Pelvic Floor Ultrasound Before Induction of Labour and Labour Outcome

Summary

Pregnancy and vaginal birth are the main causes of pelvic floor disorders such as urinary incontinence and pelvic organ prolapse. The levator hiatus - the opening in the pelvic floor muscles through which the baby passes - can be measured on three-dimensional transperineal ultrasound at rest, during pelvic floor contraction and during a Valsalva manoeuvre. Its size and its ability to stretch have been related to how long labour lasts and to how the baby is eventually born, but the evidence comes mostly from women in spontaneous labour, in whom the exact time labour began cannot be established.

Women having their labour induced offer a better model, because the time each stage of labour begins is documented. Recently, automated software has made the measurement of the levator hiatus fast and reproducible, which makes it realistic to use in everyday practice.

This prospective observational study will enrol 140 women with a singleton pregnancy at 36 weeks or more who are scheduled for induction of labour. Before induction begins, each woman will have a transperineal ultrasound scan of the pelvic floor at rest, on maximum contraction and on maximum Valsalva. The scan does not involve any vaginal probe, radiation or injection, and takes about 15 minutes. The times of each phase of labour, the way the baby is born and the condition of the perineum after birth will be recorded prospectively from the clinical record. The scan will be repeated before hospital discharge and about one month after birth, together with validated pelvic floor symptom questionnaires.

The main question is whether the area of the levator hiatus measured on Valsalva before induction is related to the duration of the active, pushing phase of the second stage of labour. The study will also examine the duration of the first stage, the mode of delivery, and how the pelvic floor changes in the first month after an induced birth.

Study procedures do not influence clinical care in any way: induction and labour are managed according to standard departmental protocols, and the research ultrasound results are not disclosed to the clinical team.

Conditions

• Labor
• Pelvic Floor Disorder
• Labor Stage, Second
• Induced Labor
• Pelvic Floor
• Levator Ani Muscle Injury

Interventions

DIAGNOSTIC_TEST

Three-dimensional transperineal pelvic floor ultrasound

Transperineal acquisition of 3D/4D pelvic floor volumes at rest, on maximum pelvic floor contraction and on maximum Valsalva manoeuvre, using a transabdominal volumetric probe applied translabially with the woman in the lithotomy position and an empty bladder. Levator hiatal area and diameters are measured offline on the plane of minimal hiatal dimensions using automated segmentation software, with manual tracing as a quality control. No vaginal or rectal probe is used and no ionising radiation is involved. - Other names: TPUS; pelvic floor ultrasound

Sponsors & Collaborators

• University of Roma La Sapienza

  lead OTHER

Principal Investigators

• Giuseppe Rizzo · Università Roma Sapienza

Eligibility

Min Age

18 Years

Sex

FEMALE

Healthy Volunteers

Yes

Timeline & Regulatory

Start

2026-10-01

Primary Completion

2028-10-01

Completion

2028-11-01

Countries

• Italy

Study Locations