Differential Diagnosis

Common Diagnoses

  • Unexplained (27%)
  • Defective Sperm (24% – May be Various Underlying Causes)
  • Anovulatory Cycles/Defective Ovulation (21%)
  • Fallopian Tube Blockage (14%)
  • Endometriosis (6%)

Occasional Diagnoses

  • Hostile Cervical Mucus
  • PCOS
  • Other Causes of Amenorrhoea or Hypomenorrhoea (see Absent Periods)
  • Uterine Fibroids, Polyp
  • Cervical Problems: Inflammation, Polyps, Stenosis
  • Systemic Illness, e.g. Anaemia, Thyroid Disorders

Rare Diagnoses

  • Congenital Uterine, Vaginal, Fallopian or Ovarian Malformation or Absence
  • Sexual Dysfunction
  • Adrenocortical Tumours
  • Chromosomal Abnormalities: Turner’s Syndrome (XO), Super-Female (XXX)
  • Endometrial Tuberculosis

Ready Reckoner

Key distinguishing features of the most common diagnoses

UnexplainedDefective SpermAnovulation/ Defective OvulationTubal Blockage Endometriosis
History of STDNoPossibleNoYesNo
Abnormal Pelvic ExaminationNoNoNoPossiblePossible
Regular CycleYesYesPossibleYesYes

Possible Investigations

Likely:Semen analysis, serum progesterone 7 days before anticipated onset of period.

Possible:If menstrual irregularity/amenorrhoea/unwell – FBC, FSH, LH, prolactin, TFT, U&E, testosterone, SHBG. In secondary care: Ovarian/uterine ultrasound.

Small Print:Laparoscopy and dye, hysterosalpingogram. In the male: Further investigation of sperm problems, e.g. FSH, LH, testosterone, testicular ultrasound.

  • Semen analysis: May need repeating if first test sub-optimal.
  • Serum progesterone 7 days before anticipated onset of period: To check for ovulation.
  • FBC, FSH, LH, prolactin, TFT, U&E, testosterone, SHBG: To check for underlying pathology if female is unwell or has menstrual problems.
  • Ovarian and uterine ultrasound: To exclude structural abnormalities. Can be extended to visualise ovarian follicle development and ovulation.
  • Laparoscopy and dye, hysterosalpingogram: To check for tubal patency.
  • Male FSH, LH and testosterone: To check for endocrine causes of sperm production failure.
  • Testicular ultrasound: If anatomical abnormalities found on examination, e.g. varicocoele.

Top Tips

  • Adopt an optimistic approach whenever possible. A surprising number of couples conceive successfully as soon as preliminary investigations are initiated!
  • Don’t overlook health promotion opportunities – especially female rubella status and advice about taking folic acid.
  • Ensure you treat the couple rather than the individuals. Infertility management requires much cooperation and motivation.
  • In primary care, hormone tests (other than progesterone) are not necessary if the periods are normal.

Red Flags

  • Infertility will only very rarely be the presenting symptom of serious pathology. However, there are circumstances where it is important to act promptly in terms of investigation or referral, such as:
  • if the female is over the age of 35; has amenorrhoea; has a history of previous pelvic surgery or PID; has any abnormality on pelvic examination
  • or if the male has a history of urogenital problems or STD; has a varicocele.

Published: 2nd August 2022 Updated: 12th February 2024

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