For example, it’s not safe to have sex when your blood counts are too low because your body might not be protected from normal bacterial when your immune system is weak. Also, the thin lining of the vagina and anus can be easily torn – so a low platelet count (platelets help your blood to clot) increases the risk of serious bleeding. There can still be some risks, even while your blood counts are at an acceptable level. So, in order to protect your health, carefully consider the decisions you make about having sex and talk to your doctor for more information about your situation.