Menstrual blood may appear orange if it mixes with mucus or other vaginal fluids, explains HealthTap. In the absence of other abnormal symptoms, an orange hue is not typically cause for concern.
In women with otherwise normal periods that last three to seven days, blood color and the presence or absence of clumps are not usually significant symptoms, according to U by Kotex. Menstrual blood may have a dark brown or black color when a woman is nearing the end of her period, as the blood being expelled at this time is older than the blood released earlier on in the period, notes WebMD.
Women sometimes notice blood clots in their menstrual blood, often on days when the bleeding is especially heavy. Although a woman's body releases anticoagulants while she is menstruating to prevent the blood exiting her body from clotting, these anticoagulants are sometimes unable to work in time when the flow is particularly rapid and heavy, explains WebMD. As a result, some clots escape with the expelled blood. The presence of these clots is normal unless they are larger than the size of a quarter or being released in excessive quantities, in which case the woman should speak with a health care provider to check that an underlying condition is not to blame for the large amounts of clotting.