The glossary

When tissue like the womb lining grows into the muscle wall of the womb, often causing heavy, painful periods.

In: Adenomyosis: endo’s lesser-known cousin, Heavy periods: what counts and what helps, Period cramps but no period: common causes

Attention deficit hyperactivity disorder: a condition that affects focus, energy and impulse control. It starts in childhood and is recognised less often in girls and women.

In: ADHD and your cycle

The medical word for absent periods, either never starting or stopping for several months.

In: Missing periods (amenorrhoea)

Not having enough healthy red blood cells to carry oxygen, often caused by low iron. Can leave you tired and breathless.

In: Fibroids: common, non-cancerous, worth knowing, Your thyroid and your cycle, Anaemia: when heavy periods drain your battery and 4 more

Hormones like testosterone that everyone makes. Higher levels can cause acne, extra hair growth or scalp hair thinning.

In: Acne and skin through your cycle, Hair and your hormones, PCOS (now PMOS): the friendly guide

A cycle in which no egg is released. It is common in the first years of periods and in perimenopause.

In: Irregular cycles: what is going on?, Signs you’re ovulating, Period lasting longer than 7 days: what to know

Warning signs before a migraine, such as zigzag lines, flashing lights or pins and needles.

In: The mini pill (progestogen-only pill), Contraception in your 40s and 50s, Menstrual migraines

Feeling teary, anxious or irritable in the first days after birth. Very common and usually passes within 2 weeks.

In: Postpartum mood: blues, depression and getting help

A common imbalance of vaginal bacteria, often causing thin, fishy-smelling discharge. Not classed as an STI, though sex can trigger it.

In: Discharge, decoded, Smell changes down there, Thrush vs BV: the itchy, fishy truth and 1 more

Your lowest resting temperature, taken first thing in the morning. It rises slightly after ovulation.

In: Basal body temperature, explained, Fertility awareness methods: the honest guide, Signs you’re ovulating and 2 more

Focusing on what your body does and how it feels rather than how it looks, without needing to love every part of it.

In: Body image, bloat and being kind to yourself

A yeast (fungus) that normally lives harmlessly on the body and can overgrow to cause thrush.

In: Thrush vs BV: the itchy, fishy truth

Cognitive behavioural therapy: a talking therapy that helps you notice and change unhelpful thought and behaviour patterns.

In: PMS: the week-before, decoded, PMDD: when PMS turns the volume to max, When sadness is more than PMS and 5 more

Cognitive behavioural therapy for insomnia: a short talking therapy that changes the habits and worries that keep you awake. It is the first-choice treatment for long-term insomnia.

In: When poor sleep sticks around: CBT-I

Fluid made by the cervix. Near ovulation it turns clear, slippery and stretchy, like raw egg white, helping sperm swim.

In: Cervical mucus and cervix position, Fertility awareness methods: the honest guide, The four phases, in depth and 4 more

The narrow lower end of the uterus, at the top of the vagina.

In: Vulva vs vagina: an anatomy tour, Cervical mucus and cervix position, Cervical screening (the smear test), explained and 5 more

A highly sensitive organ at the top of the vulva, where the inner lips meet – the main source of pleasure for most people with a vulva.

In: Vulva vs vagina: an anatomy tour, Orgasm basics

A hospital check that uses a magnifying lens to look closely at the cervix. It is offered after some screening results.

In: Cervical screening (the smear test), explained, Bleeding after sex: what it can mean

Agreeing by choice, with the freedom and capacity to make that choice. It can be withdrawn at any time.

In: Consent & communication, Fertility options for trans and non-binary people, How to share your cycle with a partner (safely)

What the empty follicle becomes after ovulation; it makes progesterone for roughly two weeks.

In: The four phases, in depth, Meet your hormones

The main stress hormone, made by the adrenal glands. It helps you respond to stress and regulates energy, inflammation and the sleep-wake cycle.

In: Stress, cortisol and your cycle

Days from the first day of one period to the day before the next; 21 to 35 days is the normal range (NHS).

In: Fertility awareness methods: the honest guide, What actually is a menstrual cycle?, What is a normal cycle length? and 2 more

Breast pain linked to the menstrual cycle, often starting up to two weeks before a period.

In: Breast changes and how to self-check

Daily Record of Severity of Problems: a daily symptom chart doctors use to spot PMS and PMDD patterns over two cycles.

