It has yet to be confirmed what exactly landed Kardashian in the hospital on Wednesday night, but Jenner and her boyfriend Corey Gamble were photographed entering the West Hills, CA, hospital around 9:45PM, with Chyna arriving separately, Us Weeklyreported.
According to a source, Kardashian, 29, suffered a diabetic attack.
"He's been so stressed out so [he's] not taking care of himself or eating right. Stress affects his diabetes," the source told Us of the Rob & Chyna star, who has reportedly been living separately from Chyna since their blowout fight and unofficial split last week.
Kardashian -- who also admitted he tends to get stressed during the holidays -- and Chyna, 28, reportedly reconciled and are currently in counseling to address the new father's insecurities and jealousy issues.
Kardashian learned of his type 2 diabetes diagnosis in Summer 2015, and after refusing to take insulin, he was hospitalized in December of that year. He recently toldPeople he felt like he "was going to die" at the time.
Kardashian, who once weighed about 300 pounds, has struggled with dramatic weight gain for years as well as depression.
"When I got out of the hospital, I knew I needed to make changes," Kardashian said of last year's "big-time" health scare. "Chyna and I had a really big talk and she told me that by having her cook for me, my diabetes would be gone."
Kardashian revealed to People in August 2016 he was diabetes-free, but his nutrition and exercise routine haven't been consistent in recent months, seemingly due to his roller-coaster romance with Chyna.
Rob & Chyna has been renewed for a second season to air in 2017 on E!.