Menstrual Disorders — Types, Causes, Diagnosis & Treatment Guide — Symptoms, Causes & Treatment | MyMedicPlus

Menstrual disorders encompass a broad range of conditions affecting the menstrual cycle — including the timing, frequency, duration, quantity, and symptom profile of menstruation. Normal menstruation occurs every 24-38 days (cycle length), lasts 4-8 days, involves blood loss of 5-80mL per cycle (above 80mL is defined as heavy menstrual bleeding/HMB), and should not be severely painful or functionally debilitating. Menstrual disorders significantly impair quality of life, physical health, work and school attendance, and reproductive outcomes for millions of women. The FIGO (International Federation of Gynaecology and Obstetrics) PALM-COEIN classification (2011, updated 2018) provides a structured framework for abnormal uterine bleeding (AUB): Structural causes (PALM): Polyp, Adenomyosis, Leiomyoma (fibroids), and Malignancy/hyperplasia. Non-structural causes (COEIN): Coagulopathy, Ovulatory dysfunction, Endometrial, Iatrogenic, and Not yet classified. Major categories of menstrual disorders: Heavy menstrual bleeding (HMB — formerly menorrhagia): blood loss above 80mL per cycle causing quality of life impairment; Dysmenorrhoea: painful menstruation — primary (no underlying pathology — prostaglandin-mediated) or secondary (due to endometriosis, adenomyosis, fibroids); Oligomenorrhoea (cycles more than 35 days apart); Amenorrhoea (absence of menstruation — primary or secondary); Premenstrual syndrome (PMS) and PMDD; Polycystic ovary syndrome (PCOS) — anovulatory cycles; and Intermenstrual or postcoital bleeding.

Causes vary by type of menstrual disorder. Heavy menstrual bleeding (HMB) — PALM-COEIN causes: Structural — uterine fibroids (leiomyomata — most common cause of HMB in premenopausal women; submucous fibroids particularly disruptive to endometrium); adenomyosis (endometrial glands and stroma within the uterine myometrium — causes HMB, dysmenorrhoea, and uterine enlargement); endometrial polyps (focal benign overgrowths of endometrium); endometrial carcinoma or hyperplasia (must be excluded — particularly in perimenopausal women and those with risk factors). Non-structural — coagulopathy (von Willebrand disease in up to 20% of women with HMB — the most common inherited bleeding disorder in women presenting with HMB); ovulatory dysfunction (PCOS, thyroid disease, hyperprolactinaemia); endometrial causes (localised endometrial NSAID/prostaglandin dysregulation without structural lesion); iatrogenic (anticoagulants, copper IUD, breakthrough bleeding on hormonal contraception). Dysmenorrhoea — Primary: excessive endometrial prostaglandin F2alpha and E2 production causes intense, prolonged uterine muscle contractions and ischaemia — begins within 1-2 years of menarche, typically without structural pathology. Secondary: endometriosis (the most common cause of secondary dysmenorrhoea — cyclical pain due to endometrial implants outside the uterus — on ovaries, peritoneum, rectovaginal septum — responding to the menstrual cycle); adenomyosis; fibroids; pelvic inflammatory disease (PID); and IUD (particularly copper — in first months of use). Amenorrhoea/oligomenorrhoea: primary amenorrhoea (absence of menstruation by age 16 — Turner syndrome 45XO, Müllerian agenesis, hypothalamic dysfunction, premature ovarian insufficiency); secondary amenorrhoea (cessation of periods for more than 3 months in a previously menstruating woman — most commonly pregnancy (must always be excluded first); PCOS (the most common cause — anovulation from LH/FSH imbalance and androgen excess); functional hypothalamic amenorrhoea (FHA — from excessive exercise, low BMI/eating disorders, or extreme stress — causing reduced GnRH pulsatility); hyperprolactinaemia; thyroid disease; Asherman's syndrome; premature ovarian insufficiency (POI) — ovarian failure below age 40 — affects 1% of women). PCOS causes: insulin resistance, excess LH stimulation of ovarian androgen production, impaired follicular maturation, chronic anovulation. Premenstrual disorders: cyclical symptoms from days 1-14 of the luteal phase (after ovulation), resolving with menstruation — driven by central nervous system sensitivity to normal fluctuations in progesterone/oestrogen and their metabolites; severe form (PMDD) involves debilitating mood symptoms.