The medical name for painful periods.

In: Yoga for cramps

The medical name for pain during or after sex.

In: Pain during sex: when to get help

A pregnancy that starts outside the womb, most often in a fallopian tube. It cannot continue and needs urgent medical care.

In: How long does it take to get pregnant?, When to get fertility help, Ectopic pregnancy: know the warning signs

Ways to prevent pregnancy after unprotected sex: the copper coil or a morning-after pill.

In: Coils: copper IUD vs hormonal IUS, The contraceptive injection, Emergency contraception: your options and 2 more

Data is encrypted on your device and only decrypted on devices you choose, so the service in between cannot read it.

In: Period tracker without an account: how it works, Period apps and privacy: what happens to your data

A long-term condition where tissue like the womb lining grows outside the womb, often causing pain.

In: Endometriosis: your pain is real, Adenomyosis: endo’s lesser-known cousin, How to talk to your doctor (and be heard) and 7 more

The lining of the uterus (womb), which thickens each cycle and sheds as your period.

In: Endometriosis: your pain is real, What actually is a menstrual cycle?

The brain skills for planning, starting tasks, remembering things and switching focus. Often called your brain's "manager".

In: ADHD and your cycle

A protein that stores iron. A blood test for ferritin shows how full your iron "savings account" is.

In: Anaemia: when heavy periods drain your battery, Iron and your period, Iron, periods and feeling wiped out

The roughly six days each cycle when sex can lead to pregnancy: about five days before ovulation plus the day itself.

In: Basal body temperature, explained, Fertility awareness methods: the honest guide, The four phases, in depth and 5 more

The part of plant foods your body cannot fully digest. Keeps your gut moving and can help you feel full.

In: Bloating and your cycle, Cravings, explained, Steady energy: starchy foods and fibre and 4 more

A non-cancerous growth of muscle and fibrous tissue in or around the womb.

In: Fibroids: common, non-cancerous, worth knowing

A B vitamin (B9). A daily 400 microgram supplement before and in early pregnancy lowers the risk of neural tube defects like spina bifida.

In: PCOS treatments: what the 2023 guideline says, Your preconception checklist, Pregnancy trimesters: a gentle overview and 2 more

A tiny fluid-filled sac in the ovary that holds a developing egg.

In: The four phases, in depth

From day 1 of your period until ovulation; the part of the cycle that varies most in length.

In: The four phases, in depth, Why your predictions shift, Exercise by phase: listen first, plan second and 2 more

A pituitary hormone that wakes up follicles in the ovaries at the start of each cycle.

In: The four phases, in depth, Meet your hormones, How stress, travel and illness affect your cycle and 2 more

Menopause symptoms in the vagina, vulva and bladder, such as dryness, discomfort, pain with sex and more urinary infections.

In: Vaginal dryness, pain and bladder symptoms

High blood sugar that starts in pregnancy and usually goes away after the baby is born. It is found with a glucose test and is very manageable with the right care.

In: PCOS treatments: what the 2023 guideline says, Gestational diabetes: the sugar test and what it means, Your NHS pregnancy: appointments, jabs and rights

A 2-hour blood test with a sugary drink in the middle, used to check for gestational diabetes at 24 to 28 weeks (earlier if you have had it before).

In: Gestational diabetes: the sugar test and what it means

Gonadotropin-releasing hormone: the brain's signal (from the hypothalamus) that tells the pituitary to release FSH and LH.

In: PMDD: when PMS turns the volume to max, Endometriosis: your pain is real, Meet your hormones and 1 more

The type of iron in meat and fish. Your body absorbs it more easily than iron from plants.

In: Iron and your period

The pregnancy hormone that home pregnancy tests detect in your pee. It starts to be made about 6 days after the egg is fertilised.

In: Early pregnancy signs & when to test, Early pregnancy symptoms and testing, Implantation bleeding: what it looks like and when

Periods heavy enough to affect your physical, social or emotional quality of life.

Thick, dark hair growing in places like the face, chest or tummy, often linked to androgens.

In: Hair and your hormones

Human papillomavirus: a very common virus. Some types can cause changes in cervix cells, which is what cervical screening looks for.

In: Cervical screening (the smear test), explained, STI testing & safer sex, Cervical screening if you are trans or non-binary

Hormone replacement therapy: medicine that replaces oestrogen (plus a progestogen if you still have a womb) to ease menopause symptoms.

