For most women, menstruation consists of 2–3 days of heavy blood flow followed by another 2–4 days of lighter flow. The menstrual flow from the vagina is a mixture of blood and tissue from the inner lining of the uterus. Women vary considerably in the volume of blood that is lost each month; it can be as little as 4 tablespoons or as much as 12 tablespoons. On average, a woman loses about 30–50 ml of blood per period — though losing up to 80 ml is still considered normal.
There are a variety of factors that affect the color of menstrual blood, including hormonal activity, the age of the blood, and infection. It pays to be aware of the different ways that period blood can present and what this may indicate about your health.
At the start of your period, you can expect the blood to be bright red. During this phase of the cycle, the lining of your uterus is being shed at a rapid pace and you’ll likely experience some menstrual cramps. These pains in the abdomen are the result of an increase in the production of prostaglandins, which cause the smooth muscle in the uterus to contract.
Menstrual cramping, or period pain, is a common symptom for many women and is usually nothing to worry about. It can easily be treated with a hot water bottle over your abdomen or over-the-counter painkillers. If you opt for painkillers, choose a non-steroidal anti-inflammatory drug (NSAID) like ibuprofen from your local drug store or supermarket.
In some cases, intensive flow of bright red blood can be an indication of miscarriage, ectopic pregnancy, submucosal fibroid, endometrial or cervical polyp, endometrial or cervical cancer, or an ovarian cyst. If you have any concerns about menstrual symptoms or your general health, seek advice from a trusted healthcare professional — they are in the best position to assess your circumstances and offer the most suitable range of treatment options.