Fertility, and when to get it checked

Couples trying to conceive are frequently told to relax and keep trying, which is reasonable advice for a period and becomes harmful past it.

The baseline numbers

Among couples with no fertility problem, a majority conceive within six months and the large majority within a year of regular unprotected sex.

Which is why the standard definition of infertility is failure to conceive after twelve months, and after six months where the woman is over thirty-five.

Earlier assessment is appropriate where there is a known reason: irregular or absent periods, previous pelvic infection or surgery, endometriosis, undescended testes, chemotherapy, or known conditions affecting either partner.

The timing that matters

The fertile window is the five days before ovulation and the day of ovulation itself, since sperm survive several days and the egg does not.

Sex every two to three days throughout the cycle achieves the same outcome as attempting to time ovulation precisely, and is considerably less stressful.

Ovulation prediction kits detect the luteinising hormone surge and identify the window prospectively; basal body temperature confirms ovulation retrospectively and is therefore less useful for timing.

Cycle apps predicting from calendar data alone are unreliable, since ovulation timing varies more than most people assume.

Assessment

What is generally offered, and it involves both partners from the start.

For the man: a semen analysis, which is straightforward, and which is the single highest-yield first test given that a male factor contributes in roughly half of cases.

It is frequently deferred while the woman undergoes extensive investigation, which is a recognised and avoidable problem.

An abnormal result is repeated, since variation is considerable.

For the woman: confirmation of ovulation by mid-luteal progesterone; assessment of ovarian reserve using anti-Müllerian hormone and antral follicle count; thyroid and prolactin where indicated; rubella immunity; and assessment of tubal patency by specialist imaging.

Ovarian reserve tests indicate the likely response to stimulation rather than predicting natural conception, which is a distinction frequently lost in direct-to-consumer testing.

What affects fertility

Age is the dominant factor for women, with a decline that accelerates from the mid-thirties and is driven by egg quality as well as number.

Male fertility declines more gradually and is not exempt, with paternal age associated with reduced conception rates and some pregnancy outcomes.

Smoking, in both partners, with clear evidence of harm.

Weight at either extreme, affecting ovulation and semen parameters.

Alcohol, with heavier consumption clearly implicated.

Anabolic steroids and testosterone, which suppress sperm production substantially and which are a frequently missed cause in men attending fertility clinics.

Heat exposure for men, though the effect is modest.

Certain medications and occupational exposures.

And untreated infections, particularly chlamydia, which is a leading preventable cause of tubal damage.

What is oversold

The area is heavily commercialised.

Most supplements marketed for fertility have limited evidence; folic acid before conception is the clear exception and is genuinely important for preventing neural tube defects.

Vitamin D and some antioxidants have modest evidence in specific circumstances.

Add-on treatments offered alongside IVF have been assessed by regulators in some countries and rated poorly for evidence, while being sold at considerable cost.

Ovarian reserve testing sold as a general indicator of how long someone has to conceive overstates what it can tell an individual.

Treatment

Depends entirely on the cause.

Ovulation induction where ovulation is the problem, with letrozole favoured in current guidance for polycystic ovary syndrome.

Surgery for some tubal and uterine problems and for endometriosis.

Intrauterine insemination in selected situations.

IVF, with or without intracytoplasmic sperm injection for male factor.

Donor gametes and surrogacy, with legal frameworks varying enormously between countries.

Success rates depend heavily on age and cause, and clinics are required in some jurisdictions to publish them in comparable form, which is worth seeking out.

The psychological load

Consistently underestimated.

Studies of couples in fertility treatment report levels of distress comparable to those with serious medical conditions.

Sex frequently becomes scheduled, functional and unwanted, which is one of the most commonly reported harms and which is worth protecting against deliberately.

Counselling is available through most fertility services and is worth using early rather than at crisis point.

And the decision about when to stop is one of the hardest, is rarely discussed in advance, and is easier if it has been thought about before the first cycle rather than after the fourth.

General information only, not medical advice. Consult a qualified clinician about fertility concerns — both partners should be assessed.