labor
• Intervention / Treatment: Other: bishop score calculation; Other: Trans-vaginal ultrasound; Other: Modified bishop score calculation; Procedure: labour induction

Detailed Description

After approval of the ethical & scientific committees of the OBGYN department of Kasr El Aini hospital, 80 primigravidas undergoing induction of labour at our hospital in a prospective blind study were subjected to history taking, examination, investigations & ultrasonography. Indication for pregnancy termination was explained to each patient and a written consent was obtained.

Clinical examination & assessment:

Patients were examined vaginally by the attending physician and a Bishop score was assigned and recorded according to the original bishop scoring system 1964 (Bishop EH, 1964) as seen in table 1.

Table 1: The Bishop score (Bishop EH, 1964):

0 points : for no dilation, effacement 0-30%, station -3, firm consistency & posterior position of cervix

1. point : for dilation 1-2 cm, effacement 40-50%, station -2, medium consistency & mid position of cervix.
2. points: for dilation 3-4 cm, effacement 60-70%, station -1, soft consistency & Anterior position of cervix.
3. points: for dilation 5-6 cm, effacement 80%, station +1 or +2.

Sum of the points in each criteria assessed will be the bishop score.

Trans-vaginal ultrasound assessment of cervical length was performed using the same machine each time Sonoace x4 (samsung Medison Co., Ltd. Seoul, South Korea) following a standardized technique in which the bladder was emptied & the vaginal probe 6.5MHz was introduced into the vagina and manipulated so that the main anatomical landmarks (bladder, fetal presentation, cervical canal, internal and external cervical os) were identified. The hyper echoic line extending from the internal os to external os, was identified by fine manipulations of the probe. The cervical canal length was measured as the distance between the internal and external os, while presence of funneling was recorded. Funneling was defined as a (V)or (U) shaped indentation of the internal os. In the presence of funneling, the length of an associated funnel was not included as part of the cervical length, and the measurement was taken from the apex of the funnel to the external os.

A modified bishop score was devised for the purpose of this study, which aimed to incorporate cervical length into the bishop scoring system. This score was calculated by addition or subtraction of the figure obtained respectively for cervical length in table 2 from the original bishop score.

Table 2: Scoring System for respective cervical length

Score: -2 for Cervical length > 2.5cm by trans-vaginal ultrasound. Score: -1 for Cervical length 2 - 2.5 cm by trans-vaginal ultrasound.

Score: 0 for Cervical length 1.6 - 1.9 cm by trans-vaginal ultrasound.

Score: +1 for Cervical length 1 - 1.5 cm by trans-vaginal ultrasound.

Score: +2 for Cervical length < 1 cm by trans-vaginal ultrasound.

We think an unfavorable score should decrease the value of the bishop score, and not just fail to increase it (in comparison to the original score) & hence our negative value for unfavorable cervical length. The values used to set the figures for the max and min score for cervical length in table 2 were based on our observation of how several studies displayed the range of their results for cervical length and how we think that it should impact the bishop score. There is no exact pre-set cut off value for what a favorable cervical length should be.

Labour induction and Monitoring:

Induction of labor was carried out as per our hospital's standard protocol, in which patients with unfavorable cervical examination i.e. bishop score of 4 or less were given dinoprostone 3mg (Dinoglandin E2 ® Egypharma Nasr City Cairo Egypt) vaginal tablet, with re-dosing intervals every six hours if no significant cervical changes were noted.

In cases where the initial bishop score was 5 or more, or improvement was seen after dinoprostone, Oxytocin was initiated for induction. In cases already having one or more dinoprostone vaginal tablets, oxytocin was started four hours after the final dinoprostone dose, using the low-dose protocol beginning with 2 mU/min (and increase by 2 mU/min) at incremental time intervals (15 - 30 minutes). The goal was to reach satisfactory contractions (3-5 per ten minutes with each contraction lasting 45 seconds), & to avoid uterine hyperstimulation.

All through induction & labor fetal heart rate was measured every 30 minutes in first stage of labor and every 10 minutes in second stage of labor. Progress of labor was observed & recorded, the total amount of oxytocin used, fetal weight and Apgar score for each baby were recorded. The total time taken till reaching active phase of labor, total time taken till delivery & mode of delivery were recorded. Any decision to proceed to caesarean was reviewed by a senior consultant and the indication was noted. Any case undergoing caesarean for any indication other than failure of progress will be omitted from the results.

