Personal Fertility Plans for Every Couple

The most informative figures come from couples who were timing intercourse deliberately, which makes them a best case rather than an average. Gnoth and colleagues followed 346 women using natural family planning methods to conceive from their first cycle onwards. The cumulative probability of conception was:

• 38% had conceived after one cycle
• 68% after three cycles
• 81% after six cycles
• 92% after twelve cycles
• 10.4% of 346 women did not conceive at all

The authors' conclusion is the part worth carrying: most couples conceive within six cycles with timed intercourse, and thereafter every second couple is probably either subfertile or infertile. Read that as a reason to start asking questions at six months of well-timed trying rather than as a deadline - these were couples making optimal use of their fertility, so real-world curves are flatter.

What this article deliberately does not do is give you a referral threshold by age. The thresholds in wide circulation come from a national guideline we could not retrieve at the time of writing, and quoting a rule from memory is exactly how wrong numbers spread. Your own clinician's threshold, and the reason for it, is a fair thing to ask about directly.

Unexplained infertility is a diagnosis of exclusion. That has a blunt consequence for planning: the label is only as good as the work-up behind it, and ESHRE's 2023 guideline states plainly that a consensual standardisation of that work-up is still lacking. Two couples given the same diagnosis at two clinics may have had different things checked.

So the first question a plan should answer is not which treatment, but what has actually been excluded. The three domains any work-up has to cover are ovulation, tubal and uterine anatomy, and semen. This site covers each in detail separately rather than repeating it here:

• Fertility tests for women: what each one checks, and when
• Fertility tests to do together
• Semen analysis: what it reveals about fertility
• Male vs female infertility: who gets tested first

On the male side, the AUA and ASRM guideline frames the evaluation as the assessment of the male in an infertile couple - history and physical examination first, then diagnostic testing where indicated. It also records something that rarely reaches the patient: detecting male infertility increases the risk of subsequent health problems for that man. A semen analysis is partly a general health test, which is an argument for doing it early rather than after the woman has been through months of investigation.

Less mechanically than most plans assume, because the reference values are distributions rather than pass marks.

The 5th centile values behind the WHO sixth edition come from a cohort of more than 3,500 men in 12 countries whose partners conceived within twelve months:

• Sperm concentration 16 million per mL, and total sperm number 39 million per ejaculate, in that cohort
• Total motility 42% and progressive motility 30%, in the same cohort
• Normal forms 4%, semen volume 1.4 mL and vitality 54%, from that same cohort

The authors of that dataset state directly that these do not represent distinct limits between fertile and subfertile men, and the sixth edition itself dropped reference thresholds in favour of “decision limits” without proposing any.

Practical consequences for a plan:

• One result just below a 5th centile is a reason to repeat the test, not to escalate treatment
• A semen analysis reflects sperm produced over roughly the preceding two months, so it dates from before any recent change
• Numbers well below the range, or a repeatedly abnormal result, change the plan; a borderline one usually should not

For unexplained infertility, ESHRE deems the first-line treatment to be IUI in combination with ovarian stimulation. Not IVF. That ordering is worth knowing before a first consultation, because the gap between it and what gets offered is where a lot of money goes.

The evidence under the whole ladder is weak, and saying so is not hedging. Cochrane's 2023 review of IVF for unexplained subfertility found:

• Versus expectant management: uncertain whether IVF improves live birth or clinical pregnancy - two RCTs, 86 women, very low-quality evidence
• Versus unstimulated IUI: IVF may improve live birth (OR 2.47, 95% CI 1.19 to 5.12) - two RCTs, 156 women, low-quality evidence
• Assuming a 16% live birth rate with unstimulated IUI, the rate with IVF would lie somewhere between 18.5% and 49%

And of ESHRE's 52 recommendations on unexplained infertility, none rest on high-quality evidence: one on moderate-quality, nine on low and 31 on very low. This is a field where the sequence is conventional rather than proven, so a plan that commits to a review point is worth more than one that commits to a protocol.

Sometimes the answer is testing, timing or a simpler treatment. ASRM's committee opinion on optimising natural fertility exists precisely for couples attempting conception who have no evidence of infertility, and that is a real category - not everyone presenting at a clinic needs a cycle.

These are questions to put to a clinician, not things to decide alone. A plan that answers them is auditable; one that does not is a sales sequence.

• What has been excluded so far, and what has not been checked yet
• Which single result would change the plan, and in which direction
• How many attempts at this step before the plan is reviewed, agreed in advance rather than after a failed cycle
• What the denominator is on any success figure quoted - per cycle started or per transfer, and for which age band and diagnosis
• What the next step would be if this one does not work, and what it costs
• Which parts are evidence-based and which are the clinic's preference - a fair question, and ESHRE's own quality ratings make it a reasonable one
• When you will both sit down and decide whether to continue

Deciding the number of attempts in advance is the item most often skipped and the one that most changes how the months feel. It is easier to agree on two stimulated IUI cycles before starting than to decide after the second has failed.

Reasonably established:

• Most couples with timed intercourse conceive within six cycles, and 92% within twelve, in a best-case cohort of 346 women
• Unexplained infertility is a diagnosis of exclusion, and there is no agreed standard for the work-up behind it
• ESHRE places stimulated IUI ahead of IVF as first-line treatment for unexplained infertility
• Semen reference values are distributions from men who conceived, not a boundary between fertile and infertile

Not established:

• That a personalised plan, as such, produces more live births than standard care. No retrieved study has tested that, and this article makes no such claim
• The optimal moment to escalate from one step to the next. The Cochrane comparisons rest on 86 and 156 women
• That stress causes infertility, or that reducing it improves conception. No retrieved source here supports it - support is worth having because treatment is hard
• That any lifestyle change or supplement substitutes for completing the work-up
• Referral thresholds by age, which are not asserted here because the guideline stating them could not be retrieved and verified

The honest summary: the value of a plan is not that it is personalised. It is that it names what has been excluded, fixes a review point before the emotional cost of a failed cycle arrives, and states which of its steps are supported by evidence and which are convention.

• Dealing with unexplained infertility
• IUI vs IVF for couples trying to conceive
• IVF cost and insurance in India: what the law says
• Common male fertility tests explained
• How long to abstain before fertility testing