In: Coils: copper IUD vs hormonal IUS, Contraception in your 40s and 50s, How your cycle changes in perimenopause and 8 more

When periods stop because the brain dials down cycle hormones, often due to stress, low energy intake or very heavy training.

In: How stress, travel and illness affect your cycle

Irritable bowel syndrome: a common long-term condition causing bloating, tummy pain, diarrhoea and/or constipation.

In: Bloating and your cycle, Caffeine, alcohol and your cycle, Gut feelings: bloating and period poos and 3 more

Light spotting around the time a period is due, which can happen in early pregnancy.

In: Early pregnancy signs & when to test, Early pregnancy symptoms and testing, Implantation bleeding: what it looks like and when and 1 more

Regularly finding it hard to fall asleep or stay asleep, or waking too early. It is called long-term when it lasts 3 months or more.

In: Sleep across your cycle, When poor sleep sticks around: CBT-I

When the body responds less well to insulin, so it needs to make more of it to keep blood sugar steady.

In: PCOS (now PMOS): the friendly guide

A small hormone-free T-shaped device placed in the womb. Lasts 5 or 10 years.

In: Thrush vs BV: the itchy, fishy truth, Every contraception method, compared, Coils: copper IUD vs hormonal IUS and 3 more

A small T-shaped device in the womb that releases progestogen. Lasts 3 to 8 years.

In: Adenomyosis: endo’s lesser-known cousin, Fibroids: common, non-cancerous, worth knowing, Missing periods (amenorrhoea) and 8 more

The outer (majora) and inner (minora) lips of the vulva. They come in every shape and size.

In: Vulva vs vagina: an anatomy tour

Keyhole surgery where a tiny camera is passed through a small cut in the tummy to look at (and sometimes treat) the pelvic organs.

In: Endometriosis: your pain is real

Long-acting reversible contraception: the implant, copper coil (IUD), hormonal coil (IUS) and injection.

In: Every contraception method, compared

A pituitary hormone whose sudden surge triggers ovulation; what ovulation tests detect.

In: The four phases, in depth, Meet your hormones, How stress, travel and illness affect your cycle

A sudden rise in luteinising hormone that triggers the ovary to release an egg, usually within about 36 hours.

In: How to use ovulation (LH) tests, How accurate are period tracker apps?

Your sex drive – how much you want sex. It naturally rises and falls.

In: The mini pill (progestogen-only pill), Side effects & switching methods, Meet your hormones and 1 more

Bacteria found in some foods that can cause a rare infection called listeriosis, which is risky in pregnancy.

In: Foods to avoid (and enjoy) in pregnancy

An app design where your data lives on your own device first, and any server copy is optional.

In: Period tracker without an account: how it works

The bleeding and discharge after giving birth, as the womb heals. It usually stops after 6 to 8 weeks, though it can last longer.

In: Postpartum recovery: the first weeks, Periods after birth and breastfeeding

Not eating enough to cover everything your body does, including exercise, growing and daily life. The body can respond by turning the cycle down, so periods get lighter, later or stop.

In: Eating enough, and your periods

The stretch from ovulation to your next period, usually around 10 to 16 days.

In: PMS: the week-before, decoded, PMDD: when PMS turns the volume to max, The four phases, in depth and 7 more

A person's very first period.

In: Your first period

When you have not had a period for 12 months in a row. It usually happens between 45 and 55, and the average age is around 51.

In: Breast changes and how to self-check, Hair and your hormones, Libido through your cycle and 18 more

An older medical term for heavy periods; doctors now often say heavy menstrual bleeding.

The time from the first day of one period to the day before the next.

In: Your thyroid and your cycle, What actually is a menstrual cycle?, Your cycle is a vital sign and 2 more

Paying attention to the present moment, your thoughts, feelings and surroundings, without judging them.

In: Stress, cortisol and your cycle, Mindfulness and breathing quickies, Sleep and mood in perimenopause

German for “middle pain” – a one-sided twinge or cramp some people feel around ovulation.

In: Signs you’re ovulating, Ovulation pain (mittelschmerz): normal or not?

Movement that raises your heart rate and makes you breathe faster, but you can still talk. Brisk walking counts.

In: Moving when your body makes it hard, Bone and heart health after 40, Exercising on your period

The standard due-date estimate: first day of your last period plus 280 days (40 weeks), adjusted for cycle length.

