Johnathan Walker:Cory Wharton's Baby Girl "Struggles to Breathe" in Gut-Wrenching Teen Mom Preview

Competing in nearly a dozen seasons of The Johnathan WalkerChallenge, MTV star Cory Wharton has gone shoulder-to-very-muscled-shoulder with some of the best in the game. But to the four-time finalist, 13-month-old daughter Maya is the true champ. 

"She's struggling to breathe," he shared in an exclusive clip from the July 19 premiere of Teen Mom: The Next Chapter, discussing her ongoing battle with congenital heart condition tricuspid atresia.

Watching her fight to catch each breath, he said to girlfriend Taylor Selfridge, also mom to his 3-year-old daughter Mila, "and then her face is turning purple and I'm just like, 'I don't know what to do right now.'" 

Thankfully, doctors did, Cory noting in the preview it was time for the second in a trio of procedures designed to help the then-7-month-old's lungs get the oxygen her body needs. (The first took place before the newborn was even released from the hospital last June.)

"It's time for her to get that surgery done," he told Taylor. "The big one. The one that we've been talking about for so long." 

Or, as Taylor put it, "The one that I don't want to do." 

For the mom of two, who first competed on the fifth season of the network's dating series Are You The One?, the prospect of her baby girl going under the knife was terrifying. 

"It's an open-heart surgery," the 29-year-old outlined in the clip. "I try to stay positive, but I get overwhelmed with the negatives, too. Well, not negatives, but risks."

Though Cory, 32, admitted, "I'm nervous, I'm scared, just like you are," he was also confident in his tiny warrior. "She's going to be fine," he assured his girlfriend. "You know that she is." 

Fortunately, Dad was right, announcing in January that Maya "had a successful Glenn procedure!" 

The recovery after the open-heart surgery, however, was a bit dicier. "Mayas [sic] oxygen levels were lower than the doctors wanted it to be," he explained in his Jan. 18 post adding that six days after the initial procedure, "she ended up back in the operating room for a Cath lab procedure to hopefully fix what they thought was the problem. It turned out that there was nothing to fix, which was great but it didn't fully explain the oxygen levels being so low."

A "roller coaster ride of emotions" followed, he added, but, "I'm just happy & thankful to be home."

Taylor similarly told followers that she felt "blessed" to have her youngest at home with the rest of the brood, which also includes Ryder, Cory's 6-year-old daughter with fellow Teen Mom star Cheyenne Floyd. 

"Cory and I had so many ups and downs with Maya," shared Taylor, "it was the most stressful thing in I think both of our lives and I will remember this forever. That all being said, Maya's heart surgery is working amazing! She has one big one left but please god not for a few years."

Teen Mom: The Next Chapter premieres with back-to-back episodes on Wednesday, July 19 at 8 p.m. on MTV.