Left: Trans-abdominal curvilinear probe

Right: Trans-abdominal linear probe

Pearl: Use the linear array probe to obtain a higher resolution image (due to the higher frequency) and obtain a clear picture of the yolk sac in early 1st trimester pregnancy if initial attempt with the curvilinear probe fails. However, this will not always work in women with high body mass index due to the decreased tissue penetration of the linear probe.

Resources

Linear probe in early pregnancy. 5 Minute Sono Blog. Available at http://blog.5minsono.com/linear_preggers/.

Tabbut, M, Harper D, Jones R. High frequency linear transducer improves detection of an intrauterine pregnancy in first-trimester ultrasonography. The American Journal of Emergency Medicine. 2016;34(2)288-291.