Short version: your period blood changes colour through your cycle, and most of the time that is completely normal. Colour mostly comes down to one thing; how old the blood is by the time it leaves. Fresh and fast looks bright red. Slow and older looks brown or almost black. A couple of shades are worth flagging to a GP, and we will get to those. No panic required, just a bit of body literacy.
Why does period blood change colour?
It is mostly about time and air. Blood that leaves quickly stays bright red. Blood that hangs around a little longer before it exits oxidises and turns brown or darker. That is why you often see darker blood first thing in the morning or at the very start and end of your period, when the flow is slower. Your flow, your hormones and where you are in your period all play a part, so some variation month to month is normal, not a red flag.
What does brown period blood mean?
Usually, old blood taking its time. Brown or dark brown often shows up at the beginning or tail end of your period, or as spotting between periods. On its own it is rarely something to worry about. If brown spotting keeps happening mid-cycle, or turns up alongside pain or an unusual smell, it is worth a mention to your GP.
What does bright red period blood mean?
Fresh, steady flow. Bright red is blood leaving quickly, which is why it is most common in the first couple of days when things are moving. It is the shade most people picture when they think period, and it is a good sign your flow is doing its thing.
What do dark red or almost black period blood mean?
Also, usually just older blood, especially on heavier days or when you have been lying down and it pools before leaving. Very dark or black clots can look alarming but are often normal on a heavy day. That said, if you are regularly passing large clots, soaking through a pad or period underwear every couple of hours, or your period is genuinely heavy, that is worth getting checked. Heavy bleeding is common and it is also very treatable. More on heavy flow.
What does pink period blood mean?
Often blood mixed with cervical fluid, which can happen with lighter flow, spotting, or around ovulation. It can also show up if your flow is on the lighter side generally. Usually nothing to worry about. If it comes with persistent spotting between periods, flag it.
What about orange or grey period blood?
These two are the ones to pay attention to. Orange blood, or discharge with an off smell, can sometimes point to an infection. Grey discharge can be a sign of an infection too, and if there is any chance you could be pregnant, grey needs prompt medical attention. You do not need to diagnose yourself from a colour, but if you see orange or grey with itching, an unusual smell or discomfort, book in with a healthcare professional to be safe.
So when should you actually see a doctor?
Colour alone rarely tells the whole story but book a check-in if you notice any of these: bleeding between periods that keeps happening, an unusual or strong smell, orange or grey blood or discharge, periods that are getting heavier or longer over time, or severe pain that stops your day. Severe period pain is not something to brush off. More on extreme period pain. You know your normal. If something has clearly changed, that is reason enough to ask.
Quick answers
Q: Is it normal for period blood to change colour?
A: Yes. Most colour changes just reflect how old the blood is. Bright red is fresh, brown or black is older blood leaving slowly. Some variation across your period is completely normal.
Q: What does brown period blood mean?
A: Usually old blood, common at the start or end of your period or as light spotting. On its own it is rarely a concern. If it is happening mid-cycle or with pain, mention it to your GP.
Q: Is dark or black period blood bad?
A: Not usually. It is often just older blood on a heavier or slower day. Large frequent clots or very heavy bleeding are worth getting checked.
Q: When should period blood colour worry me?
A: Orange or grey blood or discharge, an unusual smell, bleeding between periods, or periods getting heavier over time are all worth a GP visit. Speak to a healthcare professional if you are unsure.
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