In the 6th month of his wife’s pregnancy, Wall Street Journal writer Kevin Helliker noticed that she underwent 17 fetal ultrasound scans, notwithstanding the fact that she had a low-risk pregnancy.

Curious, Helliker set out researching to find out what doctors generally recommend, how many such scans are medically suggested be given, how many are actually being performed and what is known/not known about ultrasound safety. 

About 80% of most pregnancies are low risk, Helliker discovered, and that not since the early ‘90s has any epidemiological research been conducted on the procedure, and since then the power output on the scanning devices has increased eight-fold.

In his article this summer in the WSJ, Helliker notes that the scans “have turned the images of their unborn into fixtures of social media” and how in 2014, “usage in the U.S. of the most common fetal-ultrasound procedures averaged 5.2 per delivery, up 92 percent from 2004.”

Helliker summarized the potential dangers and risks, also, writing:

A joint statement in May 2014 from several medical societies, including the American College of Obstetricians and Gynecologists, calls for one or two ultrasounds in low-risk, complication-free pregnancies.

Experts in fetal medicine have long recommended women undergo one ultrasound around the 20th week of a low-risk pregnancy, and in recent years they have come to recommend an earlier one as well, around the 12th week. About 80 percent of pregnancies are low-risk.

Fetal ultrasound in humans has never been shown to cause harm. However:

• Nearly all research supporting its safety was conducted using equipment made before 1992, when the procedure produced about one-eighth the acoustic energy than today

• Studies have suggested many operators don’t pay close attention to safety gauges while they are performing procedures.

• Some animal experiments have suggested ill effects of ultrasound on embryos of mice and chickens. 

• A 2006 Yale University study in the Proceedings of the National Academy of Sciences found neurological abnormalities in mice exposed to ultrasound in utero.

• Multiple fetal ultrasounds can raise false alarms, including overestimation of fetal size that can lead to potentially unnecessary c-sections.

• Research suggests multiple scans don’t provide better outcomes in pregnancies.

Continue reading more of the specific, scientifically-grounded advice offerwd on how often US ought to be performed in low risk pregnancies.