Dr. Mary Dillhoff was no stranger to deep vein thrombosis.

As a surgical oncologist at The Ohio State University Wexner Medical Center, she had seen the potentially dangerous dozens of time in her cancer patients.

Yet, even Dillhoff didn’t recognize the early warning signals when the clot known as DVT first formed in her leg while she was eight months pregnant.

It wasn’t until her leg swelled up and turned blue last December that Dillhoff finally sought out the medical help she needed to get rid of the lurking clot in her vein.

Dillhoff’s case not only points out the importance of recognizing the symptoms of DVT but also how common the ailment is in pregnant women.

“I had chalked it up to being pregnant,” Dillhoff told Healthline. “I think a lot of pregnant women will discount the symptoms.”

Read more: Get the facts on deep vein thrombosis »

A common blood clot

Deep vein thrombosis (DVT) strikes almost a year in the United States, according to the Centers for Disease Control and Prevention (CDC).

Clots from DVT kill an estimated 60,000 to 100,000 Americans per year. Up to 30 percent of them will die within one month of diagnosis.

According to a , the risk of DVT is four to five times higher in pregnant women than the general population.

Dr. Mounir Haurani is familiar with these statistics.

He’s a vascular surgeon at the Wexner Medical Center. He was also the lead surgeon in Dillhoff’s procedure in December.

Haurani told Healthline that the medical understanding of DVT is much deeper now than it was in the 1990s.

“However, it’s still a challenging diagnosis,” he said.

Haurani said pregnant women should not assume that symptoms like leg swelling and shortness of breath are due to pregnancy.

“I don’t want them to brush it off,” he said. “This is something that is preventable.”

He added this is particularly true for younger women who are in good shape.

“These are young, healthy women. Something like this is the farthest thing from their mind,” Haurani said.

He advised pregnant women to stay active as long as possible during their pregnancies. He also urged them to employ compression and elevation on their legs.

Read more: Maintaining a healthy pregnancy »

A quick solution

Dillhoff was one of those young, healthy pregnant women.

She had run a 5K race a couple weeks earlier in December and felt she was in good shape as she entered the final weeks of pregnancy.

She dismissed the shortness of breath, but immediately sought assistance when one of her legs swelled up and turned blue while the other leg didn’t.

“There was no question in my mind then what this was,” she recalled.

On Dec. 30, Dillhoff gave birth to her second child.

A few days later, on Jan. 4, she was given clot-busting medication that made her leg drastically better.

The following day, she underwent surgery to have a stent placed near her hip.

Dillhoff noted that once the DVT was diagnosed, it was a relatively quick and easy to treat.

She advised pregnant women to look for any sudden changes in their health, especially in the later stages of their pregnancies.

In particular, take seriously any symptoms like shortness of breath or swelling in only one leg.

“When you’re pregnant, it’s easy to ignore the symptoms,” she said.