A faint pink mark on toilet paper, brown discharge mid-cycle, or bleeding that arrives after sex can make the rest of the day feel uncertain. If you are asking what causes spotting between periods, the short answer is that there are several possible reasons, from hormonal shifts to contraception, infection or changes to the cervix. The more useful answer is that unexpected bleeding deserves attention without panic.
You are not dramatic for noticing it, and you are not wasting anyone's time by raising it with a clinician. Most causes are not serious, but bleeding between periods is worth discussing, particularly when it is new, persistent, recurrent or paired with other symptoms.
What counts as spotting?
Spotting usually means a small amount of vaginal bleeding outside the expected days of your period. It may be pink, red, rust-coloured or brown; brown blood often means blood has taken longer to leave the uterus or vagina, rather than signalling a particular cause by itself. There is no perfect boundary between spotting and a light period, and the pattern over time, with any accompanying symptoms, usually says more than the colour alone.
What causes spotting between periods?
Hormonal variation is a common explanation. Some people have light bleeding around ovulation, which often occurs roughly halfway through a cycle. Stress, significant weight change, intensive exercise, illness and the years leading up to menopause can all affect ovulation and the hormones that shape the uterine lining, making bleeding less predictable.
Hormonal contraception can cause breakthrough bleeding, especially in the first months after starting or changing a pill, implant, injection, hormonal coil or patch, or after missed doses. This does not always mean the method is unsuitable, but check the relevant instructions and speak with the clinician or service that prescribed it if bleeding is troublesome or continues.
Pregnancy should be considered if there is any chance of it, including when contraception has been used. Light bleeding can occur in early pregnancy for a range of reasons, and it should not automatically be labelled implantation bleeding, a term that offers more certainty than the evidence allows in an individual case. Because bleeding in pregnancy can sometimes signal miscarriage or ectopic pregnancy, seek clinical advice promptly.
Changes to the cervix or vagina can cause bleeding after sex or between periods. Cervical ectropion, where delicate cells sit on the outer surface of the cervix, is common and usually harmless. Cervical polyps, vaginal dryness and friction can contribute. So can sexually transmitted infections, which matter enough here to take separately.
Other possibilities include fibroids, uterine polyps, endometriosis, adenomyosis and conditions affecting how blood clots, and some medicines, including anticoagulants, make bleeding more likely. Less commonly, unexplained bleeding can be associated with changes in the cervix, uterus or vagina that need investigation, including cancer. That is not the most likely explanation, but it is one reason not to put persistent bleeding aside.
Bleeding after menopause should always be assessed. The NHS advises contacting a GP about vaginal bleeding after menopause, even if it happens only once and even if it is light.
When spotting is the only sign of an infection
Some sexually transmitted infections announce themselves quietly, or not at all. Chlamydia is the clearest example: most people who have it notice no symptoms, and when a sign does appear, bleeding between periods or after sex is sometimes the only one. Infections can inflame the cervix, leaving it more delicate and more likely to bleed with contact; gonorrhoea can behave similarly, and unusual discharge, pelvic pain or pain during sex may or may not come with it.
This matters beyond the bleeding itself. Untreated chlamydia can spread to the uterus and fallopian tubes as pelvic inflammatory disease, which can affect fertility. Treatment, once the infection is found, is usually a straightforward course of antibiotics, which is the practical case for testing early rather than watching and waiting.
Asking for an STI test is not an admission, and being offered one is not an accusation. It is how one possible cause gets ruled in or out, in exactly the way a pregnancy test rules another in or out. The test itself is usually simple: often a self-taken vaginal swab or a urine sample, through a GP or sexual health clinic, without an examination. Testing is particularly worth it if you have a new partner, have not been screened since your current relationship began, or notice bleeding after sex; the NHS advises anyone under 25 who is sexually active to test for chlamydia yearly and with each new partner. If an infection is found, current and recent partners need testing and treating too, otherwise it simply returns.
When to seek urgent help
Seek immediate medical care if you might be pregnant and have bleeding with one-sided lower abdominal pain, severe abdominal pain, shoulder-tip pain, dizziness, fainting or feeling very unwell. These can be signs of an ectopic pregnancy and need urgent assessment.
Heavy bleeding also needs prompt care, particularly if you are soaking through pads or tampons quickly, passing large clots, feeling faint, short of breath or having chest pain. Trust the change in your own body. You do not need to calculate the exact volume of blood before asking for help.
Make a non-urgent appointment with a GP, sexual health clinic or gynaecology service if spotting lasts more than a few cycles, keeps returning, happens after sex, occurs after menopause, or comes with pelvic pain, fever, unusual or foul-smelling discharge, itching, pain when passing urine or pain during sex. If you are overdue for cervical screening, arrange that too, but screening is not a test for every cause of bleeding and should not replace an assessment of new symptoms.
A record matters most when spotting keeps coming back
Unexpected bleeding is easy to minimise once it stops, then hard to describe weeks later. A dated record is not surveillance of yourself. It is a practical way to communicate what happened without being expected to remember every detail under pressure.
Here is why the record earns most when spotting recurs. A single episode is an anecdote, and anecdotes are easy to dismiss, usually by you, before a clinician ever hears about it. Dated episodes across cycles are a pattern, and pattern is what a clinician actually works with. Where the bleeding falls matters: mid-cycle spotting, bleeding after sex, and spotting in the days before a period point toward different explanations, so the dates do not just decorate the story, they help shape the Differential Assessment. So do the companions: cycle day, pain, discharge, recent sex, missed contraception, a new medicine. Spotting recorded alongside your other cycle symptoms tells a clinician far more than spotting recorded alone.
The simple floor: note the first and last day of bleeding, whether it was spotting or more like a period, and where it fell in your cycle. If it feels manageable, add colour, whether it followed sex, contraception changes, pregnancy possibility, pain, discharge and relevant test results. A few honest entries beat a flawless reconstruction. And some attention rarely pays you back: repeatedly searching each change in colour, testing for pregnancy earlier than a test can reliably answer, or comparing your cycle with strangers' accounts online. Record what you notice, then let a clinician interpret the pattern in context.
Feminal lets you record cycle information, symptoms, medications and supplements in one place, dated as you go, and if your clinician uses Feminal too, that pattern is visible to them between appointments: not one remembered episode, but the recurrence across months, alongside everything else your cycle was doing. It supports the conversation. It does not diagnose the cause of bleeding.
What a clinician may ask about
Expect questions about your usual periods, contraception, sexual health, pregnancy possibility, medicines and whether bleeding follows sex. Depending on your symptoms and history, a clinician may suggest a pregnancy test, STI testing, examination, blood tests, ultrasound or referral. Not everyone needs every test; the next step depends on your age, bleeding pattern, history and accompanying symptoms. NICE guidance on heavy menstrual bleeding and NHS guidance on bleeding between periods both support looking at the full pattern rather than treating all unexpected bleeding as the same problem, which is exactly why the dates, context and associated symptoms matter.
Sources used
NHS guidance on vaginal bleeding between periods or after sex, chlamydia, bleeding in pregnancy, ectopic pregnancy and postmenopausal bleeding. NICE guidance on heavy menstrual bleeding. RCOG patient information on early pregnancy bleeding and ectopic pregnancy.
Your body does not need to meet a threshold of drama before it is worth mentioning. If spotting is new, keeps returning, or does not feel like your normal pattern, write down the dates, bring them to your clinician, and let the question be taken seriously.