Study on Fewer Tears (SOFT) - The Effect of Local Anesthesia on the Incidence of Perineal Tears in the First Vaginal Birth (SOFT)

The SOFT study investigates whether local anaesthesia during the second stage of labor decreases the incidence of perineal tears, including sphincter injuries, in women with their first vaginal birth (non-instrumental).

Study Overview

• Status: Enrolling by invitation
• Conditions: Perineal Laceration, Tear, or Rupture During Delivery
• Intervention / Treatment: Other: Perineal protection techniques

Detailed Description

Introduction Perineal tears are the most common complications of vaginal birth. Severe tears can cause long-term physical and psychological morbidity. Preliminary observations suggest that pudendal block and perineal infiltration with local anaesthesia may relax the pelvic floor muscles, reduce pain, and facilitate a more controlled pushing phase. The SOFT study investigates whether local anaesthesia during the second stage of labor decreases the incidence of perineal tears, including sphincter injuries, in women with their first vaginal birth (non-instrumental).

Materials and Methods Data collection for a prospective observational study is ongoing at Danderyd University Hospital. The study documents perineal protection techniques and the incidence of perineal tears in women with their first vaginal birth (non-instrumental). Findings from this preparatory study will guide the design of a randomized, double-blind, controlled trial to evaluate whether pudendal block and perineal infiltration with mepivacaine or placebo have a protective effect on perineal trauma.

The aim is to include 1,350 participants in this observational study. Midwives complete a case report form indicating the use of manual perineal protection, fetal presentation and position, the duration of the second stage, the detailed degree of perineal tear, pain management during the pushing phase, and the need for local anaesthesia during suturing. The full analysis will evaluate associations among perineal protection techniques, local anaesthesia, and the incidence and severity of perineal tears.

• Study Type: Observational
• Enrollment (Estimated): 1350

Contacts and Locations

Study Locations

• Sweden
  • Stockholm, Sweden, 18288
    • Danderyd Hospital

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult
• Accepts Healthy Volunteers: No

• Sampling Method: Non-Probability Sample

Study Population

Women 18-64 years undergoing their first vaginal birth which is non-instrumental with one or more live fetuses, all presentations accepted, at gestational week 34+0 or more.

Description

Inclusion Criteria:

• Pregnant individuals giving birth.
• Live fetus/fetuses.
• Gestational week 34 or more at birth.
• First vaginal birth, i.e., individuals with prior cesarean section can be included.

Exclusion Criteria:

• Intrauterine fetal death or stillbirth.
• Labor resulting in cesarean section or instrumental delivery.

Study Plan

How is the study designed?

Number of groups / cohorts

1

Cohorts and Interventions

Group / Cohort

Intervention / Treatment

First vaginal birth; Women having their first vaginal birth, which is non-instrumental.

Other: Perineal protection techniques; Perineal protection techniques used by the midwife during a non-instrumental vaginal birth including wet-warm compresses, verbal guidance, oil/gel, perineal massage, two midwives support, pressure relieving position, manual control of the speed of the head's birth, two-step technique, C-grip or Finnish grip for manual perineal protection, supporting the perineum during the delivery of the shoulders, breathing technique during pushing, water birth, acupuncture.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Second-degree perineal injury or worse	Perineal injury after childbirth diagnosed clinically resulting in the diagnostic codes O701, O702, or O703 (i.e. second, third or fourth degree injury).	Within 24 hours of birth

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
OASI	Perineal injury affecting the external or internal anal sphincter muscles (third- or fourth-degree tear, O702 or O703).	Within 24 hours from birth
Episiotomy	Any incision or cut in the perineum to enlarge the vaginal opening during birth.	Immediately at birth.

Other Outcome Measures

Outcome Measure	Measure Description	Time Frame
Perineal or vaginal injury of any degree	All types of tears and injuries resulting from and diagnosed at childbirth.	Within 24 hours from birth

Collaborators and Investigators

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

Study record dates

Study Major Dates

• Study Start (Actual): October 20, 2025
• Primary Completion (Estimated): October 20, 2027
• Study Completion (Estimated): October 20, 2027

Study Registration Dates

• First Submitted: March 24, 2026
• First Submitted That Met QC Criteria: March 24, 2026
• First Posted (Actual): March 30, 2026

Study Record Updates

• Last Update Posted (Actual): April 13, 2026
• Last Update Submitted That Met QC Criteria: April 7, 2026
• Last Verified: April 1, 2026

More Information

Terms related to this study

• Keywords: pudendal nerve block; vaginal birth; local anesthesia; midwifery; childbirth; Perineal injury; perineal protection techniques
• Additional Relevant MeSH Terms: Wounds and Injuries; Lacerations
• Other Study ID Numbers: 2025-04140-01; ASN 2026-1615 (Other Identifier: Region Stockholm Database on Clinical Trials)

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: UNDECIDED
• IPD Plan Description: IPD can be shared with other researchers upon reasonable request, provided ethical approval and all applicable requirements have been met.

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No