"Spy Kids" actor Alexa PenaVega and her husband, "Big Time Rush" actor Carlos PenaVega, announced on Monday that their daughter was delivered as a stillborn. Their daughter, whom they named Indy Rex PenaVega, was the couple's fourth child. 

"There are never the right words to say when it comes to loss," the couple said in a joint statement on Instagram. "After a beautiful and peaceful delivery our daughter 'Indy' was born at rest. It has been a painful journey. But in the pain we have found peace." 

Alexa PenaVega posted a pregnancy vlog from the hospital on March 18, saying she had been there for five days after she started bleeding.

"My history with this pregnancy has not been easy," she said, saying that at one point, she thought her water had broken and that she couldn't get the baby to move, despite her usually being active. The baby eventually started moving on the way to the hospital, she said. 

"It looks like I've had basically a separation of my placenta from my uterus, not completely, a partial," she said. "Luckily, it's come to a place where it can be maintained."

According to the CDC, roughly 21,000 babies are delivered as stillbirths every year in the U.S. – about the same number of babies that die during the first year of life. The rate of early stillbirth has remained about the same over time, the agency says, while the rate of late and term stillbirths has "dramatically reduced."

The PenaVegas did not release details about the birth. They said that Indy "already changed our lives in so many ways." They announced their pregnancy in November. 

"She was absolutely beautiful. And looked just like daddy. Dark hair and all," the couple said. "Grief has come to us in waves. Moments of feeling absolutely gutted... then moments of feeling blessed by just getting a moment with her." 

"Indy Rex PenaVega, you completely changed our world," they ended their statement. "You moved us to a new place. You gave us the community we have been longing for. We love you can't wait to see how many other lives you change." 

Former co-stars have showered the couple with condolences for their loss. 

"Our thoughts and prayers are with your whole family," Big Time Rush commented on their Instagram post. "We love you and you're in our hearts always. Rest in peace, sweet angel." 

Tiffany Thornton, known for her roles in Disney's "Sonny with a Chance" and "So Random!" said she has "no words." 

"I am broken hearted from you guys and can't even fathom the loss of a tiny babe," she said. "I'm praying she will send signs to y'all from Heaven daily. Loving y'all from Arkansas and praying fervently for your sweet family."

In:
• Disney
• Nickelodeon
• Pregnancy

Li Cohen is a social media producer and trending content writer for CBS News.