Absent or infrequent periods
Reproductive health
Clinic
The first question
Primary or secondary, and is she pregnant?
- 01
Define
Primary: no menses by 15 (or by 13 with no secondary sexual characteristics). Secondary: 3 months without menses after regular cycles, or 6 months after irregular ones.
- 02
Pregnancy test
The commonest cause of secondary amenorrhoea.
- 03
The four compartments
Outflow tract, ovary, pituitary, hypothalamus: history, examination and a small set of tests sort them.
- 04
Treat the cause and protect the bones and endometrium
Oestrogen replacement in hypo-oestrogenic states; endometrial protection in anovulatory ones.
Where it is
Each opens the structure on the 3D pelvis.
History that discriminates
- Menstrual history, pubertal milestones
- Weight change, exercise, eating, stress
- Hirsutism, acne, galactorrhoea, headaches, visual symptoms
- Hot flushes
- Medications (antipsychotics, contraception)
- Chemotherapy, radiotherapy, uterine surgery
- Family history of early menopause
Examination that discriminates
- BMI, secondary sexual characteristics, Tanner stage
- Hirsutism, acne, acanthosis nigricans
- Thyroid, visual fields, galactorrhoea
- External genitalia; hymen and vagina in primary amenorrhoea
Investigations
- hCG
- FSH, LH, oestradiol, prolactin, TSH
- Testosterone, free androgen index, 17-hydroxyprogesterone if hyperandrogenic
- Pelvic ultrasound
- Karyotype in primary amenorrhoea with raised FSH
- MRI pituitary for raised prolactin or headache and visual symptoms
- AMH if premature ovarian insufficiency is suspected
The differential
| Diagnosis | Favours | Against | Urgency |
|---|---|---|---|
| Pregnancy | Positive test | Negative test | routine |
| PCOS | Oligomenorrhoea with hyperandrogenism, normal FSH | Hypo-oestrogenism | routine |
| Functional hypothalamic amenorrhoea | Low weight, high exercise, stress, low FSH and LH, low oestradiol | Raised FSH | routine |
| Hyperprolactinaemia | Galactorrhoea, raised prolactin, medications, pituitary lesion | Normal prolactin | routine |
| Premature ovarian insufficiency | Hot flushes, raised FSH twice, low oestradiol, under 40 | Normal FSH | routine |
| Thyroid disease | Abnormal TSH | Normal TSH | routine |
| Outflow obstruction or absence (imperforate hymen, transverse septum, Müllerian agenesis) | Primary amenorrhoea with normal development, cyclical pain, a bulging hymen, absent uterus on scan | Prior menses | routine |
| Asherman's syndrome | Amenorrhoea after uterine surgery or infection, normal hormones | No uterine instrumentation | routine |
| Turner syndrome | Primary amenorrhoea, short stature, raised FSH, 45,X | Normal karyotype | routine |
Pitfalls this pathway refuses
- Diagnosing PCOS in an adolescent on ultrasound
- Missing an eating disorder
- Not replacing oestrogen in a young woman with ovarian insufficiency