Heart Failure Patient Was Told Pregnancy Wasn't an Option. Then Best Friend Offered to Be Her Surrogate (Exclusive)

“She's given us something that words can never, ever describe," Natalie Dart, whose daughter turns 1 this month, tells PEOPLE of friend Kalan Collard

• When Natalie Dart and her husband wanted to start a family, her physician warned her that due to her health, pregnancy could be life-threatening

• For Dart's best friend, volunteering to be the couple's surrogate was an easy decision

• "There aren't many people in my life that I would do it for, but Natalie is my person," Kalan Collard tells PEOPLE

After Natalie Dart was first diagnosed with heart failure, she could never have imagined being the mother of a healthy — and sassy — toddler. Now, thanks to her best friend since childhood, who stepped up to be her surrogate, her baby is about to turn 1.

“Growing up together, we joked that if we couldn't have kids, we would carry each other's,” says Dart, now a 35-year-old nurse living in Indianapolis. “And she wasn't kidding.”

"There aren't many people in my life that I would do it for," adds Collard, "but Natalie is my person.”

On the morning of Dec. 5, 2011, when she was still a student at Eastern Illinois University, Dart experienced trouble breathing and vomited blood in her apartment. Collard, who was staying over at Dart’s place, immediately took her friend to the hospital.

“The impending doom feeling of flash pulmonary edema is horrific,” Dart tells PEOPLE. “I would never wish it upon someone."

Dart, then 22, was told she had heart failure — and after being transferred to a different hospital, she was diagnosed with ischemic cardiomyopathy, which occurs when the heart fails to pump blood properly. When doctors there couldn’t figure out how to fix the issue, they recommended that she visit the Cleveland Clinic in Ohio.

Related: Utah Grandma, 56, Serving as Surrogate for Son Whose Wife Had a Hysterectomy: 'Most Beautiful Thing'

There, Dr. Eileen Hsich put Dart on a drug regimen to lower her heart rate, which Dart says, "gave my body the time and energy it needed to heal."

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Years later, Natalie married her high school sweetheart in 2014. But when she visited Hsich the following year to get her approval to start trying to have a baby, the physician told her that physically carrying a baby with her heart condition could endanger her life.

"[She] would have had a high risk of death if she attempted pregnancy," Hsich tells PEOPLE, noting that medication to help her condition could have also resulted in birth defects.

Although it was a tough pill to swallow, the couple did their diligence with examining all their options.

"We explored adoption, fostering and foster to adoption options," she says. They later settled on gestational surrogacy, in which the embryo from the intended parents is transferred to the uterus of the carrier.

For Collard, now 34, it was a no-brainer to volunteer to be the couple's surrogate.

Related: 4 Surrogates Share Why They Carried Babies for Other Families — and Whether They'd Do It Again

“I don't even think I thought about it," Collard says. "I didn't even have my own children yet, but I knew I wanted to do it for her.”

Still, the journey to becoming their surrogate ended up taking a number of years, during which time Collard welcomed two children of her own — and Dart experienced another bout of heart failure. Fortunately, thanks to a game-changing medication, her heart is now doing better than ever.

After an earlier attempt, the transfer was successfully carried out in August 2022. And on April 19, 2023, baby Monroe was born at 6 lbs, 13 oz.

“To watch your child be born is something that I will never forget," says Dart. "I was the stoic one, and my husband was the one crying. It's a huge moment, getting to see her sweet little face.”

Related: Mom Forced to Adopt Her Biological Twins ‘Almost at the Finish Line’ in Getting Surrogacy Laws Changed (Exclusive)

Almost a year after her birth, Monroe is doing well, Dart says. “I could not be more thrilled that she's here with us," she says, joking, "Each day I'm just like, ‘Man, the clutter in my house is worth it.’ ”

“It’s pretty amazing given what she went through,” adds her doctor. “Natalie is a special person. She is a very caring person, so [it's] not surprising she has amazing friends who love her and would do something this special for her to enable her to enjoy her dreams."

Collard, who lives in Monticello, Indiana, says that her kids — two stepdaughters, 19 and 11, as well as a 6-year-old son and a 5-year-old daughter — adore Monroe to pieces.

“Monroe doesn't know it, but she has built-in best friends,” Collard says.

Dart gets a little emotional when asked about Collard’s selfless gesture to become her surrogate.

“She's given us something that words can never, ever describe," Dart says. "She gave us our world. Monroe is our world, and Kalan gave us the opportunity to bring her here. The gift that she was able to give us is indescribable. And I wish and pray that every person in this world could have a friend like her. I'm just counting my blessings that I am the one that got to have her.”

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