Olympic medallist and former 100-metre world champion showed signs of undergoing labour when discovered dead on May 2.
Bowie, who won three medals at the 2016 Rio de Janeiro Games, was found dead last month. She was 32.
The report from the office of the medical examiner in Orlando, Florida, said Bowie was estimated to be eight months pregnant and showing signs of undergoing labour when she was discovered dead on May 2.
It said she was found in bed in a “secured residence” with possible complications including respiratory distress and eclampsia. The autopsy report said “the manner of death is natural”.
Bowie’s agent Kimberly Holland told CBS News the news on Monday would end the “hurtful” speculation about the cause of death.
“Unfortunately, so many people, including the media, are making speculations that she did something to herself, which is very hurtful,” she said.
“So hopefully, now knowing the truth, there will be many apologies.”
Black women have the highest maternal mortality rate in the United States – 69.9 per 100,000 live births for 2021, almost three times the rate for white women, according to the Centers for Disease Control and Prevention.
According to the Orange County Sheriff’s Office, deputies responded in early May to a home in the area “for a wellbeing check of a woman in her 30s who had not been seen or heard from in several days.” She was later identified as Frentorish “Tori” Bowie.
The toxicology results were negative and the autopsy report listed bipolar disorder in her medical history.
Bowie grew up in Mississippi after being taken in by her grandmother as an infant. As a teenager, she considered herself a basketball player and only reluctantly showed up for track, where she blossomed into an elite sprinter and long jumper. She attended the University of Southern Mississippi, where she swept the long jump NCAA championships at the indoor and outdoor events in 2011.
At the 2016 Rio Olympics, Bowie won silver in the 100 and bronze in the 200. She then ran the anchor leg on a 4×100 team with Tianna Bartoletta, Allyson Felix and English Gardner to take gold.
A year later, she won the 100 metres at the 2017 world championships in London. She also helped the 4×100 team to gold.
“A talented athlete, her impact on the sport is immeasurable, and she will be greatly missed,” United States Track and Field chief executive Max Siegel said in a statement in May.
US sprinting great Justin Gatlin paid tribute to Bowie last month as a “fierce competitor and great teammate”.
“Tori was a beautiful human being and had a smile that made you want to smile, too,” Gatlin said. “A true legend that made her mark in our sport and hearts.”