Taking birth control could help with bone-density building and prevention of osteoporosis. "Some studies have shown that combined oral contraceptive pills may increase bone density due to the protective effect of estrogen, but there are considerable concerns about starting combined oral contraceptive pills in the teen years before peak bone mass is reached," says Jennifer Landa, MD, a gynecologist and chief medical officer at BodyLogicMD in Maitland, Florida. If you're concerned about bone loss, talk to your doctor to see if the pill might be helpful for you.