Pregnant reality TV star Kim Kardashian is undergoing tests for diabetes.

The Keeping Up With The Kardashians star is expecting her second child with her rapper husband Kanye West, and she has suffered a frightening health scare.

In scenes for an upcoming episode of the show, Kim is seen telling her family members that doctors have been doing extra tests because she is at risk of developing pre-eclampsia, a condition which can occur in the later stages of pregnancy.

"The doctors saw more fluid than usual in my placenta, which can mean I have diabetes," she declares before adding, "Once you have pre-eclampsia you are at risk of having it again."

Kim was previously diagnosed with pre-eclampsia while expecting her daughter, North West, and she recently opened up about her struggles with pregnancy in a post on her website.

"For me, pregnancy is the worst experience of my life!" she wrote. "I don't enjoy one moment of it and I don't understand people who enjoy it... Maybe it's the swelling, the backaches or... how your body expands and nothing fits. I just always feel like I'm not in my own skin...

"People just don't tell you all of the gross things that happen during pregnancy or after. Do you know you basically have to wear a diaper for two months afterwards!... No one told me that! #SoSexy (sic)."

Kim is expecting a son to join her daughter, and the baby is due at the end of the year (15).

She recently revealed the couple is still mulling over names for their little boy: "I do like the name Easton," she explained to TV host Ellen DeGeneres. "I don't think my husband likes that name, but I do like it. I don't think we'll go another direction (sic). It's definitely not South... Everytime someone says South I wanna roll my eyes... I do like Easton, I don't think Kanye likes Easton. I'm not sure."