The reality TV personality and her partner Scott Disick welcomed daughter Penelope Scotland in July 2012.
Kardashian showed off her slimmed down figure in a bikini photoshoot for the new issue of Us Weekly, also sharing her diet and fitness secrets.
The Kourtney and Kim & Take Miami star – who is also mother to three-year-old son Mason, admitted: "It was harder to lose weight the second time around. I gained 45lb with Penelope."
Kardashian said that she now weighs 106lb, and credited her weight loss to small portion sizes and Tracy Anderson's 90-minute dance-focused workouts.
The 33-year-old added: "This time, the focus is really on being a mum and being present, knowing my priorities."
Kardashian's sister Kim recently confirmed that she is expecting her first child with boyfriend Kanye West.