When women become pregnant, most of them change their body shape. For the lucky few, they are able to retain their pre-pregnancy body. Sadly, it's hard to do that, and even if you're still stickly thin after giving birth, you can't avoid a few flabs here and there. Most mothers, especially first timers, get depressed when they look in the mirror and see themselves in a strange new body. 

Seeing a different "you" should not deter you from being fit. Take for example, Karen Lee, a mother of a 17-month-old baby boy who attends the workout classes. "I enjoy the community," she said. She goes to these classes, not just to stay fit, but to make connections with other moms. 

Courtney Furr also attends this type of classes with her two kids in tow - 3-month-old Alice and 2-year-old Juliet. For her, it's wonderful being able to go out without having to worry about leaving her kids or looking up child care services. 

According to Oregon Live, both women take classes with Fit4Mom, a national franchise offering a week of free classes in the Portland area from November 16 to 21, aiming to introduce moms to its programs. 

Shauna Treseder, personal trainer at NW Women's Fitness Club in Northeast Portland, specializes in "motherhood fitness" and has four children. She has important tips for mothers who are looking forward to effectively managing their weight loss program. 

First, every postpartum recovery is unique. It is not ideal to compare it to others women as pregnancies, delivery and babies are all different.

Next, the postpartum phase is forever. Getting pregnant and giving birth can cause physical problems. Not to mention the fact that being a parent means getting a lot of stress and fatigue. Most common postpartum problems are back pain, diastasis rectus abdominis, which involves separation of the abdominal muscles; and pelvic floor disorders and can affect women who enjoy high-impact exercise including running or jumping. She recommends physical therapy to deal with such problems.

Another one would be accepting the new body. "It's best to just love and accept this new, often beautiful body and make it the healthiest and strongest that you can, instead of thinking constantly of what it once was," Treseder said. "You will be so much happier letting go of that."