The 36-year-old rapper has reportedly forbidden his girlfriend - who gave birth to the couple's first child, daughter North, in June - from going under the knife to enhance her looks after his mother Donda West died following complications from a similar procedure.
A source told RadarOnline.com: "Kim was certain that she wanted to have surgery after giving birth because she wanted a head start on losing her baby weight.
"Kanye told Kim in no uncertain terms that she needed to put her baby and her life first. He got pretty emotional because he really didn't want her going through that kind of major surgery. He's still traumatised from his mum's death."
Donda died in 2007 at the age of just 58 after suffering "multiple post-operative factors" following liposuction and breast-reduction surgery.
The source explained: "Kanye was devastated by her passing and it's made him extremely protective of those he loves.
He really put his foot down and told Kim the surgery ban is a condition of being with him."
Meanwhile, 32-year-old Kim - who has admitted to having Botox in the past - has been following a gruelling exercise regime and has been following the Atkins Diet in a bid to regain her pre-baby figure.