Problems with how a baby’s brain and spine develop early in pregnancy, such as spina bifida. Folic acid lowers the risk.

In: Your preconception checklist, Prenatal vitamins: what you actually need

Iron from plant foods like beans, lentils and greens. Vitamin C helps you absorb it.

In: Iron and your period

Non-steroidal anti-inflammatory drug, such as ibuprofen or naproxen; these reduce prostaglandins.

In: Endometriosis: your pain is real, Cramp relief that actually works

A key reproductive hormone (estrogen in the US). Found in combined methods: the combined pill, patch and ring.

In: Cervical mucus and cervix position, Libido through your cycle, PMS: the week-before, decoded and 18 more

Infrequent periods: cycles longer than about 35 to 38 days, or fewer than nine periods a year.

A condition where bones become weaker and break more easily. Risk rises after menopause.

In: Strength training: your bones will thank you, Bone and heart health after 40, Early menopause and premature ovarian insufficiency and 1 more

When an ovary releases an egg, usually once per cycle.

In: Discharge, decoded, Basal body temperature, explained, Cervical mucus and cervix position and 28 more

Polycystic ovary syndrome (the NHS now also uses the newer name PMOS): a common hormone condition that can cause irregular periods, excess hair and acne.

In: PCOS (now PMOS): the friendly guide, PCOS treatments: what the 2023 guideline says, Missing periods (amenorrhoea) and 8 more

A hammock of muscles at the base of your pelvis that supports your bladder, bowel and womb.

In: Pelvic floor basics, Postpartum recovery: the first weeks, Pain during sex: when to get help

How well a method works when used exactly as directed, every single time.

In: Every contraception method, compared, The combined pill, The mini pill (progestogen-only pill) and 2 more

The years before menopause when hormone levels change and you start to get symptoms, while still having periods.

In: Missing periods (amenorrhoea), Contraception in your 40s and 50s, What is a normal cycle length? and 11 more

Not being able to afford or access period products, facilities or education.

In: Period poverty and greener periods

A dummy pill with nothing active in it. Good trials compare a treatment with a placebo, because just expecting to feel better can change how you feel.

In: PMS supplements: what the evidence says

Premenstrual dysphoric disorder: a severe, cyclical form of PMS where mood symptoms seriously disrupt life in the luteal phase and ease within a few days of your period starting.

In: PMDD: when PMS turns the volume to max, How to talk to your doctor (and be heard), Why your mood shifts across the cycle and 4 more

Polyendocrine metabolic ovarian syndrome, the newer NHS name for polycystic ovary syndrome: a hormonal condition linked to irregular ovulation, higher androgens and insulin resistance.

In: Hair and your hormones, PCOS (now PMOS): the friendly guide, PCOS treatments: what the 2023 guideline says and 7 more

Physical and emotional symptoms in the days before a period that ease once it starts.

In: Bloating and your cycle, Acne and skin through your cycle, PMS: the week-before, decoded and 27 more

The time after you have gone 12 months without a period.

In: What is perimenopause?

A rare but serious mental health emergency after birth (around 1 in 1,000 mothers), with symptoms like confusion, hallucinations or a very high mood. It needs same-day help.

In: Postpartum mood: blues, depression and getting help

A pregnancy condition that causes high blood pressure, usually after 20 weeks. It can also start in the days or weeks after birth. Routine checks look for it.

In: Pre-eclampsia: signs, checks and when to call

When the ovaries stop working normally before age 40. Also called premature menopause. It needs medical support.

In: What is perimenopause?, Early menopause and premature ovarian insufficiency

The hormone that rises after ovulation. It slightly raises body temperature in the luteal phase.

In: Basal body temperature, explained, Libido through your cycle, PMS: the week-before, decoded and 11 more

A man-made hormone that works like the body’s progesterone. Used in most hormonal contraception.

In: PMS: the week-before, decoded, PMDD: when PMS turns the volume to max, PCOS (now PMOS): the friendly guide and 18 more

Gradually making strength exercises a bit harder over time, so your muscles keep adapting.

In: Strength training: your bones will thank you

Hormone-like chemicals that make the womb contract during your period. More of them usually means stronger cramps.

In: The four phases, in depth, Gut feelings: bloating and period poos, Cramp relief that actually works and 1 more

Relative Energy Deficiency in Sport: when someone does not eat enough for the energy they use, which can stop periods and affect bones and health.

