Are color and pulsed Doppler sonography safe in early pregnancy?

Diagnostic ultrasound has been used for many years with a remarkable history of safety during the standard clinical practice. Introduction of color and pulsed Doppler modes resulted with higher levels of transmitted and absorbed ultrasonic energy. This fact raised the question for the safety of its use in early pregnancy. This article presents the pros and contras regarding the safety and summarized actual guidelines and safety limits suggested and prescribed by several instances that supervise the use of ultrasound in medicine (WFUMB, ECMUS, ECURS, AIUM/NEMA). In addition, different clinical and experimental applications of Doppler ultrasound in early pregnancy are discussed regarding the safety limits. Generally, there are no strictly defined limits for the use of Doppler ultrasound in the early pregnancy. However, there is an unequivocal demand for carefulness that is best expressed by the ALARA principle. The prudent use of Doppler takes into account benefits against the possible theoretical risks, rather than prohibiting clinically useful technology or applications.