Jessica Abma, from the US, explained her daughter suffered severe heatstroke, despite not even being out in the sun, because her room was so hot.
The mum’s warning has been shared by nearly 50,000 people in two weeks since it was posted on 14 July.
“I expected a lot of horrible things to be said - and some have been - but I got far more that we’re thankful for,” Abma told HuffPost UK.
“Despite at first thinking I would be judged I’m glad I shared in the hope it will help another family.”
Abma shared a photo of her daughter on Facebook and called it the “scariest moment” she has ever had to experience.
Abma said her daughter, Anastasia, had taken herself off for a nap and she had no idea how hot the bedroom was until she went to wake her up.
She said Anastasia was soaked in sweat and had a red face.
“This is severe heatstroke,” Abma wrote on Facebook. “There is nothing scarier than not being able to wake your baby up. This is clear proof a child doesn’t need to be in the sun to get heat stroke.
“It took us 20 minutes to wake her up, when ambulance came, they came with investigators because they didn’t know what to expect, as did I. This was proof how fast things change.”
“The ambulance arrived faster then I could have ever imagined and took her sugars, which were 1.2 (and should be above four),” Abma added. “They administered sucrose and in minutes she started crying clearly scared.
“No it is not my fault this happened to her but it is hard not to blame yourself, this is a lesson learned and hopefully other parents can take something from this and make sure you are checking the rooms in your house because they can be as dangerous as a hot car.
“Still I’m in shock and I can’t imagine what would have happened if I didn’t go check on her.”
Parents were thankful for the warning.
“How terrifying oh my goodness,” one person wrote. “I’m so glad she’s ok. I would not have known this either. Thanks for sharing Jenn to help another family from having this happen.”
Another wrote: “I’m so sorry this happened. I had heatstroke as a child, and it’s the worst feeling. Thank you for spreading the word about the dangers.”