Fertility Tests Every Couple Should Know About — and When to Ask for Each One

Most couples begin a fertility investigation without knowing what tests exist, what each one measures, or why the order and timing of testing matters. The result is often months of incomplete information — testing one partner sequentially when both should be assessed simultaneously, or missing a key test because nobody thought to order it.

This guide maps out the core fertility investigations for both partners: what each test measures, what the results tell you, and when to ask for it.

For Women: The Core Fertility Tests

AMH (Anti-Müllerian Hormone)

What it measures: Ovarian reserve — the quantity of eggs remaining in the ovaries. AMH is produced by small follicles and reflects how many eggs are available to be recruited each cycle.

What the result tells you: A high AMH suggests good ovarian reserve and a strong expected response to ovarian stimulation. A low AMH suggests diminished reserve — a narrower window for fertility treatment and, in some interpretations, a reason to act sooner. Critically, AMH does not predict natural conception ability — only how the ovaries would respond to IVF stimulation.

Timing: Can be tested at any point in the cycle. No specific day required.

FSH and LH (Day 2–3 of Cycle)

What they measure: FSH (follicle-stimulating hormone) reflects how hard the pituitary gland is working to recruit eggs. Elevated FSH on day 2–3 suggests diminished ovarian reserve. LH together with FSH gives a picture of the hormonal signalling that drives the cycle.

What the result tells you: High FSH (above approximately 10–12 IU/L on day 2–3) may indicate reduced ovarian reserve. The FSH/LH ratio is also informative — a high ratio can be seen in PCOS.

Timing: Specifically on cycle day 2 or 3. Results from other days are less informative.

Thyroid Panel (TSH, T3, T4)

What it measures: Thyroid function. Both hypothyroidism (underactive) and hyperthyroidism (overactive) can interfere with ovulation, menstrual regularity, and implantation.

What the result tells you: TSH above 2.5 mIU/L may be worth treating when trying to conceive, even if technically "within normal range" — fertility-focused thyroid thresholds are tighter than general population ranges.

Timing: Any time in the cycle.

Prolactin

What it measures: The level of prolactin, a hormone produced by the pituitary. Elevated prolactin can suppress ovulation and cause irregular or absent periods.

What the result tells you: If elevated, the cause needs investigation (stress, medications, or a small pituitary growth called a prolactinoma). Most causes are treatable.

Timing: Any time; best tested in the morning, fasting, and without recent vigorous exercise (all of which elevate prolactin transiently).

HSG (Hysterosalpingography)

What it measures: The patency (openness) of the fallopian tubes and the shape of the uterine cavity.

What the result tells you: Whether the tubes are open or blocked, and whether the uterus has structural abnormalities. Essential for understanding whether eggs and sperm can meet through the natural route.

Timing: Typically performed on cycle days 7–10, after the period has ended and before ovulation.

Pelvic Ultrasound

What it measures: The ovaries (appearance, antral follicle count, any cysts), the uterus (shape, fibroid presence, endometrial lining thickness), and any pelvic abnormalities.

What the result tells you: Antral follicle count provides a visual correlate of ovarian reserve alongside AMH. Fibroids, polyps, or a bicornuate uterus may affect implantation.

Timing: Ideally cycle days 2–5 for antral follicle count assessment.

Mid-Luteal Progesterone (Day 21 or 7 Days Before Expected Period)

What it measures: Whether ovulation occurred this cycle, and whether progesterone production is adequate.

What the result tells you: A level above approximately 16–30 nmol/L (depending on the lab) confirms ovulation. Low progesterone may indicate inadequate luteal phase support.

Timing: Approximately 7 days before your expected next period (day 21 in a 28-day cycle, day 14 in a 21-day cycle).

For Men: The Core Fertility Tests

Semen Analysis

What it measures: Count (total sperm per ejaculate), concentration (sperm per millilitre), motility (percentage moving progressively), morphology (percentage of normal-shaped sperm), volume, and pH.

What the result tells you: A comprehensive picture of sperm production and function. Any parameter outside the WHO reference ranges warrants attention — and the combination of parameters matters as much as any individual number.

Timing: After 2–5 days of abstinence. Longer abstinence reduces motility; shorter reduces count. The sample should be analysed within an hour of collection.

Sperm DNA Fragmentation Index (DFI)

What it measures: The percentage of sperm with damaged DNA — fragmented genetic material that may affect fertilisation and embryo development.

What the result tells you: High fragmentation (above approximately 25–30%) is associated with reduced fertilisation rates and higher miscarriage rates, even when standard semen parameters are normal. Particularly relevant in couples with unexplained infertility or recurrent miscarriage.

Timing: Same conditions as semen analysis.

The Most Important Practical Point: Test Both Partners Simultaneously

The single most impactful improvement most couples can make to their investigation process is arranging male and female testing in parallel from the start.

Sequential testing — investigating the woman first, then investigating the man only if female results are clear — is common and wastes months. Male factor is involved in approximately 40–50% of fertility cases. Testing both simultaneously gives you a complete picture in one investigation cycle rather than two.

A free fertility assessment will help you map which of these tests are most relevant to your specific situation — so you ask for the right things, in the right order, from the start.

Your Testing Roadmap — Step by Step

1. For women: AMH, Day 2–3 FSH/LH, thyroid panel, prolactin — start here
2. For women: schedule HSG for days 7–10 of the same or next cycle
3. For women: pelvic ultrasound for antral follicle count and uterine structure
4. For women: mid-luteal progesterone (day 21 or 7 days before expected period)
5. For men: semen analysis with 2–5 days abstinence — arrange at the same time as female tests
6. For men: consider adding sperm DNA fragmentation if standard analysis is borderline or normal but conception has not occurred
7. Review all results together with a specialist who can contextualise them for your specific situation