The New York Times film Framing Britney Spears explores the career of the singer, the treatment of her by paparazzi and the conservatorship she's been held under since 2008.
Kardashian shared to her Instagram Stories on Friday that she had watched it and felt "a lot of empathy" for Spears because of the media coverage of her when pregnant with her eldest child North West.
"The way the media played a big role in [Spears'] life the way it did can be very traumatising and it can really break even the strongest person," the 40-year-old wrote.
The mother-of-four continued: "Looking back at my own experiences, I remember a time when I felt this way. When I was pregnant with North I was suffering from preeclampsia, which made me swell uncontrollably.
"I gained 60lbs and delivered almost 6 weeks early and I cried every single day over what was happening to my body mainly from the pressures of being constantly compared to what society considered a healthy pregnant person should look like - as well as being compared to Shamu the whale by the media.
"Looking at all of the photos of myself online and in magazines made me so insecure and I had this fear of wondering if I would ever get my pre baby body back. I was shamed on a weekly basis with cover stories that made my insecurities so painful I couldn't leave the house for months after. It really broke me."
The reality star went on to say she took her "frustrating, embarrassing" feelings to motivate her forwards, but that it did take a mental toll.
"You just never fully know what someone is going through behind the scenes and I've learned through my own experiences that it's always better to lead with kindness," she said.
Kardashian then posted covers from US magazines that had commented on her weight and appearance, with some comparing her figure with Kate Middleton who was pregnant at the same time.
Watch: Kelly Rowland doesn't want to watch Britney Spears documentary