In Vivo Assessment of the Elastic Properties of Women's Pelvic Floor During Pregnancy

Study Overview
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Brief Summary
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The investigators hypothesize that optimize our risk prediction for pelvic floor disorders after childbirth by taking into account intrinsic women's pelvic floor characteristics and their changes during pregnancy. Shear Wave Elastography (SWE) is a new technology that allowed an in vivo assessment of elastic properties of tissues. The main endpoint of this study is to describe biomechanical changes that occurs into women's pelvic floor during pregnancy using SWE technology. An ancillary study will investigate the reproducibility of the assessement of the viscoelastic properties of the levator ani muscle, the biceps brachii muscle and the gastrocnemius medialis muscle using shear wave elastography in a nulliparous non-pregnant women cohort

Detailed Description
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Each woman included in the princeps study undergo 3 visits during pregnancy (14-18 weeks, 24-28 weeks and 34-38 weeks). Each visit contain a clinical pelvic floor assessment (POP-Q), an ultrasound pelvic floor assessment, an ultrasound pelvic floor muscles (levator ani and external anal sphincter) viscoelastic properties assessment using shear wave elastography and an ultrasound peripheral muscles (biceps brachii and gastrocnemius medialis) using shear wave elastography. The main objective is to describe changes in viscoelastic properties of pelvic floor muscles during pregnancy. Secondary objectives are to compare muscular behavior of pelvic floor muscles and peripheral muscles during pregnancy. Data about the delivery are also collected in order to analyse preliminary data about the hypothetic association between viscoelastic properties of women's pelvic floor and both mode of delivery and perineal trauma at childbirth. An ancillary study involve non-pregnant nulliparous women in oder the investigate the reproducibility of shear wave elastography assessment of the levator ani muscle. Secondary objective is to investigate this reproducibility for biceps brachii and gastrocnemius medialis muscles.

Official Title
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In Vivo Assessment of the Elastic Properties of Women's Pelvic Floor During Pregnancy

Conditions
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Pregnancy

Intervention / Treatment
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* Other: Perineal ultrasound assessment
* Other: Peripheral muscles assessment
* Other: Clinical pelvic floor assessment


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Nulliparous pregnant women Age >18 years Normal pregnancy BMI < 35 Kg.m-2 Without previous pelvic floor disorders Without muscular diseases, psychiatric diseases Exclusion Criteria: Parous women Previous pelvic floor disorders BMI > 35 Kg.m-2 Age < 18 years Psychiatric diseases, muscular diseases Pathological pregnancy For the ancillary study about the reproducibility on non-pregnant women Inclusion Criteria: Non pregnant women Age >18 years BMI < 35 Kg.m-2 Without previous pelvic floor disorders Without muscular diseases, psychiatric diseases Exclusion Criteria: Parous women Previous pelvic floor disorders BMI > 35 Kg.m-2 Age < 18 years Psychiatric diseases, muscular diseases

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 50 Years

Sexes Eligible for Study
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Female

