Why is my period blood brown

Noticing brown menstrual blood can cause confusion or concern, especially if you expect the bright red flow you see in adverts. In most cases brown blood during your period is perfectly normal and simply reflects older blood leaving the uterus. By understanding what brown blood means, why it appears and when it may signal a problem, you can approach your cycle with confidence and know when to seek medical advice.

What causes blood to look brown
Blood turns brown as it ages. Fresh menstrual flow appears bright or dark red because the blood has just left the uterine lining. If blood remains in the uterus or vagina for longer before passing, exposure to oxygen causes it to oxidise and turn brown. This process is similar to how an apple slice left out in the air turns brown. Brown period blood most often appears at the very beginning or end of menstruation when flow is lighter and movement is slower.

Brown blood at the start of your period
Many women see small amounts of brown spotting a day or two before their period officially begins. This early shedding of the uterine lining is common and simply represents old blood releasing at the tail end of the previous cycle. If you have a long menstrual cycle or irregular periods, the spotting may last several days before the heavier red flow starts. This pre period spotting usually requires no treatment and resolves as soon as the main flow begins.

Brown blood at the end of your period
As your period ends, the uterine lining has largely shed. Remaining blood may take longer to exit the body, allowing it to oxidise and appear brown. This final shedding phase can last a day or two and often involves light spotting rather than a steady flow. Wearing a light pad or panty liner during this time helps you stay comfortable. Once all the older blood has cleared, your cycle resets until the next period.

Light flow and brown blood throughout
Some women experience consistently light periods with brown blood throughout rather than distinct bright red days. This pattern may indicate a low oestrogen level, which can occur in teenage years, during perimenopause or as a side effect of certain contraceptive pills. It may also follow significant weight loss, intense exercise or stress. If light brown flow is your usual pattern and you feel well otherwise, it is unlikely to be harmful. However, if your flow has become suddenly lighter or you have other symptoms such as fatigue or hair loss, discussing this with your GP can help rule out hormonal imbalances.

Implantation bleeding and early pregnancy spotting
Light brown spotting that occurs around the time your period would be due may sometimes represent implantation bleeding. When a fertilised egg attaches to the uterine lining, small blood vessels can break, causing spotting. Implantation bleeding typically lasts one or two days, is lighter than a normal period and is often lighter in colour, ranging from pinkish brown to dark brown. If you suspect implantation and have missed your period, a home pregnancy test a few days after the spotting can provide clarity.

Contraception and brown bleeding
Hormonal birth control methods such as the combined pill, hormonal coil or contraceptive implant commonly cause breakthrough bleeding and brown spotting, especially in the first few months of use. This occurs because the altered hormone levels affect the stability of the uterine lining, causing it to shed irregularly. In most cases the spotting settles after three to six cycles. If brown bleeding persists or is heavy enough to require pads between periods, your GP or clinic can review your method and adjust the dosage or suggest an alternative.

Perimenopause and changing cycles
As women approach menopause, typically in their mid to late forties or early fifties, hormone levels begin to fluctuate. These changes often lead to irregular cycles with altered flow and spotting. Brown bleeding between periods is a common feature of perimenopause as oestrogen and progesterone levels rise and fall unpredictably. If you are over forty and notice longer gaps between periods, lighter or darker blood, or spotting between cycles, these are likely signs of perimenopause. Tracking your cycle and discussing symptoms with your GP can help you manage any discomfort.

Potential causes of concern
While brown blood is usually benign, there are scenarios when it merits medical attention. Persistent brown bleeding between regular periods lasting more than a few months, heavy flow requiring more than one pad or tampon every hour for several hours, pelvic pain, unusual vaginal discharge or spotting after sex should prompt a GP consultation. These symptoms can sometimes indicate infections such as pelvic inflammatory disease, cervical polyps or more rarely endometrial abnormalities that require investigation.

Infections and inflammation
Infections of the uterus, cervix or vagina can cause irregular bleeding and brown discharge. Common culprits include bacterial vaginosis, thrush and sexually transmitted infections such as chlamydia. Inflammation from irritation or allergic reactions to soaps, douches or spermicides may also result in brown spotting. If you experience itching, burning, unusual odour or discomfort along with brown blood, a swab test at the sexual health clinic or GP surgery can identify the cause and guide treatment.

Polyps and fibroids
Benign growths in the uterus or cervix, such as polyps or fibroids, can cause irregular bleeding and brownish spotting between periods or after sex. Polyps are small leathery lumps attached to the uterine lining or cervical canal. Fibroids are benign muscle tumours of the uterine wall. Both conditions can be detected by ultrasound and often treated with medication, removal of the growth or in some cases surgical procedures to preserve fertility.

Endometrial conditions
Endometriosis and adenomyosis can lead to brown blood and spotting. In endometriosis tissue similar to the uterine lining grows outside the womb, causing painful periods and irregular bleeding. Adenomyosis involves endometrial tissue growing into the uterine wall leading to heavy or prolonged bleeding and brown discharge. Both conditions often cause pelvic pain and bloating. Referral to a gynaecologist for imaging or laparoscopy may be necessary for diagnosis and management.

Managing brown period blood at home
For mild brown spotting at the start or end of your period, simple measures often suffice. Wearing a panty liner rather than a pad can feel more comfortable during light flow days. Maintaining good hygiene with fragrance free cleansing products helps prevent irritation. Avoiding sexual intercourse when spotting and using condoms when you resume an active cycle reduces the risk of infections. Gentle exercise and stress reduction techniques such as yoga or meditation support hormonal balance and may improve flow regularity.

When to seek professional advice
Consult your GP if you experience brown bleeding alongside significant pain, changes in mood or sleep, unusual vaginal discharge, fever, rapid heart rate or dizziness. If you are over forty and have irregular cycles, or under forty with new heavy or painful periods, a medical review helps rule out conditions that require treatment. Your GP may perform a pelvic examination, request an ultrasound or refer you to a specialist for hysteroscopy or biopsy if needed.

Summary
Brown period blood most often indicates older blood leaving the uterus and is commonly seen at the beginning or end of menstruation. Dietary factors, hormonal contraception, life stages such as perimenopause, implantation in early pregnancy and mild infections can all lead to brown spotting. While usually harmless, persistent, heavy or painful brown bleeding warrants medical evaluation. With proper care and timely professional advice you can manage brown period blood confidently and maintain your reproductive health.