If you're experiencing breakthrough bleeding during or after exercise, you probably don't need to worry about it. Spotting occurs fairly commonly in women, usually right before their menstrual periods, and a few women do have breakthrough menstrual bleeding that's due to intense exercise, according to the Centre for Menstrual Cycle and Ovulation Research. But if your breakthrough bleeding worsens or you experience pain, talk to your doctor about it, since it might signal a medical problem.
During your period, your uterus sheds its lining--causing menstrual bleeding--because you did not get pregnant, according to McKinley Health Center at the University of Illinois at Urbana-Champlain. Although the majority of women experience heavier bleeding at the start of their periods, about 10 percent seem to begin their periods with spotting and breakthrough bleeding.
Breakthrough bleeding during or after exercise occurs most frequently when you're following a very intense workout, especially if you're a teenager and you haven't had your period for very long, according to the Centre for Menstrual Cycle and Ovulation Research. Young women who lose weight as a result of an intense workout routine sometimes experience breakthrough bleeding due to exercise.
In most cases, breakthrough bleeding during or after exercise doesn't represent a true medical concern, according to the fitness magazine FitSugar. However, you may want to make your workouts less strenuous. Cutting back on the length or the intensity of your workouts might stop the breakthrough bleeding.
If your breakthrough bleeding continues or worsens, or if you stop getting your period altogether, schedule a complete checkup with your obstetrician-gynecologist. Some women with abnormal bleeding, including breakthrough bleeding, suffer from disorders such as polycystic ovary sydrome or diabetes, according to Northshore University HealthSystem. To make sure exercise really is causing your breakthrough bleeding, you'll need to rule out other potential conditions.