Stretch marks are very common during and after pregnancy, in part because the hormones associated with the pregnancy make the skin friable and prone to developing them. After the pregnancy is over, the stretch marks do tend to improve over time. Initially, they tend to be bright red or pink in people with lighter skin, and very dark in people with darker skin, fading to lighter colors over months. They do not, unfortunately, tend to go away completely.
If you are interested in dealing with your stretch marks, you can talk to either your primary care doctor
or a dermatologist
If the stretch marks are not very noticeable, they may simple suggest that you wait awhile, as they do tend to fade over time. There are also a few prescription creams that have been shown to have some effects on reducing the prominence of stretch marks and helping them 'fade' into the surrounding skin color, and your doctor can discuss these options with you. These creams work best on red stretch marks and less well on stretch marks that have already faded to white. A final option for some people with mature stretch marks is a laser-based therapy, which is something that a dermatologist could discuss with you.