Kim Kardashian usually looks picture-perfect, but recent photos show that the curvy reality-TV personality is balding, and her weight loss and pregnancy hormones may be to blame. While out shopping with fiancé Kanye West last week, the 33-year-old new mother wore her hair up in a bun, and around her hairline, patches were clearly visible.

(View photo here.)

“It is well known that … when you have a baby, most women find they seem to be losing a lot more hair than normal,” celebrity hair expert Tatiana Karelina tells RadarOnline. “What with the rapid amount of weight Kim lost dieting in the months after [her child's] birth, this may have even accelerated the hair loss, creating sparser-looking patches that we can clearly see along the hairline.”

Kardashian lost more than 50 pounds following the birth of daughter North in June, and credited her weight loss to the Atkins diet, a low-carbohydrate meal plan. With carbs drastically reduced, the dieter consumes more protein and fat than he/she would on a standard diet. The body then uses fat as fuel, causing rapid weight loss.

Kim is not the only Kardashian sister facing hair loss. Younger sister Khloe also appears to be losing hair, and Beverly Hills dermatologist Dr. Douglas Hamilton (who has never treated the star) says it could be from hormone changes or stress. Khloe filed for divorce in December, after months of speculation that her NBA-star husband Lamar Odom cheated on her with numerous women and indulged in substance abuse. The pair married four years ago after a 30-day courtship. In November, Odom admitted to cheating on Kardashian, 29, in a bizarre rap video while drunk. In August, he was arrested on charges of driving under the influence. “This, in and of itself, is heart-breaking and torture to my soul,” she tweeted after filing.