Is there proof of a connection between early fetal ultrasounds and autism?

Autism symptoms in children could be exacerbated if their mothers undergo fetal ultrasounds early in pregnancy, according to a new study published in Autism Research. And now, the Wall Street Journal reported, doctors are looking for a way to cut back on first-trimester fetal ultrasounds without scaring away women who might need the procedure, while definitive proof of autism-related effects remains elusive.

The study looked at more than 2,600 families who have kids with autism and analyzed the mothers’ own descriptions of their fetal ultrasounds. The study authors raised concerns about the heat and force exerted upon the fetuses and whether or not this could be harmful to them. The researchers said it might be better to avoid first-trimester ultrasounds unless there’s a medically necessary reason.

Incidence of first-trimester ultrasounds have been on the rise, according to the Journal. From 2004 to 2014, use of fetal ultrasounds increased 92 percent to more than five times per pregnancy, many of which were “clearly low-risk,” according to one study.

But many experts say this ultrasounds-autism link is shaky at best, especially since this particular study relied on parental memory and not medical records. And there could be benefits to early fetal ultrasounds besides medically monitoring the pregnancy—some parents are interested in seeing an image of their baby as soon as possible.

Still, much of what physicians know about fetal ultrasounds are based on equipment that’s 25 years old and doesn’t lead to obvious conclusions. Check out the Wall Street Journal to see how today’s equipment differs from that and how often doctors say normal pregnancies should be examined using the technology.