Here’s an excert from her interview with Vogue below:
The next day, while recovering in the hospital, Serena suddenly felt short of breath. Because of her history of blood clots, and because she was off her daily anticoagulant regimen due to the recent surgery, she immediately assumed she was having another pulmonary embolism. (Serena lives in fear of blood clots.) She walked out of the hospital room so her mother wouldn’t worry and told the nearest nurse, between gasps, that she needed a CT scan with contrast and IV heparin (a blood thinner) right away. The nurse thought her pain medicine might be making her confused. But Serena insisted, and soon enough a doctor was performing an ultrasound of her legs. “I was like, a Doppler? I told you, I need a CT scan and a heparin drip,” she remembers telling the team. The ultrasound revealed nothing, so they sent her for the CT, and sure enough, several small blood clots had settled in her lungs. Minutes later she was on the drip. “I was like, listen to Dr. Williams!”
Williams also had issues after her C-section birth including her wound becoming open after coughing spells and a large hematoma found in her abodomen.