Ultrasound Estimation of Fetal Macrosomia at Term: Diagnostic Accuracy Within 24 Hours of Delivery (ECHO-MACRO)

ECHO-MACRO : Ultrasound Estimation of Fetal Macrosomia at Term: Diagnostic Accuracy Within 24 Hours of Delivery

Obstetric ultrasonography is now an essential tool for monitoring pregnancy. In France, three ultrasounds are recommended during a singleton pregnancy (at 12, 22, and 32 weeks of amenorrhea) to improve maternal and neonatal care. Among the parameters studied, fetal weight estimation allows for the assessment of fetal growth and the detection of certain conditions such as intrauterine growth restriction or macrosomia.

Fetal weight estimation is based primarily on the Hadlock formula, which combines several biometric measurements (head circumference, abdominal circumference, and femur length). This estimate has a margin of error of 6 to 10% compared to birth weight, which is still accurate enough to guide important medical decisions, such as inducing labor or performing a cesarean section. However, an estimation error can have negative consequences for both mother and child.

Fetal macrosomia is defined as a birth weight greater than or equal to 4000 g. It affects approximately 5 to 10% of pregnancies. Screening is mainly based on ultrasound, particularly in the second and third trimesters.

Macrosomia is associated with an increased risk of complications for the mother (cesarean section, postpartum hemorrhage, or deep vein thrombosis) and the child (shoulder dystocia, fractures, brachial plexus palsy, or neonatal asphyxia). These risks are increased in cases of macrosomia in the context of maternal diabetes.

Within the gynecology-obstetrics department, physicians use the protocole of macrosomia screening described in the DAME trial. If macrosomia is suspected an additional ultrasound is performed at around 36 weeks of amenorrhea. The Hadlock formula is used to estimate fetal weight. The ultrasound criteria for suspecting macrosomia are an estimated fetal weight above the 95th percentile (90th percentile in cases of maternal diabetes) according to WHO curves. In these cases, induction is offered between 38 and 39 weeks of amenorrhea, if the cervix is favorable. A cesarean section is offered to the patient if the estimated fetal weight is greater than 5000 g in the absence of diabetes and greater than 4500 g in cases of associated diabetes.

Nevertheless, the probability of a child being born macrosomic after ultrasound suspicion is between 17% and 80% on average, and 53% in our center. Although beneficial in the context of macrosomia, the effects of induced labor or cesarean delivery are not insignificant for the mother and her baby. In this context, the value of this study is to demonstrate that performing an ultrasound as close to the birth as possible could allow for a more reliable estimation of fetal weight and better detection of macrosomia in order to avoid unnecessary procedures.

The investigators hypothesize that fetal weight estimation is more accurate when performed within 24 hours prior to delivery. When the assessment is conducted earlier, it inherently assumes a constant fetal growth rate until birth, which may not reflect actual growth patterns. A more precise estimation of birth weight could improve clinical decision-making and optimize maternal and neonatal care, potentially reducing unnecessary interventions such as labor induction or cesarean delivery.

Study Overview

Status

Not yet recruiting

Conditions

Intervention / Treatment

Study Type

Interventional

Enrollment (Estimated)

285

Phase

  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Study Locations

      • Avignon, France, 84000
        • Centre Hospitalier d'Avignon, Hôpital Henri Duffaut
        • Contact:
        • Principal Investigator:
          • Jean-Yves Col, MD
        • Sub-Investigator:
          • Sonia Rasolofomanana, MD

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

  • Adult
  • Older Adult

Accepts Healthy Volunteers

Yes

Description

Inclusion Criteria:

  • Age ≥ 18 years old.
  • Patient with suspected fetal macrosomia above the 95th percentile, or above the 90th percentile in the case of maternal diabetes, according to Hadlock's formula and WHO charts, during the third-trimester ultrasound (between 32 and 34 weeks of amenorrhea).
  • Female patient presenting for a follow-up ultrasound at 36 ± 1 weeks of amenorrhea due to suspected macrosomia.
  • Singleton pregnancy.

Exclusion Criteria:

  • Fetal weight estimation at 36 ± 1 weeks of amenorrhea and macrosomia assessment performed outside of the hospital.
  • Patient with uncertain gestational age.
  • Patient with a multiple pregnancy
  • Presence of detectable morphological or chromosomal abnormalities.

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Diagnostic
  • Allocation: Non-Randomized
  • Interventional Model: Parallel Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Experimental: Group 1
Macrosomia confirmed by ultrasound at 36 weeks
Ultrasound estimation of fetal macrosomia at 12 weeks of amenorrhea (estimated weight according to the Hadlock formula and WHO growth charts)
Ultrasound estimation of fetal macrosomia at 22 weeks of amenorrhea (estimated weight according to the Hadlock formula and WHO growth charts)
Ultrasound estimation of fetal macrosomia at 32 weeks of amenorrhea (estimated weight according to the Hadlock formula and WHO growth charts)
Ultrasound estimation of fetal macrosomia within 24 hours ± 6 hours, prior to birth (estimated weight according to the Hadlock formula and WHO growth charts)
Other: Group 2
Macrosomia not confirmed by ultrasound
Ultrasound estimation of fetal macrosomia at 12 weeks of amenorrhea (estimated weight according to the Hadlock formula and WHO growth charts)
Ultrasound estimation of fetal macrosomia at 22 weeks of amenorrhea (estimated weight according to the Hadlock formula and WHO growth charts)
Ultrasound estimation of fetal macrosomia at 32 weeks of amenorrhea (estimated weight according to the Hadlock formula and WHO growth charts)

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Frequency of fetal macrosomia
Time Frame: 24 hours before birth
Frequency will be expressed as numbers and percentages
24 hours before birth

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Assess the diagnostic performance of the different ultrasound examinations for the detection of fetal macrosomia at birth.
Time Frame: At birth
By analyzing true-positive, false-positive, true-negative, and false-negative rates in a 2x2 contigency table
At birth

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Estimated)

March 1, 2026

Primary Completion (Estimated)

March 1, 2028

Study Completion (Estimated)

September 1, 2028

Study Registration Dates

First Submitted

February 19, 2026

First Submitted That Met QC Criteria

February 19, 2026

First Posted (Actual)

February 25, 2026

Study Record Updates

Last Update Posted (Actual)

March 4, 2026

Last Update Submitted That Met QC Criteria

March 2, 2026

Last Verified

March 1, 2026

More Information

Terms related to this study

Other Study ID Numbers

  • ECHO-MACRO

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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