Color of blood during the menstrual cycle: brown, black or red - does it matter?
Menstrual blood colour ranges from bright red to dark brown and black — and this is usually perfectly normal. Shade changes depend on flow rate, blood age and hormonal status. Learn when colour variation is physiological and when it requires a gynaecological check-up.
What Does Menstrual Blood Colour Tell You About Your Health?
Menstrual blood can vary in colour from light pink to dark brown, and each shade can provide insight into your reproductive health. Understanding these changes helps you recognise what is normal and when you should consult a gynaecologist.
Light Pink Blood
Light pink colour usually indicates:
- Beginning or end of the menstrual cycle — a normal occurrence
- Low oestrogen levels — may be a sign of hormonal imbalance
- Implantation bleeding — light bleeding 6–12 days after conception
- Anovulatory cycle — a cycle without ovulation
Bright Red Blood
Bright red colour is most common in the middle of the menstrual period:
- Normal occurrence: Indicates fresh, active menstruation
- Most common on days 2–3 of the cycle when bleeding is heaviest
- If accompanied by clots larger than 2.5 cm or lasting longer than 7 days — consult a gynaecologist
Dark Red or Maroon Blood
Dark red blood is common and usually harmless:
- Occurs in the morning or at the start of the period — blood that has remained in the uterus longer
- Normal occurrence in women with heavier cycles
- May occur when using hormonal contraception
Brown or Dark Brown Blood
Brown discharge at the beginning or end of menstruation is almost always normal:
- Old blood: Blood that has oxidised before leaving the uterus
- Typical in the final days of menstruation
- May appear as "spotting" between cycles — usually harmless, but worth checking if persistent
Grey or Greyish Colour
This is the only colour that requires urgent gynaecological attention:
- May indicate bacterial vaginosis — an infection requiring treatment
- Accompanied by unpleasant odour, itching or burning
- May be a sign of miscarriage in early pregnancy
- Definitely book an appointment if you notice a grey tinge
When to Visit a Gynaecologist?
Variations in menstrual blood colour are generally normal. However, contact your gynaecologist if you notice:
- Recurring bleeding between periods
- A period lasting longer than 7 days
- Exceptionally heavy bleeding (changing a pad every hour)
- Grey colour or unpleasant odour of discharge
- Pain that does not respond to standard painkillers
Written by
Dr Slobodanka Petković
Specialist in Gynaecology & Obstetrics · 35+ years of experience
Patients often ask
Brown colour indicates older blood that remained in the uterus longer before being expelled. This is usually perfectly normal and typically occurs at the very start or end of a period, when flow is slower. Haemoglobin oxidation turns bright red into brown shades.
Black blood is usually just older blood retained even longer in the uterus — it is physiologically harmless. It may appear at the very start of a period or after a pause in flow. Concern only arises if black blood has an unpleasant odour, is accompanied by pain or fever.
Bright red indicates fresh blood and active flow — most common in the middle of a period when bleeding is heaviest. This is a completely normal finding indicating the usual rate of endometrial shedding.
Pink blood occurs when menstrual blood mixes with cervical mucus, diluting it. It is common at the very start or end of a period. It may also appear in women with low oestrogen levels or in early pregnancy (implantation bleeding). If pink bleeding occurs outside your cycle, consult a gynaecologist.
Small clots (up to 2.5 cm) are a normal part of heavier menstrual bleeding — they form when anticoagulant enzymes cannot process blood quickly enough. If clots are larger than a coin or occur with heavy bleeding every cycle, gynaecological assessment is recommended to rule out polyps, fibroids or coagulation disorders.
Book an appointment if: menstrual blood has an unpleasant (purulent) odour, grey or greenish blood appears (possible infection), inter-cycle bleeding is frequent, your period lasts longer than 7 days, or you notice large clots with severe pain. Also if there is a sudden change in your established pattern.