If you've experienced spotting and nausea after a workout that targeted your abdominal muscles, there's likely no cause for concern. Spotting during exercise -- especially intense exercise -- occurs frequently in women, especially right before their periods. In addition, doing a series of difficult stomach crunches can trigger feelings of nausea.
Many women experience spotting just before their periods begin. In some women, hard workouts can trigger abnormal bleeding, according to FitSugar. Some women also experience spotting at the midpoints in their menstrual cycle, when they're ovulating. If your spotting and nausea occurs at one of these two times, it's probalby normal.
Believe it or not, it's also not unusual to experience nausea as you work your ab muscles. According to the Military.com, you probably can blame motion sickness for your nausea. As you perform ab exercises, such as stomach crunches, you actually can jostle your head enough that you start to feel dizzy and nauseated -- classic signs of motion sickness.
To avoid spotting and nausea after an ab workout, cut back on the intensity of your workout, especially during the times in the month when you are more likely to experience these conditions. Also, keep your focus on one specific spot in the sky or on the ceiling as you're performing stomach crunches. This will minimize jostling that may bring on nausea.
It's possible that spotting and nausea after your ab workouts could be a sign of pregnancy. If this is a possibility, take a pregnancy test to rule out that reason for your symptoms. In addition, if your spotting and nausea worsen or continue for more than a few days, consult your physician for a complete checkup.