Infertility: Prevention, Diagnosis and When to See a Doctor

Around one in seven couples in the UK has difficulty conceiving, and in roughly half of cases a male factor plays a part. For people who train hard, diet aggressively or have used hormones, fertility deserves particular attention. Our editorial team sets out what raises the risk, what can be prevented, how the NHS investigates the problem and when it is time to ask for help.

What counts as infertility

Clinically, infertility is usually defined as failure to conceive after twelve months of regular unprotected intercourse. The National Institute for Health and Care Excellence (NICE) uses this definition in its fertility guideline and notes that most couples who have regular sex every two to three days will conceive within a year.

Infertility is not one disease but a symptom with many possible causes. In women the most common are ovulation disorders, blocked or damaged fallopian tubes and endometriosis. In men they include low sperm count, poor sperm motility or shape, blockages and hormonal problems. In a significant proportion of couples no single cause is found, which doctors describe as unexplained infertility.

It also helps to distinguish primary infertility, where a person has never conceived, from secondary infertility, where they have conceived before. Secondary infertility is common and can be just as distressing, yet people often delay seeking help because they assume previous success guarantees future fertility.

Age is the single biggest factor for women, with fertility declining gradually from the early thirties and more steeply after 35. Male fertility also declines with age, though more slowly and less predictably.

Risk factors you can influence

Many fertility risks are outside our control, but a surprising number are modifiable. A review by Sharma and colleagues of lifestyle factors and reproductive health highlighted body weight, smoking, alcohol, stress and environmental exposures as areas where change is realistic.

For athletes, the biggest red flag is often low energy availability. Women who train hard while eating too little can lose their periods, a sign that the reproductive axis has shut down to conserve energy. Men can experience falling testosterone and libido for the same reason.

Anabolic-androgenic steroids deserve special mention. Exogenous hormones signal the brain to stop releasing the hormones that drive sperm production. The result can be very low or absent sperm counts, shrinking testes and, in some men, persistent hypogonadism after stopping. Recovery is unpredictable and may take many months.

Sexually transmitted infections such as chlamydia and gonorrhoea can damage the fallopian tubes silently. Regular testing, which is free and confidential through NHS sexual health services, is a simple preventive measure.

Prevention in everyday life

There is no supplement that reliably prevents infertility, but a few evidence-based habits protect reproductive health. Folic acid before conception is recommended for women to reduce the risk of neural tube defects in the baby, not to improve fertility itself, but it is a standard part of preparing for pregnancy in the UK.

• Stop smoking and avoid recreational drugs, including cannabis.
• Keep alcohol low; the UK Chief Medical Officers advise that the safest approach for those trying to conceive is not to drink.
• Maintain a body weight in a healthy range and avoid crash diets.
• Eat enough to support your training, especially during heavy blocks.
• Use condoms with new partners and get tested for sexually transmitted infections.
• Discuss any regular medicines with your GP before trying to conceive.

Supplements marketed for "fertility boosting" often contain antioxidants, zinc, selenium or herbal extracts. Some have small studies behind them, but none replaces lifestyle measures or medical assessment. If you choose to take one, check it does not exceed safe upper levels for its ingredients.

Population data suggest sperm counts in some regions have fallen over recent decades, according to a widely cited meta-regression by Levine and colleagues. The causes are debated, but the finding underlines that male reproductive health deserves the same attention as female.

How infertility is diagnosed in the UK

The NHS pathway usually starts with the GP, who takes a history from both partners and arranges initial tests. Both partners should be assessed together, since problems on one side do not exclude problems on the other.

For women, the first steps typically include a blood test for progesterone in the second half of the cycle to confirm ovulation, along with other hormone tests where appropriate, chlamydia screening and, later, imaging of the uterus and tubes.

For men, the key investigation is semen analysis, performed according to World Health Organization laboratory standards. It assesses volume, sperm concentration, motility and morphology. Because results vary naturally, an abnormal result is usually repeated. Further hormone tests, such as testosterone, LH and FSH, help distinguish between production problems and blockages.

Referral to a specialist fertility clinic follows if initial tests are abnormal or the couple has not conceived within the expected time. Access to NHS-funded IVF depends on criteria set locally by integrated care boards, so eligibility differs across the country.

When to see a doctor

NICE advises seeing a GP if you have not conceived after a year of regular unprotected sex. You should seek help sooner in several situations.

• The woman is 36 or older.
• Periods are absent, very irregular or very painful.
• There is a known history of pelvic infection, endometriosis or abdominal surgery.
• The man has had testicular problems, undescended testes, surgery or chemotherapy.
• Either partner has used anabolic steroids or other hormones.
• There is a known reason that makes conception difficult.

Men who have used anabolic steroids should be open about it. Doctors are bound by confidentiality, and the information directly affects which tests are ordered and what treatment may help. Some cases require specialist andrology input.

Fertility problems can take a real toll on mental health and relationships. Counselling is part of NICE recommendations for couples undergoing investigation and treatment, and charities such as Fertility Network UK offer support.

Conclusions of the editorial team

Infertility is common, frequently treatable and very often shared between both partners. The earlier a problem is identified, the more options remain open.

Many risk factors, from smoking and alcohol to extreme dieting and hormone use, are within your control. Athletes in particular should take low energy availability and anabolic steroids seriously as threats to reproductive health.

If you have been trying for a year, or sooner if you are over 36 or have known risk factors, book an appointment with your GP and ask for both partners to be assessed.

You may also find our articles on the hypothalamic–pituitary–gonadal axis, on blood tests for hormone monitoring, and on relative energy deficiency in sport useful.

References

1. National Institute for Health and Care Excellence. Fertility problems: assessment and treatment. Clinical guideline CG156. London: NICE; 2013 (updated 2017).
2. World Health Organization. WHO laboratory manual for the examination and processing of human semen. 6th ed. Geneva: WHO; 2021.
3. Zegers-Hochschild F, Adamson GD, Dyer S, et al. The International Glossary on Infertility and Fertility Care, 2017. Fertil Steril. 2017;108(3):393–406.
4. Sharma R, Biedenharn KR, Fedor JM, Agarwal A. Lifestyle factors and reproductive health: taking control of your fertility. Reprod Biol Endocrinol. 2013;11:66.
5. Rahnema CD, Lipshultz LI, Crosnoe LE, et al. Anabolic steroid-induced hypogonadism: diagnosis and treatment. Fertil Steril. 2014;101(5):1271–1279.
6. Levine H, Jørgensen N, Martino-Andrade A, et al. Temporal trends in sperm count: a systematic review and meta-regression analysis. Hum Reprod Update. 2017;23(6):646–659.