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Objective: This guideline reviews the clinical indications for first trimester ultrasound., Outcome: Proven clinical benefit has been reported from first trimester ultrasound., Evidence: A Medline search and bibliography reviews in relevant literature provided the evidence., Values: Content and recommendations were reviewed by the principal authors and the Diagnostic Imaging Committee of the Society of Obstetricians and Gynaecologists of Canada. Levels of evidence were judged as outlined by the Canadian Task Force on Preventive Health Care., (Copyright © 2018 The Society of Obstetricians and Gynaecologists of Canada/La Société des obstétriciens et gynécologues du Canada. Published by Elsevier Inc. All rights reserved.)

Objective: To review the biological effects and safety of obstetric ultrasound., Outcome: Outline the circumstances in which safety may be a concern with obstetric ultrasound., Evidence: The 2005 version of this guideline was used as a basis and updated following a Medline search and review of relevant publications. Sources included guidelines and reports by Health Canada and the American Institute of Ultrasound in Medicine., Values: Review by principal author and the Diagnostic Imaging Committee of the SOGC. The quality of evidence and classification of recommendations have been adapted from the Report of the Canadian Task Force on the Periodic Health Examination., Benefits, Harms, and Costs: Obstetric ultrasound should only be done for medical reasons, and exposure should be kept as low as reasonably achievable because of the potential for tissue heating. Higher energy is of particular concern in the following scenarios: Doppler studies (pulsed, colour, and power), first trimester ultrasound with a long trans-vesical path (>5 cm), second or third trimester exams when bone is in the focal zone, when scanning tissue with minimal perfusion (embryonic), or in patients who are febrile. Operators can minimize risk by limiting dwell time and exposure to critical structures. It is also important to be aware of equipment-generated exposure information., (Copyright © 2018 Society of Obstetricians and Gynaecologists of Canada. Published by Elsevier Inc. All rights reserved.)

Objectives: First, to review normal embryonic development and the sonographic evidence of early pregnancy failure; second, to review sonographic evidence of ectopic pregnancy., Outcomes: First, prediction of pregnancy failure, second, sonographic identification of ectopic pregnancy., Evidence: A MEDLINE search and review of bibliographies in identified articles was conducted., Values: The evidence was reviewed by the Diagnostic Imaging Committee along with the principal authors. A quality of evidence assessment was undertaken as outlined in the report of the Canadian Task Force on the Periodic Health Examination (Table 1)., Benefits, Harms, and Costs: Women presenting with first trimester bleeding may be incorrectly diagnosed with a missed abortion and (or) may be inappropriately reassured about viability. Transvaginal ultrasound provides improved resolution allowing description of early embryonic development characteristics. Improvement in the identification of the sonographic landmark of normal embryonic development and awareness of the sonographic risk factors of pregnancy failure may lead to more successful management strategies. Diagnosis of suspected ectopic pregnancy often involves an assessment of both hormonal markers and sonographic features. Maternal morbidity and mortality can be reduced with an early diagnosis of ectopic pregnancy., Recommendations: There is good (class A) evidence that current ultrasound technology can distinguish between normal and abnormal pregnancies in the first trimester. There is good (class A) evidence that transvaginal ultrasound in conjunction with quantitative-HCG can diagnose ectopic pregnancy.

This document has been archived because it contains outdated information. It should not be consulted for clinical use, but for historical research only. Please visit the journal website for the most recent guidelines.

This document has been archived because it contains outdated information. It should not be consulted for clinical use, but for historical research only. Please visit the journal website for the most recent guidelines.

This document has been archived because it contains outdated information. It should not be consulted for clinical use, but for historical research only. Please visit the journal website for the most recent guidelines.

This document has been archived because it contains outdated information. It should not be consulted for clinical use, but for historical research only. Please visit the journal website for the most recent guidelines.