A US mother has spoken out to warn other parents after her 7-year-old daughter was killed by one of her own birthday balloons.

Alexandra Hope Kelly of Tennessee enjoyed her seventh birthday party on September 24 and was playing with her birthday balloons a week later when the tragedy occurred.

She asked to pop some of her balloons and her mother Channa Kelly sat with her and watched, aware of the choking risk that deflated latex balloons can pose.

Kelly later went to bed upstairs, leaving little Alexandra playing with a large balloon made of Mylar and shaped like the number seven.

When she awoke later and checked on her daughter, she found her on the floor with the deflated Mylar balloon wrapped around her face.

“My entire world collapsed around me,” Kelly wrote in a heartbreaking message on social media.

She removed the balloon, raced to perform CPR, and called emergency services.

But her daughter could not be revived.

Her grieving family now waits for an autopsy report to determine if their little girl died from helium poisoning or suffocation.

“For her birthday party, I bought a large 34-inch rainbow Mylar number seven balloon inflated with helium, as seen below, along with approximately 10 Roblox-themed latex balloons.

The large birthday balloon that Alexandra was playing with.

“As a parent I was always aware of the choking hazard of latex balloons, but never imagined that there was such a risk regarding these very large Mylar helium-filled balloons. A week after her birthday party, I sat with her as she popped all of her latex balloons,” Kelly wrote.

 “Alex asked if she could pop her large seven balloon and I said that was fine. I went to my bedroom unaware of any dangers with this type of balloon. I fell asleep briefly and when I woke up I found my daughter face down on the living room floor where I had left her.”

Kelly said she first thought her daughter was asleep, before noticing the balloon was around her head.

Channa Kelly (left) said she was speaking up to prevent other families from experiencing her pain.

“I quickly removed the balloon, called 911 and began CPR right away. I asked the 911 operators to remind [me] of the steps of CPR because it had been so long since my last certification and I didn’t want to mess up.

“A police officer arrived and took over CPR, followed by firefighters and paramedics. They worked tirelessly to try to bring her back but their attempts to revive her were unsuccessful. I cried hysterically and was in utter shock and disbelief of what had just occurred, that my daughter and only child was actually gone.”

Saying that her “entire world collapsed”, Kelly said she wanted to share her story to help bring awareness about the dangers of not only latex balloons, but also Mylar balloons.

She said she prayed it would help save other children.

“I wouldn’t want anyone else to experience the pain and devastation that the loss of a child brings.”