US in pregnancy

Q: Ultrasound (US) should be used with caution in febrile pregnant patients?

A) True

B) False

Answer: A

Although in general US is considered safe in pregnancy, this statement comes with a few caveats. The harm from US is mostly in regards to temperature rise around the tissues. B and M-mode imagings have acoustic outputs without much harmful temperature rise, but spectral and color Doppler US equipment has greater time-averaged intensities and may produce biologically significant temperature rise. The use of fetal Doppler in the first trimester may have a potential effect on organogenesis. Spectral Doppler, color flow imaging, power imaging, and other Doppler ultrasound modalities should generally not be used unless absolutely necessary in the embryonic period at least up to 10 weeks of gestation. 

In this regard extra care is needed for a pregnant patient who is febrile.

#ob-gyn

#radiology

References:

1. American Institute of Ultrasound in Medicine. AIUM practice guideline for the performance of obstetric ultrasound examinations. J Ultrasound Med 2013; 32:1083.

2. Sheiner E, Shoham-Vardi I, Abramowicz JS. What do clinical users know regarding safety of ultrasound during pregnancy? J Ultrasound Med 2007; 26:319.

3. Salvesen K, Abramowicz J, Ter Haar G, et al. ISUOG statement on the safe use of Doppler for fetal ultrasound examination in the first 13 + 6 weeks of pregnancy (updated). Ultrasound Obstet Gynecol 2021; 57:1020.

4. Bhide A, Acharya G, Baschat A, et al. ISUOG Practice Guidelines (updated): use of Doppler velocimetry in obstetrics. Ultrasound Obstet Gynecol 2021; 58:331.

5. Bly S, Van den Hof MC, Diagnostic Imaging Committee, Society of Obstetricians and Gynaecologists of Canada. Obstetric ultrasound biological effects and safety. J Obstet Gynaecol Can 2005; 27:572.

6. Abramowicz JS. Fetal Doppler: how to keep it safe? Clin Obstet Gynecol 2010; 53:842.