Radiologic clinics of North America
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Ultrasound is a valuable diagnostic test throughout the first trimester of pregnancy. Early in this trimester, it is used to distinguish between normal intrauterine, failed intrauterine, and ectopic pregnancies. ⋯ First trimester sonography is also useful for accurate assessment of gestational age. This article reviews these applications, the approach to establishing diagnoses, and ways to avoid diagnostic mistakes that can lead to serious errors in patient management and adverse pregnancy outcome.