She urged migraine sufferers to speak with their doctor prior to starting the pill.
Hailey Bieber has claimed being on the contraceptive pill was a contributing factor to the mini-stroke she suffered in March.
In a video posted to her YouTube channel on Wednesday, the model spoke about the health scare that hospitalised her and opened up about why doctors think she "had the blood clot in the first place".
"One was that I had just recently started birth control pills, which I should have never been on because I am somebody who suffers from migraines anyway," she shared. "And I just did not talk to my doctors about this.
"So ladies, if you suffer from bad migraines and you plan on being on birth control pills, make sure you tell your doctor because having a stroke is a potential side effect from birth control pills," she warned.
The 25-year-old was hospitalised on March 10 and later shared in a statement that she had suffered stroke-like symptoms caused by a blood clot on her brain.
In the YouTube video, Hailey described feeling a "weird sensation" in her right arm while having breakfast with her husband, Justin Bieber. When he asked if she was okay, she "couldn't speak".
"The right side of my face started drooping, I couldn't get a sentence out," she told viewers. "Immediately, I thought I was having a stroke."
She went on to say a medic examined her as an ambulance was called, with the facial drooping lasting around 30 seconds and her struggle to verbalise a response to questions continuing for a longer period.
"By the time I got to the emergency room, I was pretty much back to normal – could talk, wasn't having any issues with my face or my arm," she explained, adding that she stayed in the hospital overnight and underwent a series of tests.
Though she scored a 0 on the stroke checklist in the emergency room, her scans showed the clot had deprived her brain of oxygen for a period of time and that she had suffered a Transient Ischemic Attack, more commonly referred to as a mini-stroke.
Hailey said doctors pinpointed three factors that likely contributed to the stroke: her battle with Covid, her back-and-forth travelling to Paris "in a really short amount of time", and the contraceptive pill, which she had recently started taking without informing her doctor of her frequent migraines.
According to research by Loyola Medicine stroke specialists, oral contraceptives can "increase the risk of ischemic stroke" (strokes caused by blood clots) in women – but the risk is "very small" among those who don't have other stroke risk factors.
The specialists say such contraceptives have no impact on the risk of hemorrhagic strokes, which are caused by bleeding in the brain.
