Synopsis
Confirm whether ovulation occurs, investigate a suspected ovulatory disorder selectively, and use ovarian-reserve tests for the clinical question they can answer rather than as general fertility scores.
- Regular monthly menstrual cycles make ovulation likely, but NICE recommends mid-luteal serum progesterone during formal infertility investigation even when cycles are regular.
- Take progesterone about 7 days before the expected next period: day 21 fits a 28-day cycle, while a 35-day cycle is tested around day 28 and may require weekly repetition if very irregular.
- Basal body-temperature charts do not reliably confirm ovulation and should not replace biochemical assessment.
- In prolonged irregular cycles, measure FSH and LH to help classify ovulatory dysfunction; request prolactin only for ovulatory disorder, galactorrhoea or a pituitary tumour.
- Only test thyroid function when symptoms or signs suggest thyroid disease; indiscriminate thyroid and prolactin panels generate incidental results.
- Maternal age is the first predictor of the chance of spontaneous or IVF pregnancy.
- Do not use AMH to predict spontaneous conception. Use AMH or antral follicle count to predict ovarian response and inform assisted-conception decisions and counselling.
- Do not use FSH as a predictor of ovarian response or assisted-conception outcome under NG257; a reserve marker is not a test of oocyte quality or a guarantee of pregnancy.
Key red flags
Positive pregnancy testing with pelvic pain, bleeding, syncope or haemodynamic change requires urgent assessment for ectopic pregnancy.
Severe new headache, vomiting, visual-field loss, ophthalmoplegia, polyuria or polydipsia suggests sellar pathology and needs expedited endocrine and imaging review.
Rapid virilisation, voice deepening, clitoromegaly or markedly elevated androgens raises concern for an ovarian or adrenal androgen-secreting lesion.
Bradycardia, hypotension, syncope, electrolyte disturbance or severe restriction in someone with amenorrhoea indicates medical instability from low energy availability.
Hot flushes and menstrual disturbance before 40 with possible ovarian insufficiency require prompt confirmation and management for bone, cardiovascular and fertility consequences.
Investigation priorities
Provide biochemical evidence that ovulation occurred in the sampled cycle.
Management branches
A person with ovaries is undergoing fertility investigation.
- Document cycle length and variability, last period, pregnancy possibility, hormone use and symptoms of androgen excess, oestrogen deficiency, thyroid or pituitary disease.
- Offer mid-luteal progesterone even with regular cycles, scheduling it about 7 days before expected bleeding rather than using a fixed calendar day.
- If cycles are prolonged or unpredictable, sample later and repeat when needed, then investigate the cause of anovulation rather than repeatedly testing without a plan.