Kylie Kelce Breaks Down In Tears Over Past Miscarriage, Found Out On Jason's Birthday

Kylie Kelce is providing heartbreaking details on her 2018 miscarriage ... revealing she learned the news on Jason's birthday.

The Philadelphia Eagles legend's wife opened up on the tragic experience on her "Not Gonna Lie" podcast this week ... explaining she wanted to share her story in honor of October being Pregnancy and Infant Loss Awareness Month.

Kylie said right before her 12-week appointment, the couple decided to tell Ed and Donna about the baby on the way during a trip to London for Jason's game with the Eagles ... and went on to alert Travis and other family members.

But once she was back on U.S. soil and at her next appointment, Kylie said a nurse couldn't find a heartbeat ... and she knew what happened.

"They estimated that the baby had stopped developing between, I believe it was nine and 10 weeks," Kylie said. "Essentially, I had had what you would refer to as a missed miscarriage. It means that your body did not realize that the pregnancy was no longer viable."

"It was a s****y day because it was Jason's birthday," she continued as she fought back tears. "I called my mom and told her that I couldn't tell Jason because it was his birthday, which seems very silly."

"It seems very silly because obviously I'm going to tell my husband what happened. And I did. And it was hard for both of us."

Kylie and Jason have since welcomed four girls to the world ... and she admitted her past experience "messed with my brain" -- and the loss still hurts.