Levator Hiatal Dimensions and Mode of Delivery

Not yet recruiting

• Conditions: Pelvic Floor; Rupture; Pelvic Floor Dyssynergia; Childbirth Problems
• Interventions: Other: Transperineal ultrasound

• Registration Number: NCT05849584
• Lead Sponsor: St. Olavs Hospital

Brief Summary

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.

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 Timeline

• Study First Submitted: 2023-01-19
• Study First Submitted QC: 2023-05-08
• Study First Posted: 2023-05-09
• Status Verified: 2023-12
• Last Update Submitted: 2023-12-28
• Last Update Posted: 2023-12-29
• Study Start: 2024-02-05
• Primary Completion: 2025-10-01
• Study Completion: 2025-10-01

Recruitment & Eligibility

• Status: NOT_YET_RECRUITING
• Sex: Female
• Target Recruitment: 400

Inclusion Criteria

Not provided

Exclusion Criteria

Not provided

Study & Design

• Study Type: OBSERVATIONAL
• Study Design: Not specified

Arm && Interventions

Group	Intervention	Description
Pregnant women	Transperineal ultrasound	-

Primary Outcome Measures

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

Secondary Outcome Measures

Name	Time	Method
Pernineal tears	Assessed at 1 day of childbirth	Grade of perineal tear. No tear, grade 1, 2, 3, 4 or deep vaginal tear
Postpartum haemorrage	Assessed at 1 day of childbirth	Amount in ml of postpartum haemmorage
womans experience of transperineal ultrasound	Assessed at pregnancy week 12 and week 18	Qualitative assessment of the womans experience of transperineal ultrasound
Duration of second stage of delivery	Assessed at 1 day of childbirth	Number of minutes from full dillatation of the cervix until the baby is born
Interrater validity of ultrasound measurements	Assessed 3 months after childbirth	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

Trial Locations

Locations (2)

st.Olavs hospital; 🇳🇴 Trondheim, Norway

Levanger Sykehus; 🇳🇴 Levanger, Norway