Heavy menstrual bleeding (HMB): flooding (menstrual blood soaking through a pad or tampon hourly for several consecutive hours); passage of large clots; need for double protection (pad + tampon); menstrual bleeding lasting more than 7-8 days; anaemia from chronic blood loss (pallor, fatigue, breathlessness, reduced exercise tolerance); social and occupational disruption (avoiding activities, missing work, reduced quality of life). Dysmenorrhoea: lower abdominal cramping pain beginning 1-2 days before or at menstrual onset; pain radiating to the back or thighs; nausea and vomiting; diarrhoea; headache; fainting; severity ranges from mild to debilitating (missed school/work). Secondary dysmenorrhoea: pain worsening over time (endometriosis typically worsens progressively with each cycle), starting before menstruation (endometriosis — mid-cycle or constant pain also possible), deep dyspareunia (painful sex — characteristic of endometriosis particularly involving the posterior cul-de-sac, uterosacral ligaments, or rectovaginal septum). PCOS: irregular, infrequent, or absent periods; symptoms of androgen excess — hirsutism (facial and body hair in a male pattern), acne, scalp hair thinning (androgenetic alopecia); weight gain; infertility from anovulation; polycystic ovaries on ultrasound (12+ follicles per ovary, or ovarian volume above 10mL). Amenorrhoea: absence of periods — in secondary amenorrhoea from FHA, there may be symptoms of oestrogen deficiency (reduced libido, vaginal dryness, hot flushes); in POI, menopausal symptoms; in Asherman's syndrome, minimal or absent symptoms. Premenstrual syndrome (PMS)/PMDD: cyclical symptoms in the luteal phase — mood changes (irritability, depression, anxiety, emotional lability), bloating, breast tenderness, headache, poor sleep, reduced concentration — PMDD is the severe form causing significant functional impairment.

History: detailed menstrual history (cycle length, duration, blood loss estimation — PBAC/pictorial blood loss assessment chart; passage of clots; onset age, change in pattern); symptoms of anaemia, androgen excess, pain characteristics (timing relative to cycle — primary vs secondary dysmenorrhoea); contraceptive and medication history; fertility intentions; family history (coagulopathy, endometriosis). Examination: BMI and weight (obesity and low BMI both affect menstrual cycles); acanthosis nigricans (insulin resistance — PCOS); hirsutism scoring (Ferriman-Gallwey); pelvic examination (uterine size — enlarged in fibroids/adenomyosis; adnexal tenderness or mass; fixed retroversion — endometriosis). Blood tests: FBC (anaemia — iron deficiency from chronic blood loss); serum ferritin; thyroid function (TSH); prolactin; LH and FSH ratio (LH:FSH above 2:1 in PCOS); testosterone (total and free), DHEAS, SHBG (androgen excess in PCOS); oestradiol and FSH on day 2-5 (ovarian reserve, POI assessment); coagulation screen and von Willebrand factor/VWF antigen and activity (for suspected coagulopathy in women with HMB since menarche). Pelvic ultrasound: first-line structural assessment — identifies fibroids (size, number, location — submucous/intramural/subserosal), adenomyosis features (heterogeneous myometrium, globular uterine enlargement), ovarian pathology (PCOS morphology — polycystic ovaries), ovarian cysts (endometrioma — 'chocolate cyst' — on TVS: a homogeneous echogenic ovarian cyst), endometrial thickness and texture (polyps — saline infusion sonohysterography/SIS improves polyp detection). Endometrial biopsy (Pipelle aspirate): indicated for unexplained HMB in women over 45, persistent intermenstrual bleeding, or risk factors for endometrial cancer (obesity, PCOS with prolonged amenorrhoea, tamoxifen use, hereditary non-polyposis colorectal cancer/Lynch syndrome). Hysteroscopy and laparoscopy: hysteroscopy (direct visualisation of the uterine cavity and endometrium — gold standard for polyp and submucous fibroid diagnosis and treatment); laparoscopy (gold standard for endometriosis diagnosis — visual inspection and biopsy). Pregnancy test: mandatory before investigating any menstrual disorder in a woman of reproductive age.

