Six months after the birth of her second child, E! reality star Kourtney Kardashian is back in a bikini -- and proudly showing off her 44-pound weight loss in a series of unretouched pictures for Us Weekly!

Posing poolside in Miami Dec. 13, the Kourtney and Kim & Take Miami star shared her diet and fitness secrets in a full-length interview with West Coast Bureau Chief Rebecca Bienstock.

"It was harder to lose weight the second time around," admitted Kardashian, mom to son Mason, 3, and daughter Penelope, 6 months (with partner Scott Disick**, 29). "I gained 45 pounds with Penelope."

Now a lean 106 pounds, the 5-foot star credits pro Tracy Anderson's 90-minute dance-focused workouts and small portion sizes for helping her slim down in record time. "This time, the focus is really on being a mom and being present, knowing my priorities," Kardashian, 33, told Us.

For details on how Kardashian got her post-baby body back -- and her thoughts on marriage and having a third child -- pick up the new issue of Us Weekly, on stands Friday!

This article originally appeared on Usmagazine.com: Kourtney Kardashian Loses 44 Pounds in 6 Months: How She Got Thin!