Clear and white discharge
Clear, stretchy mucus is your fertile fluid at work, appearing in the days before ovulation under rising oestrogen. The milky white kind is the luteal-phase version: progesterone thickens the mucus into a lotion-like consistency for the second half of every cycle.
Both are completely normal at every point in the cycle. The only white worth acting on is the cottage-cheese kind: a thick, lumpy texture with itching or soreness is the classic yeast infection pattern, and that is a treat-and-move-on situation rather than a worry.
If you want to place where you are in your cycle from your mucus alone, our cervical mucus calculator identifies your stage from a few simple observations.
Yellow discharge
Yellow is a spectrum, and context decides everything.
Pale yellow, no smell, no irritation is usually innocent: white mucus oxidises to yellow on fabric and pant liners, and what looked alarming in your underwear is often just chemistry with air. Hormonal fluctuations can also tint cervical fluid faintly cream to yellow around ovulation and premenstrually.
Bright, deep or mustard yellow, especially with a strong or unpleasant smell, frothy texture, or pelvic discomfort, points towards infection, most classically trichomoniasis. That is treatable with a short course of antibiotics, but it does need a proper test first: guessing between infections based on colour alone is unreliable even for clinicians.
Light green discharge
Green is the colour to take seriously. A light green tint is classically associated with trichomoniasis, and it also appears with some bacterial infections. It is rarely explainable by hormones alone.
A faint greenish tinge that lasts hours and coincides with, say, a new detergent or the tail end of a period can be a one-off. But a persistent green colour, at any volume, with or without smell or itching, deserves a proper swab test. The good news: the causes are among the most treatable in all of women’s health, usually with a single course of medication. The uncomfortable part is only the waiting.
During pregnancy, the bar is even lower: any green tinge is a mention-it-at-your-next-appointment minimum, and if it appears alongside smell, itching or discomfort, call sooner. Infections in pregnancy are treated more promptly precisely because leaving them is riskier.
Pink discharge
Pink is white mucus with a trace of blood, and its meaning is almost entirely about timing. Mid-cycle pink suggests ovulation spotting; pink 6 to 12 days after ovulation can be implantation bleeding; pink in the day or two before your period is usually premenstrual spotting as the flow gears up; pink on hormonal birth control is often simple breakthrough bleeding.
We have a full guide to light pink spotting when you wipe, including the nine most common causes. The short version: pink on its own is rarely a problem, but recurring pink between periods over several cycles is worth a routine check.
Brown discharge
Brown is old blood that took its time leaving the uterus, oxidising on the way. The usual appearances: the tail end of a period, spotting at ovulation, implantation bleeding around 6 to 12 DPO, or premenstrual spotting before the real flow starts. Brown at the very start or end of a period is so normal it barely registers.
It earns a doctor’s visit when it recurs between periods across multiple cycles, appears after menopause, or comes with pelvic pain. The kind that shows up once and vanishes is usually just your uterus being thorough about housekeeping.
Grey or frothy discharge
Grey is the one colour on this list with essentially no benign explanation. Grey, especially with a fishy smell that intensifies after sex, is the textbook picture of bacterial vaginosis, the most common vaginal infection in reproductive-age women. Frothy, yellow-green fluid points towards trichomoniasis.
Both are straightforward to diagnose with a swab and simple to treat. Neither is a hygiene failure or a moral verdict; bacterial vaginosis in particular is a microbiome balance issue that happens to healthy vaginas. But grey and frothy are the textures and colours that warrant an actual appointment rather than watchful waiting.
Mucus mixed with period blood
Stringy, mucus-streaked period blood alarms a lot of people and is almost always normal. Cervical mucus and menstrual flow share the same exit route, so on lighter days the mucus that would usually pass unnoticed comes out mixed with blood instead. Jelly-like strands, clear streaks through red flow, and small soft clots on heavy days are all standard period anatomy.
What is worth a conversation with your GP: repeatedly passing clots larger than a 10p coin, a sudden change to much heavier flow, or bleeding that lasts beyond seven days. Those are heaviness markers, not colour emergencies.
Discharge colors during pregnancy
Pregnancy shifts the baseline: rising oestrogen and blood flow to the cervix produce leukorrhoea, a thin, milky-white, mild-smelling fluid that increases steadily across the trimesters. White and clear remain the normal colours throughout.
The colours that matter in pregnancy: pink or brown can be implantation, cervical sensitivity, or something needing assessment, so mention it; green or grey need prompt attention even without smell; anything with a strong smell, froth or itching gets the standard workup. And bright red bleeding at any point in pregnancy is always worth a call, however light, if only for reassurance.
When to see a doctor
Bring any of these to a GP, gynaecologist or sexual health clinic:
- A grey colour, or a green tint lasting more than a day or two
- Frothy texture, or a strong or fishy smell
- Cottage-cheese texture with itching or soreness
- Changes in what you are seeing alongside pelvic pain, fever or pain during sex
- Pink or brown spotting recurring between periods across multiple cycles
- Any new colour pattern during pregnancy, and any bleeding in pregnancy
Most colour changes turn out to be hormonal weather, not disease. But the ones that are infections are genuinely miserable untreated, and remarkably quick to fix diagnosed, so the check is always worth it.
A note from Kanika: I used to photograph my toilet paper like a crime scene investigator. What actually helped was learning the two colours that mean “book an appointment” (grey and green) and treating everything else as information about where I am in my cycle. What you are seeing is not trying to scare you; nine times out of ten it is just your hormones leaving a note.