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Record Id:
Technical update: the role of early comprehensive fetal anatomy ultrasound examination
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Nevo O, Brown R, Glanc P, Lim K
Publication/Review date:
Society of Obstetricians and Gynaecologists of Canada

Bibliographic Source

Journal Citation:
J Obstet Gynaecol Can 2017;39(12):1203-11.
9  Page(s)
SOGC clinical practice guidelines No.352

Subject Information

Diagnostic imaging, Obstetrics and gynecology,
Target Populations:
Fetus, Pregnant or Nursing Mother
Target Gender:
Ultrasonography, Prenatal; Fetus; Pregnancy Trimester, Second; Pregnancy; Fetal Diseases ;

Structured Abstract:

This guideline presents an evidence-based technical update and recommendations for the performance of early comprehensive fetal anatomic scanning (ECFAS) at 11 to 16 weeks' gestation.
Patients at high risk for fetal anomalies and in whom traditional mid–second trimester transabdominal imaging may be challenging or who may benefit from earlier identification of fetal anomalies may be suitable for early fetal anatomy scanning.
Published literature was retrieved through searches of PubMed and Medline in 2016 using key words. Results were restricted to controlled clinical trials, reviews, and observational studies published in English. There were no date restrictions, and searches were updated in the guideline to 2016. Grey (unpublished) literature was identified through searching the websites of health technology assessment and clinical practice guidelines and national and international medical specialty societies. No relevant studies were found.
The quality of evidence in this document was rated using the criteria described in the Report of the Canadian Task Force for Preventive Medicine rating scale (Table 1).
Benefits, Harms, Costs:
It is anticipated that there will be an increase in earlier detection of major fetal anomalies in the target population with the benefits of earlier interventions for those individuals. In areas where the service is not available the patient may need to travel to a nearby centre. Early fetal anatomy scanning is considered to be safe and is not expected to cause a risk to the pregnancy.
Summary Statements
1. Development of fetal organs begins early in the first trimester, with the majority of organs visible by ultrasound evaluation towards the end of the first trimester of pregnancy (High).
2. The majority of significant and sonographically detectable fetal anomalies can be detected on early fetal anatomic ultrasound assessment (High).
3. Early detection of fetal anomalies allows patients to obtain counselling consultations, and genetic testing at an earlier gestational age, as well as more time to consider options for pregnancy management (High).

1. Medical personnel (physicians, technologists, or ultrasound practitioners) who have substantial experience or training in the assessment and interpretation of early comprehensive fetal anatomic scanning should be performing the examination (Strong, High).
2. The examination can be performed transvaginally, transabdominally, or by both approaches, and the choice for each mode depends on the fetal position, the gestational age, and the experience of the operator (Strong, High).
3. Early comprehensive fetal anatomic scanning at 13–16 weeks' gestation should be considered for women who have higher risk for significant fetal anomalies or in whom it is anticipated that a midtrimester transabdominal scan will be technically challenging (High). This scan does not replace the routine 18- to 22-week anatomy scan.
The content and recommendations were drafted and agreed on by the principal authors. The Board of the SOGC approved the final draft for publication. The quality of evidence was rated using the criteria described in the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) methodology framework.


The copyright of this guideline and its companion documents belongs to: Society of Obstetricians and Gynaecologists of Canada

All content is provided for information and education and not as a substitute for the advice of a physician. Joule assumes no responsibility or liability arising from any error or omission or from the use of any information contained herein.

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