Heavy menstrual bleeding (HMB) — treatment by type: Levonorgestrel-releasing intrauterine system (LNG-IUS — Mirena, Kyleena): the most effective non-surgical treatment for HMB — reduces menstrual blood loss by 75-95%; also reduces dysmenorrhoea; lasts 5 years; NICE first-line recommendation for HMB without intracavitary pathology. Tranexamic acid (1g three times daily during menstruation): antifibrinolytic — reduces HMB by 40-50%; non-hormonal — suitable for women wishing to conceive; improves quality of life. NSAIDs (mefenamic acid 500mg TDS, naproxen, ibuprofen during menstruation): reduce HMB by 20-30% and treat dysmenorrhoea; non-hormonal. Combined oral contraceptive pill (OCP): regulates cycle and reduces HMB by 40-50%; also treats dysmenorrhoea. Progestogen-only treatments: oral norethisterone 5mg TDS days 5-26 of cycle (effective short-term management while awaiting investigations or definitive treatment); depot medroxyprogesterone acetate; progestogen-only pill (limited evidence for HMB but useful in women contraindicated to oestrogen). GnRH analogues (goserelin, nafarelin — achieve medical menopause): used pre-operatively to shrink fibroids and correct anaemia; short-term use (maximum 6 months) due to hypoestrogenic side effects; add-back HRT reduces bone loss. Uterine artery embolisation (UAE): radiological intervention — emboli injected into uterine arteries reduce blood flow to fibroids; 80-90% achieve significant reduction in HMB; preserves uterus; fibroid symptoms recur in 20-30% at 5 years. Endometrial ablation: surgical destruction of the endometrium by various energy sources (thermal balloon, microwave, rollerball, bipolar radiofrequency — 2nd generation techniques under general anaesthesia or sedation); reduces HMB by 80-90%, amenorrhoea in 30-50%; suitable for completed family planning; not suitable if intracavitary pathology present. Myomectomy: surgical removal of fibroids with preservation of uterus; either hysteroscopic (submucous fibroids) or laparoscopic/open (intramural, subserosal); 80% report significant improvement in HMB; 10-year fibroid recurrence rate 25-30%. Hysterectomy: definitive cure for HMB — 100% satisfaction for HMB; laparoscopic total hysterectomy preferred; vaginal or abdominal alternatives. Dysmenorrhoea: NSAIDs (naproxen, mefenamic acid, ibuprofen — started 1-2 days before expected period, continued through worst days — reduces pain by 60-70%); combined OCP (suppresses ovulation and reduces prostaglandin production — highly effective for primary dysmenorrhoea and reduces endometriosis-related pain); continuous OCP cycling (skipping pill-free intervals) for maximum pain control; LNG-IUS. Endometriosis treatment: surgical excision of endometriotic lesions (laparoscopic excision or ablation — gold standard for definitive diagnosis and treatment; reduces pain and improves fertility); hormonal suppression (combined OCP, progestogens, GnRH analogues, dienogest — reduces endometriosis-related pain but not definitively curative; lesions recur when treatment is stopped). PCOS: weight loss (5-10% weight reduction restores ovulation in 55-80% of overweight women with PCOS; the single most effective treatment for PCOS in overweight women); metformin (improves insulin resistance, reduces androgens, induces ovulation; reduces risk of gestational diabetes in PCOS pregnancy); combined OCP (regulates cycle, reduces androgens — treats hirsutism and acne; suitable for those not seeking pregnancy); clomiphene citrate or letrozole (ovulation induction for fertility). POI: HRT until age 51 (reduces cardiovascular, bone, and cognitive consequences of premature oestrogen deficiency); refer to fertility specialist for egg donation options. FHA: weight restoration, reduce exercise intensity, psychological support (CBT for eating disorders or excessive exercise); bone protection with HRT.

