Kim Kardashian is once again taking on rumors that she has undergone surgery to insert butt implants. She took to Twitter to slam the reports, which have surfaced once again.

She called the rumors “nonsense” and explained tabloids were using pictures of her from before she gave birth to her daughter, North West.

The Keeping Up with the Kardashians star tweeted in part, “Get a life! Using pics of me 15lbs skinnier (before I had my baby) comparing to me now! I still have weight to lose.”

She continued, “Anyone who has had a baby knows how hard it is to lose weight(especially the last bit of weight) & your body totally changes! Making fun of me pregnant & making fun of me trying to lose weight now shame on you. I'm not perfect but I will never conform to your skinny standards sorry! Not me. And BTW I've lost a lot so far & I'm proud of that! Don't give young girls a complex!”

ABC News reports Kardashian gave birth to her first child with fiancé Kanye West on June 15, a couple of weeks earlier than planned. Throughout her pregnancy she was scrutinized for the weight she gained.

Since giving birth, she’s been on the Atkins diet and on a strict workout regimen. Although she’s lost about 40 pounds since then, she continues to get flack in the press.

Back in October, she posted a revealing picture of herself in a swimsuit, which she later told Jay Leno was a "middle finger to the world" for calling her fat.

image: NBC