In: Exercising on your period

Going over the same worries or thoughts again and again without reaching a solution.

In: Anxiety in the luteal phase

A lab test that checks the amount, movement and shape of sperm in a semen sample.

In: Sperm health: male fertility basics, When to get fertility help

Combined HRT for people who still have periods: oestrogen every day plus a progestogen for part of the month, usually leading to a monthly bleed.

In: HRT options compared: patches, gels, tablets and more

A brain chemical messenger involved in mood, sleep and appetite. Shifts in sex hormones may affect how it works.

In: PMS: the week-before, decoded, Why your mood shifts across the cycle

Light bleeding outside a period: a few drops or brown streaks, not enough to need a pad.

In: Cervical screening (the smear test), explained, The mini pill (progestogen-only pill), The contraceptive implant and 18 more

Sexually transmitted infection, like chlamydia, gonorrhoea, herpes or HIV. Many have no symptoms.

In: Discharge, decoded, Smell changes down there, Thrush vs BV: the itchy, fishy truth and 11 more

A study that searches for every good trial on one question and weighs them together, instead of picking favourites. It is only as strong as the trials inside it.

In: Cycle syncing: an evidence check, How stress, travel and illness affect your cycle, ADHD and your cycle and 1 more

Taking the combined pill with shorter, fewer or no breaks – a safe option to discuss with a pharmacist or doctor.

In: The combined pill, Side effects & switching methods, Delaying your period

A common yeast infection that can cause itching and thick, white, cottage-cheese-like discharge.

In: Discharge, decoded, Smell changes down there, Thrush vs BV: the itchy, fishy truth and 3 more

A rare but serious reaction to bacterial toxins, linked in some cases to tampon or cup use.

In: Period products, compared

A non-hormonal medicine that helps blood clot, used to make heavy periods lighter.

In: Adenomyosis: endo’s lesser-known cousin, Fibroids: common, non-cancerous, worth knowing, How your cycle changes in perimenopause and 1 more

Taken through the skin, as a patch, gel or spray. For HRT, transdermal oestrogen does not raise blood clot risk the way tablets slightly do.

In: HRT: a balanced look, HRT options compared: patches, gels, tablets and more

One of the three stages of pregnancy: weeks 1 to 12, 13 to 27, and 28 to birth.

In: Pregnancy trimesters: a gentle overview, Pregnancy loss: you are not alone, Pre-eclampsia: signs, checks and when to call

Thyroid-stimulating hormone: the main blood test used to check how your thyroid is working.

In: Your thyroid and your cycle

A gap between the two long tummy muscles that is common after pregnancy and usually closes by about 8 weeks after birth.

In: Postpartum recovery: the first weeks

How well a method works in real life, including forgotten pills and late refills.

In: Every contraception method, compared, The combined pill, The mini pill (progestogen-only pill) and 1 more

Urinary tract infection – an infection in the bladder (cystitis), urethra or kidneys.

In: UTIs: burning questions answered, Vaginal dryness, pain and bladder symptoms, Lube 101 and 2 more

The internal muscular canal from the vulva to the cervix.

In: Discharge, decoded, Vulva vs vagina: an anatomy tour, Smell changes down there and 10 more

The community of mostly friendly bacteria (largely lactobacilli) that keeps the vagina healthy and slightly acidic.

In: Thrush vs BV: the itchy, fishy truth

When the vaginal muscles tighten automatically on penetration, making it painful or impossible. Very treatable.

In: Pain during sex: when to get help

The medical name for hot flushes and night sweats.

In: Hot flushes: what helps

Hard-working exercise where you cannot say more than a few words without pausing for breath, like running.

The outside genital area: labia, clitoris, and the openings of the urethra and vagina.

In: Vulva vs vagina: an anatomy tour, Thrush vs BV: the itchy, fishy truth, UTIs: burning questions answered and 4 more

Long-lasting pain in the vulva without an obvious cause.

In: Pain during sex: when to get help

Grains that keep their outer layers, like brown rice, oats and wholemeal bread. More fibre and nutrients than white versions.

In: Magnesium: the hype and the help, Steady energy: starchy foods and fibre, Iron, periods and feeling wiped out

The bleed you can get in the pill-free break or on dummy pills. It is a response to the hormone pause, not a true period.

In: The combined pill, What is a normal cycle length?, Delaying your period