Levator Hiatal Dimensions and Mode of Delivery (LEVDIM)

The aim of this observational study is to learn about how muscle dimensions of the pelvic floor measured during pregnancy in primigravida impact birth mecanics and mode of delivery. Tha main aims are to 1. Explore associations between mode of delivery and hiatal dimensions measured by transperineal ultrasound antenatally and 2. Explore the association between duration of 2nd stage of labour and hiatal dimensions.

A pelvic floor ultrasound examination will be performed between pregnancy week 12 and 20 and levator ani muscle hiatal dimensions will be compared between women having a normal vaginal delivery and women with emergency cesarean or operative vaginal deliveries.

Study Overview

• Status: Not yet recruiting
• Conditions: Childbirth Problems; Pelvic Floor Dyssynergia; Pelvic Floor; Rupture
• Intervention / Treatment: Other: Transperineal ultrasound

Detailed Description

The women will be enrolled and examined at the 12-week routine ultrasound examination after informed consent and examined again at the 18 weeks gestation examination. The women will be examined in the supine position on a bed with knees and hips semi-flexed and abducted. Bladder and bowel should be emptied prior to the examination. They will be instructed in how to perform pelvic floor contraction and maximal Valsalva maneuver.

First, a 2D scan will be performed of one experienced clinician. The average of 3 2D levator hiatal anteroposterior measurements will be stored. Then, a 3D/4D ultrasound examination of the pelvic floor will be performed using a Voluson S10, E8 or E10 (GE healthcare, Zipf, Austria) device with a RAB 4-8 MHz curved array transducer with the acquisition angle set at 85 degrees. Offline analysis of the ultrasound volumes will be performed using the 4D view (GE Healthcare, Austria) software, blinded to all clinical data. Hiatal anteroposterior diameter will be measured in both 2D and 3D. Hiatal area and hiatal transverse diameter will be measured in the 3D volume. These measures have previously been demonstrated to have high interrater and intrarater reliability in women in this study population.

Details regarding maternal height, weight, age, ethnicity, marital status, employment, induction of labour, duration of active 2nd stage of labour, gestational length, use of epidural analgesia, indication for operative delivery (slow progress or fetal distress), mode of delivery (forceps, vacuum, cesarean section), infant birthweight, head circumference, Presentation (occiput anterior/ posterior), head station at intervention, infant gender, Apgar score, perineal trauma, postpartum hemorrhage, will be collected from electronic patient journals after delivery. The women will be informed that they may be contacted within 2 years after delivery for a follow up, but separate consent will be needed.

Participants will have a unique study number and the coupling list will be stored on a safe area at St. Olav's server.

• Study Type: Observational
• Enrollment (Estimated): 400

Contacts and Locations

• Study Contact: Name: Ingrid Volløyhaug, PhD; Phone Number: +47 97549124; Email: ingrid.volloyhaug@ntnu.no
• Study Contact Backup: Name: Maria Nyhus, PhD; Phone Number: +47 41646649; Email: maria.o.nyhus@ntnu.no

Study Locations

• Norway
  • Levanger, Norway
    • Levanger sykehus
    • Contact: Ane Bergquist, MD; Phone Number: +47 90876381
  • Trondheim, Norway
    • St.Olavs Hospital
    • Contact: Ingrid Volløyhaug; Phone Number: 97549124; Email: ingrid.volloyhaug@ntnu.no
    • Contact: Maria Nyhus; Phone Number: 41646649; Email: maria.o.nyhus@ntnu.no

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: Yes

• Sampling Method: Probability Sample

Study Population

400 nulliparous pregnant women recruited at routine ultrasound scan i nearly pregnancy

Description

Inclusion Criteria

• Age over 18 years
• Ability to consent
• Singleton pregnancy

Exclusion criteria

• Previous deliveries > 16 weeks gestation
• Previous pelvic floor surgery
• Anomalies affecting the pelvic floor function (such as myelomeningocele)
• Epilepsy, since this might influence intervention during delivery
• Women with elective cesarean

Study Plan

How is the study designed?

Number of groups / cohorts

1

Cohorts and Interventions

Group / Cohort

Intervention / Treatment

Pregnant women

Other: Transperineal ultrasound; A 2D scan will be performed of one experienced clinician. The average of 3 2D levator hiatal anteroposterior measurements will be stored. Then, a 3D/4D ultrasound examination of the pelvic floor will be performed using a Voluson S10, E8 or E10 (GE healthcare, Zipf, Austria) device with a RAB 4-8 MHz curved array transducer with the acquisition angle set at 85 degrees. Offline analysis of the ultrasound volumes will be performed using the 4D view (GE Healthcare, Austria) software, blinded to all clinical data. Hiatal anteroposterior diameter will be measured in both 2D and 3D. Hiatal area and hiatal transverse diameter will be measured in the 3D volume

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Mode of delivery	Normal vaginal, vacuum assisted vaginal, forceps assisted vaginal or emergency cesarean delivery	Assessed at 1 day of childbirth
Levator hiatal dimensions	levator hiatal anteroposterior diameter and levator hiatal area at rest measured with 2D and 3D ultrasound	Measured in pregnancy week 12
Levator hiatal dimensions	levator hiatal anteroposterior diameter and levator hiatal area at rest measured with 2D and 3D ultrasound	Measured in pregnancy week 18

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Duration of second stage of delivery	Number of minutes from full dillatation of the cervix until the baby is born	Assessed at 1 day of childbirth
Pernineal tears	Grade of perineal tear. No tear, grade 1, 2, 3, 4 or deep vaginal tear	Assessed at 1 day of childbirth
Postpartum haemorrage	Amount in ml of postpartum haemmorage	Assessed at 1 day of childbirth
womans experience of transperineal ultrasound	Qualitative assessment of the womans experience of transperineal ultrasound	Assessed at pregnancy week 12 and week 18
Interrater validity of ultrasound measurements	For analysis of intrarater reliability for ultrasound measurements, we will use the intraclass correlation coefficient (ICC) two-way mixed effects, absolute agreement model. To determine interrater reliability, we will use the ICC two-way random effects, absolute agreement model, applying both the mean of three raters and single measurements. [20]. The following ICC cut-offs will be applied: < 0.20 = poor reliability, 0.20-0.40 = fair reliability, 0.41-0.60 = moderate reliability, 0.61-0.80 = good reliability and > 0.80 = excellent reliability	Assessed 3 months after childbirth

Collaborators and Investigators

• Sponsor: St. Olavs Hospital
• Investigators: Principal Investigator: Ingrid Volløyhaug, PhD, St. Olavs Hospital

Study record dates

Study Major Dates

• Study Start (Estimated): February 5, 2024
• Primary Completion (Estimated): October 1, 2025
• Study Completion (Estimated): October 1, 2025

Study Registration Dates

• First Submitted: January 19, 2023
• First Submitted That Met QC Criteria: May 8, 2023
• First Posted (Actual): May 9, 2023

Study Record Updates

• Last Update Posted (Actual): December 29, 2023
• Last Update Submitted That Met QC Criteria: December 28, 2023
• Last Verified: December 1, 2023

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Nervous System Diseases; Neurologic Manifestations; Wounds and Injuries; Dyskinesias; Rupture; Ataxia
• Other Study ID Numbers: 423957

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO