EVA: Lateral Episiotomy or Not in Vacuum Assisted Delivery in Non-parous Women

Karolinska Institutet (Other)
Overall Status
CT.gov ID
The Swedish Research Council (Other)

Study Details

Study Description

Brief Summary

Nulliparous women with a live singleton pregnancy in cephalic presentation past 34 gestational weeks will be randomized to lateral episiotomy or no episiotomy when operative vaginal delivery by vacuum extraction is indicated. Primary outcome is clinically diagnosed obstetric anal sphincter injury (OASIS) of any degree.

Condition or Disease Intervention/Treatment Phase
  • Procedure: Lateral episiotomy

Detailed Description

The study has started at Danderyd Hospital. Danderyd Hospital is a large teaching hospital affiliated to the Karolinska Institute in Stockholm, Sweden. South General Hospital in Stockholm, Uppsala University Hospital, Falun Hospital, Helsingborg Hospital, Växjö Hospital, Umeå University Hospital, and Gothenburg University Hospital Östra have joined the trial 2017-2019.

Informed consent is collected from nulliparous women with a singelton, live fetus in cephalic presentation, with a planned vaginal delivery and without previous gynecological surgery due to incontinence or genital prolapse. Women can be approached at any time from gestational week 18 until delivery, unless they are in severe pain or discomfort, there is not enough time to consider the information, or any other reason not to obtain consent. The informed consent form is kept at the receiving research department and a note of consent/no consent is made in the obstetric medical file.

At indication for vacuum extraction, the patient's consent is confirmed verbally and allocation is made by sealed opaque envelopes on the vacuum extraction equipment mobile cart. Randomization is performed 1:1 in random permuted blocks generated by an external organization (Karolinska Trial Alliance).

Lateral episiotomy is performed according to the intervention description. A reduction of OASIS from 12.4% to 6.2% can be detected with 80% power and less than 5% risk of alpha-error (p<0.05) with 354 women in each group using Chi-square test comparing two independent proportions in a two-sided test (3% missing outcome). A smaller reduction is clinically valuable, although the risk-benefit relationship between receiving a prophylactic episiotomy and the chance of an intact perineum may limit the feasibility of a larger trial in a setting with a restrictive episiotomy policy. We have obtained ethical approval to randomise a total of 1400 women, which enables us to detect a reduction in OASIS rate at VE from 12.4% to 7.8% (p<0.05). We will perform an interim analysis in order to exclude an unethically large difference (p<0.01) in primary outcome or serious adverse events at 350 randomized women.

Data is collected prospectively through Case Record Forms and the obstetric medical file Obstetrix (Cerner Sverige AB), which covers approximately 98% of deliveries with complete data, and the Swedish Pregnancy Register covering the whole of Sweden from 2015. Using a weblink, questionnaires from the national Perineal Tear Register, are sent out electronically for the follow-up of the study participants. In addition, questionnaires regarding birth satisfaction (BSS-R and CEQ 2.0) are sent at 8 weeks after delivery. Questionnaires regarding sexual function (FSFI and FSDS) and quality of life (Euro-QoL-5D) at delivery and after 12 months.

A follow-up from registers regarding mode of delivery and prevalence of episiotomy and OASIS in subsequent births will be performed at 5 years and 10 years after the index birth.

A substudy takes place in Stockholm, Uppsala, and Helsingborg, where included (randomized) women are examined at 6-12 months after delivery with 2D and 3D endovaginal and anal ultrasound to detect levator and sphincter injuries, measure episiotomy scars, establish POP-Q scores, and evaluate a new questionnaire for pelvic floor function after perineal tears.

Another substudy takes place in Stockholm and Falun, where women who have been asked for consent (both affirmative and non-affirmative responders) as well as midwives who have tried to obtain consent, are invited to a qualitative interview study to explore the recruitment experience of women and midwives.

Study Design

Study Type:
Anticipated Enrollment :
710 participants
Intervention Model:
Parallel Assignment
None (Open Label)
Masking Description:
The allocation will be masked during statistical analyses.
Primary Purpose:
Official Title:
Randomized Controlled Clinical Trial of Lateral Episiotomy Versus no Episiotomy in Vacuum Assisted Delivery in Non-parous Women
Actual Study Start Date :
Jun 30, 2017
Anticipated Primary Completion Date :
Dec 31, 2022
Anticipated Study Completion Date :
Dec 31, 2030

Arms and Interventions

Arm Intervention/Treatment
Experimental: Lateral episiotomy

Lateral episiotomy (left or right) is performed by the attending physician or assisting midwife at crowning of the fetal head in operative vaginal delivery by vacuum extraction. Regular manual perineal support is applied.

Procedure: Lateral episiotomy
When the woman is randomized to episiotomy, lateral episiotomy is performed with scissors on the left or right side of the vaginal opening. Origin of incision is 1.0 - 3.0 cm from the midline/posterior forchette and is cut 3.0 cm or more towards the ischial tuberosity at an angle of 60 degrees from the midline.

