Fetal sonograms are commonplace in modern pregnancies and most trust them without question. In scientific literature, however, there is evidence that ultrasound has side effects that could potentially harm fetal development.
More human research is required to assess clinically relevant risks, yet there is a serious obstacle in the way that prevents further study. The only information recorded by sonographers about scan sessions is the number of scans performed. This is not an accurate representation of dose.
Because of this issue, it is virtually impossible for epidemiologists to conclude whether ultrasound is safe or not based on population studies. It is urgent that this obstacle is addressed sooner than later because even if addressed today it would take some years for valid data.