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Diagnostic
Intervention Model: Single Group Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: pregnant women<br>pregnant women with one visit per trimester of pregnancy (14-18 weeks, 24-28 weeks and 34-38 weeks) For the ancillary study: non-pregnant nulliparous women | Other: Perineal ultrasound assessment<br>* women were assessed in lithotomy position with an empty bladder at rest, perineal contraction and Valsalva maneuver using a linear translabial probe. We measure the distance between symphysis and ano-rectal angle. In the same position we investigate the levator ani viscoelastic properties using shear wave elastography at rest, Valsalva maneuver and maximal contraction. During the same examination, we assess the viscoelastic properties of the external anal sphincter using shear wave elastography for the 3 conditions: rest, Valsalva, contraction. This pelvic floor muscles assessment is performed for each of the three planned visits For the ancillary study on non pregnant women: viscoelastic properties of levator ani are assessed at rest, stretch and contraction using shear wave elastography. This pelvic floor muscle assessment is performed for each of the two planned visit in the ancillary study.<br>Other: Peripheral muscles assessment<br>* The visco elastic properties of the biceps brachii muscle and the gastrocnemius medialis muscle are assessed rest, stretch and maximal contraction using shear wave elastography. This peripheral muscle assessment is perform for each of the three planned visits. For the ancillary study on non pregnant women: viscoelastic properties of biceps brachii and gastrocnemius medialis muscles are assessed at rest, stretch and contraction using shear wave elastography. This peripheral muscles ultrasound assessment is performed for each of the two planned visit in the ancillary study.<br>Other: Clinical pelvic floor assessment<br>* Women undergo a pelvic floor assessment using the Pelvic organ prolapse quantification system. Such an assessment is performed for each of the three planned visits. Women included in the ancillary study are not involved with this examination<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Quantify elastic properties of pregnant women pelvic floor muscles and their changes during pregnancy | Shear wave modulus value measured for each muscles across the pregnancy. | 14-18 weeks | 
| Quantify elastic properties of pregnant women pelvic floor muscles and their changes during pregnancy | Shear wave modulus value measured for each muscles across the pregnancy. | 24-28 weeks | 
| Quantify elastic properties of pregnant women pelvic floor muscles and their changes during pregnancy | Shear wave modulus value measured for each muscles across the pregnancy. | 34-38 weeks | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Look for an association between shear modulus assessed for pelvic floor muscles and perineal distension assessed by clinical and ultrasound assessment | Association between the shear modulus assessed for pelvic floor muscles and both clinical (POP-Q) and ultrasound pelvic floor distension. | 14-18 weeks | 
| Look for an association between shear modulus assessed for pelvic floor muscles and perineal distension assessed by clinical and ultrasound assessment | Association between the shear modulus assessed for pelvic floor muscles and both clinical (POP-Q) and ultrasound pelvic floor distension. | 24-28 weeks | 
| Look for an association between shear modulus assessed for pelvic floor muscles and perineal distension assessed by clinical and ultrasound assessment | Association between the shear modulus assessed for pelvic floor muscles and both clinical (POP-Q) and ultrasound pelvic floor distension. | 34-38 weeks | 
| Look for an association between changes in elastic properties of pelvic floor muscles and peripheral muscles (biceps brachii and gastrocnemius medialis). | Association between shear modulus changes assessed for pelvic floor muscles (levator ani and/or external anal sphincter) and shear modulus changes assessed for peripheral muscles (biceps brachii or gastrocnemius medialis) | 14-18 weeks | 
| Look for an association between changes in elastic properties of pelvic floor muscles and peripheral muscles (biceps brachii and gastrocnemius medialis). | Association between the shear modulus changes assessed for pelvic floor muscles (levator ani and/or external anal sphincter) and shear modulus changes assessed for peripheral muscles (biceps brachii or gastrocnemius medialis) | 24-28 weeks | 
| Look for an association between changes in elastic properties of pelvic floor muscles and peripheral muscles (biceps brachii and gastrocnemius medialis). | Association between the shear modulus changes assessed for pelvic floor muscles (levator ani and/or external anal sphincter) and shear modulus changes assessed for peripheral muscles (biceps brachii or gastrocnemius medialis) | 34-38 weeks | 
| To assess the feasibility of measuring the viscoelastic properties of the external anal sphincter using shear wave elastography | Number of success procedures for each visit and each condition | 14-18 then 24-28 then 34-38 weeks | 
| Quantify elastic properties of pregnant women external anal sphincter and their changes during pregnancy | shear modulus of the external anal sphincter | 14-18 then 24-28 then 34-38 weeks | 
| Investigate if pelvic floor muscle's shear modulus (viscoelastic properties) and their changes during pregnancy are associated with both : the mode of delivery (spontaneous, instrumental, cesarean) and perineal tears occurrence. | Association between the mode of delivery (spontaneous, instrumental or cesarean), the perineal trauma (perineal tears occurrence) and the shear modulus of pelvic floor muscles and their changes during pregnancy | Shear modulus measurements (14-18 then 24-28 then 34-38 weeks) and the delivery |