No Intervention: No episiotomy

No episiotomy is performed during operative vaginal delivery, unless vitally indicated (for example severe fetal distress). The woman may tear spontaneously. Regular manual perineal support is applied.

Outcome Measures

Primary Outcome Measures

  1. Obstetric anal sphincter injury [1 hour]

    Rupture or tear of the external and/or internal anal sphincter at any degree (third and fourth degree perineal tear); International Classification of Diseases (ICD)-10 O70.2 or O70.3.

Secondary Outcome Measures

  1. Other degree of perineal or vaginal tear [1 hour]

    Rupture, tear or hematoma in the perineum or vagina; International Classification of Diseases (ICD)-10 O70.0, O70.1, O70.9, O71.4-9.

  2. Maternal blood loss at delivery [6 hours]

    Estimated blood loss in milliliters through weighing of sheets and drapes during and up to 6 hours after delivery.

  3. Neonatal scalp injury [24 hours]

    Prevalence (number of patients) of scalp injury to the neonate after instrumental delivery, such as open wounds, cephalic hematoma, subgaleal hematoma, and intracranial hemorrhage, according to diagnose by neonatologist.

  4. Pain experience [1 day, 8 weeks, 1 year]

    VAS (0-10) estimated pain through questionnaire at baseline (first days post partum), 8 weeks and 12 months after delivery and at 8 weeks through questionnaires: number of days using analgetic medication.

  5. Birthing experience [8 weeks]

    Questionnaire at 8 weeks after delivery regarding patient satisfaction using the Birth Satisfaction Scale Revised (short form) and the Childbirth Experience Questionnaire 2.0.

  6. Anal incontinence [8 weeks, 1 year, and 5 years]

    Questionnaire at baseline, 8 weeks, 1 year, and 5 years after delivery through the Swedish Obstetrical Tear Register regarding anal continence function (Wexner score based).

  7. Sexual function [1 year and 5 years]

    Questionnaire at baseline (first day post partum), 1 year, and 5 years after delivery through the Swedish Obstetrical Tear Register, as well as FSFI and FSDS Questionnaires.

  8. Pelvic organ prolapse symptoms [1 year and 5 years]

    Questionnaire at baseline, 1 year, and 5 years after delivery through the Swedish Obstetrical Tear Register regarding symptoms of pelvic organ prolapse.

  9. Quality of life score [1 year and 5 years]

    Assessment of quality of life by questionnaire at baseline, 1 year, and 5 years using the Euro-QoL-5D

  10. Mode of delivery in subsequent birth [5 years and 10 years]

    Register data will be extracted from the Swedish Pregnancy Register.

  11. Prevalence of obstetric anal sphincter injury in subsequent birth [5 years and 10 years]

    Register data will be extracted from the Swedish Pregnancy Register.

  12. Prevalence of episiotomy in subsequent birth [5 years and 10 years]

    Register data will be extracted from the Swedish Pregnancy Register.

Eligibility Criteria


Ages Eligible for Study:
18 Years and Older
Sexes Eligible for Study:
Accepts Healthy Volunteers:
Inclusion Criteria:
  • Nulliparous women,18 years old or more, able to give written informed consent in Swedish or English, with a live singleton pregnancy, in a cephalic presentation over 34 completed gestational weeks with a medical indication of vacuum extraction.
Exclusion Criteria:
  • Previous vaginal or perineal surgery for incontinence or genital prolapse, any contra-indication to vacuum extraction (ie fetal disorder or malformation).

Contacts and Locations


Site City State Country Postal Code
1 Falun Hospital Falun Sweden
2 Östra Hospital Gothenburg University Göteborg Sweden
3 Helsingborg Hospital Helsingborg Sweden
4 Danderyd Hospital Stockholm Sweden
5 South General Hospital Stockholm Sweden
6 Umeå University Hospital Umeå Sweden
7 Uppsala University Hospital Uppsala Sweden
8 Växjö Hospital Växjö Sweden

Sponsors and Collaborators

  • Karolinska Institutet
  • The Swedish Research Council


  • Principal Investigator: Sophia Brismar Wendel, MD, PhD, Karolinska Institutet Danderyd Hospital

Study Documents (Full-Text)

More Information


Responsible Party:
Sophia Brismar Wendel, MD, PhD, Dept of Women's health, Danderyd Hospital, Karolinska Institutet
ClinicalTrials.gov Identifier:
Other Study ID Numbers:
  • 2015/1238-31/2
First Posted:
Dec 30, 2015
Last Update Posted:
Mar 28, 2022
Last Verified:
Mar 1, 2022
Individual Participant Data (IPD) Sharing Statement:
Plan to Share IPD:
Studies a U.S. FDA-regulated Drug Product:
Studies a U.S. FDA-regulated Device Product:
Keywords provided by Sophia Brismar Wendel, MD, PhD, Dept of Women's health, Danderyd Hospital, Karolinska Institutet
Additional relevant MeSH terms:

Study Results

No Results Posted as of Mar 28, 2022