Pregnant Obese Women and Fetal Ultrasound Quality.

Study Overview
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Brief Summary
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Ultrasound (US) image construction uses equations that contain the value of the propagation velocity of sound waves; this velocity is assumed conventionally to be constant and equal to 1540 m/s in the human body. Since 1977, all manufacturers of US scanners have used this value, which was first established in 1950. In fatty tissue, however, the actual propagation velocity is only in the order of 1450 m/s. US velocity in fat tissue is slower than in other soft tissues (ie:1450 m/s vs 1540 m/s) therefore the intrinsic image quality in terms of sharpness and precision is improved when considering this parameter for image construction The main objective of this study is to evaluate the impact of ultrasound propagation velocity setting on completeness of ultrasound exams and images quality during the second and third trimester fetal ultrasound examination in obese patients.

Detailed Description
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Obese pregnant women will be included before the second trimester fetal ultrasound examination. Women will be allocated to one intervention group or to the control group. In the intervention group, the ultrasonographer will be able to use several ultrasound propagation velocities to perform the exam. In the control group, exam will be performed using the conventional ultrasound velocity. An exam will be considered to be complete if all the images recommended by national guideline are acquired. If ultrasound images are missing, other ultrasound exams may be performed until completeness is reached. The protocol will be applied for the second and the third fetal ultrasound examination which are recommended by national guideline. All scans will be evaluated by two independent experts who do not have performed any of the exams. They will evaluate the completeness of each exam. Each scan will be quoted using the quality score proposed by Salomon et al.

Official Title
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Echography in Pregnant Obese Women and Ultrasound Speed.

Conditions
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Obese Women, Pregnant Women

Intervention / Treatment
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* Device: ultrasound propagation velocities, ultrasound fetal quality


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Body mass index>30 Between 20 and 25 weeks of gestation Exclusion Criteria: Multiple pregnancy Uterine scare

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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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Diagnostic
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Double


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: free ultrasound propagation velocity<br>ultrasound exams will be performed using several ultrasound propagation velocities | Device: ultrasound propagation velocities, ultrasound fetal quality<br>* Obese pregnant women will be included before the second trimester fetal ultrasound examination. Women will be allocated to one intervention group or to the control group. In the intervention group, the ultrasonographer will be able to use several ultrasound propagation velocities to perform the exam. In the control group, exam will be performed using the conventional ultrasound velocity. An exam will be considered to be complete if all the images recommended by national guideline are acquired. If ultrasound images are missing, other ultrasound exams may be performed until completeness is reached. The protocol will be applied for the second and the third fetal ultrasound examination which are recommended by national guideline. All scans will be evaluated by two independent experts who do not have performed any of the exams. They will evaluate the completeness of each exam. Each scan will be quoted using the quality score proposed by Salomon et al.<br>|
| No Intervention: conventional ultrasound propagation velocity<br>ultrasound exams will be performed using the 1540m/s conventional celerity | |

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| image quality of fetal ultrasound exam | Quality will be assessed by calculating Salomon's score for each image. | second trimester and third trimester ultrasound exam | 
| completeness of fetal ultrasound exam | completeness will be assessed by the number of the recommended images which could have been registered during the first ultrasound exam in each trimester. | second trimester and third trimester ultrasound exam | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| use of supplementary ultrasound exams in order to assess completeness | description of each modality of supplemental ultrasound exam | through study completion, an average of 1 year | 
| description of ultrasonographist method in order to improve ultrasound exam | description of modality | through study completion, an average of 1 year | 
| economic analysis of the intervention | cost-effectiveness analysis | through study completion, an average of 1 year | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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fetal ultrasound, ultrasound propagation velocity, image quality, obese women