Absent Periods

This symptom causes substantial anxiety in the sexually active woman: The first unexpectedly missed period suggests pregnancy; prolonged absence raises the concern that something is seriously amiss. In contrast, management is usually straightforward and helped by acknowledging the anxiety.

Published: 2nd August 2022 | Updated: 15th August 2022

Differential diagnosis

Common Diagnoses

  • Pregnancy
  • Physiological: Rapid Weight (10%–15%) Loss, and Severe Emotional Stress
  • Menopause (Including Premature Ovarian Failure)
  • Polycystic Ovary Syndrome (PCOS)
  • Drugs: Phenothiazines, Metoclopramide, Valproate, Cytotoxics

Occasional Diagnoses

  • Hypo- and Hyperthyroidism
  • Anorexia Nervosa
  • Excessive Exercise/Training
  • Severe Systemic Illness of any Kind
  • Contraception (Progestogen-only Pill, Long-Acting Reversible Contraception – Common Cause but Rarely Presented as a Symptom)

Rare Diagnoses

  • Adrenal Disorders: Addison’s Disease, Cushing’s Disease, Congenital Adrenal Hyperplasia
  • Sheehan’s Syndrome
  • Arrhenoblastoma, Bilateral Ovarian Tumours
  • Prolactinoma, other Pituitary Tumours
  • Rare Structural or Chromosomal Abnormalities (Primary Amenorrhoea)
  • Anterior Pituitary Failure (Simmonds’s Disease)

Ready reckoner

Key distinguishing features of the most common diagnoses

PregnancyWeight LossMenopauseDrugsPCOS
Breast TendernessYesNoNoNoNo
Hot FlushesNoNoYesNoNo

Possible investigations

Likely: Pregnancy test.

Possible: FBC, U&E, TFT, FSH/LH, testosterone, SHBG, prolactin, ultrasound.

Small Print: CT with or without other imaging.

  • Pregnancy test whatever contraception is used: Urinary HCG. Remember small false negative rate
  • FBC, U&E, TFT: To assess for general severe systemic illness, adrenal disorders and hypo- or hyperthyroidism.
  • FSH, LH, testosterone and SHBG: LH and testosterone may be high in PCOS (and SHBG normal or low), FSH very high in menopause.
  • Prolactin levels high in prolactinoma and with some drugs (e.g. phenothiazines)
  • Ultrasound useful to show multiple ovarian cyst formation and is a reliable check of pregnancy.
  • Specialist will arrange CT or similar imaging if prolactinoma suspected.

Top Tips

  • Amenorrhoea is common in young women, especially at times of stress; once pregnancy has been excluded and in the absence of any worrying symptoms or signs, only investigate if the problem persists beyond 6 months.
  • It is important to confirm a possible diagnosis of premature menopause, as the patient will require hormone-replacement therapy (HRT).
  • The same pathologies can cause both amenorrhoea and oligomenorrhoea, therefore take the same clinical approach to both.

Red Flags

  • Do not accept too readily the claim that there is ‘no chance of pregnancy’; if in any doubt, arrange a pregnancy test.
  • Consider anorexia – an emaciated body may be well hidden under baggy clothing, and the disease often presents with the absence of periods.
  • Early morning headache and visual disturbance associated with amenorrhoea suggest possible intracranial pathology – refer urgently
  • Before attributing amenorrhoea to weight loss, make sure that the weight loss itself hasn’t been caused by thyrotoxicosis.
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Website disclaimer

Pulse Reference is based on the best-selling book Symptom Sorter.

The experts behind Pulse Reference are Dr Keith Hopcroft who is the co-author of Symptom Sorter, a GP in Essex and Pulse’s editorial advisor and Dr Poppy Freeman, a GP in Camden and also a clinical advisor to Pulse.

This website is for clinical guidance only and cannot give definitive diagnostic information. Practitioners should work within the limits of their individual professional practice, seek guidance when necessary and refer appropriately.