A pregnant mum credits her Apple Watch with saving her life after its heart rate warning led to doctors finding blood clots in her lungs.
Rebecca McManus, 24, had been feeling breathless for weeks but chalked her symptoms up to asthma and being 22 weeks pregnant.
The mum from Clydebank, Scotland, then received a red alert warning from her smartwatch on April 30, after her resting heart rate jumped to 154bpm.
The NHS says a normal resting heart rate should be anywhere between 60 and 100bpm.
Rebecca was taken to hospital where doctors identified two pulmonary embolisms - clots in blood vessels in the lungs that can be life-threatening if not treated quickly, the DailyRecord report.
Brit 'saw her insides' after being cut open by propeller on luxury diving tripThe expectant mum is now on blood thinners and credits her Apple Watch with saving her life.
She said: "I was feeling tired and out of breath but I expected that with my second pregnancy.
"I'd walked up two flights of stairs to my flat and I was struggling to breathe.
"I sat down on the couch and my watch alerted me that my heart rate was at 140bpm for over 10 minutes, as if I had been exercising.
"I didn't believe it until I stood up and felt dizzy. Then it went up to 154bpm.
"If it wasn't for my Apple Watch, I wouldn't have realised the danger I was in. It saved my life."
Rebecca went to A&E at the Queen Elizabeth University Hospital in Glasgow, where she had her blood taken and was given a chest X-ray and an electrocardiogram (ECG).
However, doctors put the symptoms down to her baby pushing up into her diaphragm and sent her home.
When her dizzy spells and high heart rate failed to subside, Rebecca went to her GP three days later.
After watching her heart rate skyrocket from 80bpm to 140bpm just by standing up from a chair, she was immediately referred back to hospital.
Cowboy gored to death by bull in New Year's Eve rodeo tragedyFurther tests showed the mum had two life-threatening clots in her lungs.
Pregnant women experience a heightened risk of blood clots and leaving them untreated can lead to strokes, heart attacks and death.
Rebecca is furious that her symptoms were dismissed three days before the clots were found and now plans to submit a complaint to NHS Greater Glasgow and Clyde.
She continued: "It is ridiculous that I was sent home after being told I was 'just pregnant'.
"I could have died in a few months thinking my symptoms were just my pregnancy.
"One blood clot can be fatal and I was walking around with two."
An NHS Greater Glasgow and Clyde spokesperson said: "While we cannot discuss the details of any case due to the need for patient confidentiality, we would like to apologise to Ms McManus for the distress she has experienced. If she does submit a formal complaint, it will be fully investigated by the relevant teams.
"However, if in the meantime she would like to discuss any aspect of her care, we would encourage her to contact us.