• Study Type: Observational
• Enrollment (Actual): 80

Contacts and Locations

Study Locations

• Egypt
  • Cairo
    • Garden City, Cairo, Egypt, 11562
      • 11562

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 20 years to 34 years (Adult)
• Accepts Healthy Volunteers: No
• Genders Eligible for Study: Female

• Sampling Method: Probability Sample

Study Population

80 primigravidas undergoing induction of labour at our hospital in a prospective study were subjected to history taking, examination, investigations & ultrasonography. Indication for pregnancy termination was explained to each patient and a written consent was obtained.

Description

Inclusion Criteria:

1. Primigravida Singleton pregnancy with mature fetus at term indicated for termination of pregnancy.
2. Cephalic presentation.
3. Medical indications for termination of pregnancy e.g.: Pre-eclampsia, uncontrolled diabetes at term..e.t.c,
4. Post-term pregnancy.
5. Fetal indication: signs of fetal compromise e.g.: decreased biophysical profile, poor umbilical Doppler indices, diminished liquor.
6. premature rupture of membranes (PROM) not going into spontaneous labor within 24 hours since onset.
7. Intrauterine fetal death (IUFD).

Exclusion Criteria:

1. they had true labor pains or clear onset of labor as diagnosed by cervical changes.
2. Previous uterine surgery (scared uterus).
3. Cephalo-pelvic disproportion.
4. Mal-presentations
5. Severe oligo-hydramnios i.e.: amniotic fluid index Less than 5.
6. Twin pregnancy.
7. Fetal macrosomia. -Growth beyond a specific threshold (weight above 4000g) 8) Placenta previa.

9) Fetal bradycardia in case of living fetus.

Study Plan

How is the study designed?

Design Details

• Observational Models: Case-Only
• Time Perspectives: Prospective

Number of groups / cohorts

1

Cohorts and Interventions

Group / Cohort

Intervention / Treatment

Labour Induction; 80 primigravidas undergoing bishop score calculation, trans-vaginal ultrasound assessment of cervical length &, Modified bishop score calculation, then induction of labour at our hospital.

Other: bishop score calculation; Assessment of bishop score by vaginal examination; Other: Trans-vaginal ultrasound; trans-vaginal ultrasound assessment of cervical length.; Other: Modified bishop score calculation; using the cervical length and the original bishop score to calculate modified bishop score; Procedure: labour induction; Induction of labor was carried out as per our hospital's standard protocol.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Area Under Receiver Operating Characteristic Curve (ROC) for Modified Bishop Score	to predict failed induction and comparing it to the area under curve for bishop score to find out which test is more accurate in predicting caesarean section, The positive actual state is failed induction and performing Caesarean Section.The positive actual state is failed induction, the true positive rate (Sensitivity) is plotted in function of the false positive rate (100-Specificity). So as the numbers approaches 1, induction fails, the Y-axis of the curve is sensitivity and the x- axis is (1-specificity).	5 months

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Area Under Curve for The Bishop Score	to predict failed induction and comparing it to the area under curve for modified bishop score to find out which test is more accurate in predicting caesarean section, The positive actual state is failed induction and performing Caesarean Section. The positive actual state is failed induction, the true positive rate (Sensitivity) is plotted in function of the false positive rate (100-Specificity), So as the numbers approaches 1, induction fails, the Y-axis of the curve is sensitivity and the x- axis is (1-specificity).	5 months
Cut Off Value for The Modified Bishop Score	the value at which there a high sensitivity and specificity to predict failed labour induction	5 months
Cut Off Value for Bishop Score	the value at which there a high sensitivity and specificity to predict failed labour induction	5 months

Collaborators and Investigators

• Sponsor: Kasr El Aini Hospital
• Investigators: Principal Investigator: Ahmed M Kamel, M.D, Lecturer Of obstetrics & Gynecology

Publications and helpful links

General Publications

• BISHOP EH. PELVIC SCORING FOR ELECTIVE INDUCTION. Obstet Gynecol. 1964 Aug;24:266-8. No abstract available.

Study record dates

Study Major Dates

• Study Start: July 1, 2014
• Primary Completion (Actual): December 1, 2014
• Study Completion (Actual): December 1, 2014

Study Registration Dates

• First Submitted: December 6, 2014
• First Submitted That Met QC Criteria: December 10, 2014
• First Posted (Estimate): December 11, 2014

Study Record Updates

• Last Update Posted (Estimate): January 16, 2015
• Last Update Submitted That Met QC Criteria: January 8, 2015
• Last Verified: January 1, 2015

More Information

Terms related to this study

• Keywords: cervical length; labour induction; Bishop score; trans-vaginal assessment of cervical length
• Other Study ID Numbers: A13802022