Shortly after I learned I was pregnant, I found a new source for medical advice. Not only my obstetrician — though I was lucky enough to find one I liked and trusted — but Google.

Was that just round-ligament pain or a sign of trouble? Better flip open my laptop to find out.

After my son was born, I kept surfing the Web, despite finding a great pediatrician. Is this rash a reaction to a vaccine, or a symptom of a virus? Should I call the doctor?

According to a new report by the Pew Research Center, I’m hardly alone. One in three U.S. adults has gone online to diagnose a medical problem, according to a national telephone survey.

Forty percent of female respondents and 30 percent of males said they’d done this.

Younger adults are more likely than older ones — 47 percent of adults 18 to 29 said they’d turned to the Web for diagnoses, compared with just 13 percent of those 65 and older.

Forty-nine percent of college graduates compared with just 9 percent of people with less than a high school diploma, had consulted the Internet. And 51 percent of adults in households earning $75,000 or more said they’d looked to the Internet for diagnoses, compared with just 25 percent of those earning less than $30,000.

Interestingly, those who consult “Dr. Google” are more likely to have medical insurance than not.

The Pew study made no attempt to determine whether the Internet is good or bad for health care. Local experts say, not surprisingly, that it depends. More knowledge can mean more power for patients. But online queries carry risks of their own.

Scott Safford, a psychologist who works for St. Charles as a behavioral health consultant, says frequent searches can promote what is known as “health anxiety,” or hypochondria. It reminds him of “Medical School Syndrome,” in which doctors-to-be — steeped in stories of rare diseases — suspect that they suffer from every affliction.

In addition to stress, Dr. Richard MacDonell says this can lead to expensive, unnecessary procedures. He says a patient recently demanded an extensive series of blood tests based on something he’d read.

MacDonell owns MyMD, a boutique internal medicine practice that charges an annual fee on top of regular medical costs. Patients get 24-hour cell phone access to MacDonell, longer visits, even house calls. He estimates 80 percent of his patients ask about something they’ve read online.

“It leads to good questions, and it starts a conversation,” he says.

But Safford points out that Web surfers could wrongly conclude that their symptoms aren’t serious.

“Someone who is starting to slur their speech and the muscles in their face have gone slack ... is probably having is a stroke. They need to get to the ER, they don’t need to hop online and Google,” he says.

Doctors are, understandably, defensive that their training can’t be replicated by search engines. But people have long made health decisions at home. In that sense, the Internet is no different from, say, an untrained friend who offers advice.

Online queries do not seem to be replacing doctors’ visits. In fact, 53 percent of those who searched the Web said they followed up with a doctor. Roughly 41 percent of those who found a diagnosis online said their suspicions were confirmed.

Eight out of 10 online health queries start at a search engine such as Google or Bing, while only 13 percent begin at health-specific sites, such as the Mayo Clinic’s.

“Information is only as good as where you get it from and how you use it,” Safford says.

As for me, Dr. Google has its limits. I opted not to download a new app that promised to assess my moles for skin cancer.

As MacDonell puts it: “A computer screen doesn’t know your health history and never went to medical school.”