Iron-deficiency anaemia (the most common complication of heavy menstrual bleeding — affecting 30-60% of women with HMB; causes fatigue, reduced exercise tolerance, cognitive impairment, and reduced quality of life; requires iron supplementation and treatment of the underlying cause). Infertility and subfertility (from anovulation in PCOS, endometriosis, and Asherman syndrome; from tubal damage in pelvic inflammatory disease; treatment depends on underlying cause). Endometrial hyperplasia and endometrial carcinoma (from chronic anovulation with unopposed oestrogen — PCOS, obesity, perimenopause; 3-fold higher endometrial cancer risk in untreated PCOS; progestogen or combined OCP protects the endometrium). Bone density loss (from oestrogen deficiency in functional hypothalamic amenorrhoea and premature ovarian insufficiency — DEXA scan indicated; HRT or oestrogen-containing contraception required). Psychological impact: depression, anxiety, school and work absence, and relationship difficulties from severe or untreated menstrual disorders.

Many menstrual disorders are not fully preventable, but early recognition and management can significantly reduce their impact. Regular gynaecological health checks from adolescence: menstrual problems should not be normalised as 'just part of being a woman' — severe dysmenorrhoea, HMB, or irregular cycles warrant assessment, as these may indicate treatable underlying conditions (endometriosis is often diagnosed 7-12 years after symptom onset due to normalisation of pain). Maintaining a healthy weight: obesity worsens HMB (increases oestrogen from adipose aromatase, stimulating endometrial proliferation), PCOS, and endometrial cancer risk; conversely, underweight/extreme exercise causes FHA and bone density loss from oestrogen deficiency — both are preventable with appropriate weight management. Period tracking: apps or diaries enable women to recognise abnormal patterns (irregular cycles, heavy bleeding, worsening pain) and seek care earlier. Prompt treatment of urogenital infections: PID causing secondary dysmenorrhoea is preventable with STI screening and prompt antibiotic treatment of Chlamydia and Gonorrhoea. Contraception counselling: LNG-IUS (Mirena) not only provides highly effective contraception but prevents HMB and may reduce endometriosis pain — an important consideration for women with menstrual disorders not planning immediate pregnancy. For PCOS: early diagnosis and lifestyle intervention reduces long-term risks of metabolic syndrome, type 2 diabetes, and endometrial cancer (from unopposed oestrogen in chronic anovulation — progestogen or OCP recommended to protect the endometrium in women with oligomenorrhoea/amenorrhoea from PCOS).

Seek emergency care immediately for: very heavy vaginal bleeding soaking more than 1 pad per hour for 2+ consecutive hours (risk of haemorrhage and severe anaemia requiring urgent assessment); heavy bleeding combined with severe abdominal pain and a positive pregnancy test (possible ectopic pregnancy or miscarriage — emergency assessment required); and symptoms of severe anaemia with heavy bleeding — breathlessness at rest, palpitations, near-syncope (requires urgent treatment). See your GP within 1-2 weeks for: periods that have become significantly heavier, more painful, or more irregular than before; periods stopping unexpectedly when not pregnant (secondary amenorrhoea — needs assessment); any postcoital (after sex) bleeding or intermenstrual (between periods) bleeding — needs urgent gynaecological assessment to exclude cervical or endometrial pathology; and dysmenorrhoea that is not adequately controlled by OTC NSAIDs and is affecting quality of life. Seek gynaecological assessment for: suspected endometriosis (worsening dysmenorrhoea, deep dyspareunia, pelvic pain, subfertility — endometriosis diagnosis and treatment requires specialist laparoscopy); suspected fibroids (HMB with pelvic heaviness or pressure, urinary frequency); and irregular cycles with symptoms of PCOS (hirsutism, acne, difficulty conceiving). Do not accept severely painful or heavy periods as 'normal' — all significant menstrual symptoms have treatable causes.