Infertility signs, causes, testing and when to get help

Trying to conceive can be exciting, but when pregnancy doesn’t happen as quickly as expected, it’s natural to feel worried, frustrated, or uncertain about what to do next.

Infertility affects millions of people and can happen for many different reasons, including hormone imbalances, ovulation problems, sperm quality, age, and underlying health conditions. 

Around 1 in 6 people globally experience infertility at some point in their lives. The reassuring news is that fertility testing and medical support may help identify possible causes and provide clarity about your reproductive health.

In this guide, we explore:

• What is infertility?
• Signs of infertility
• Common causes of infertility
• Can lifestyle affect fertility?
• How is infertility diagnosed?
• When should you consider fertility testing?
• Can infertility be treated?
• Unexplained infertility
• Fertility and emotional wellbeing
• Understanding your fertility health
• Frequently asked questions about infertility

What is infertility?
 

Infertility is a reproductive health condition where pregnancy doesn’t happen despite regular unprotected intercourse.

According to the World Health Organization (WHO), infertility affects millions of people globally and can impact both physical and emotional wellbeing.

Infertility may be:

• Primary infertility: where pregnancy has never occurred
• Secondary infertility: difficulty conceiving after a previous pregnancy

Doctors generally recommend fertility investigations after:

• Twelve months of trying to conceive if under 35
• Six months if over 35
• Earlier if there are known fertility concerns such as irregular periods, PCOS, endometriosis, low sperm count, or previous miscarriage

Signs of infertility
 

The most common sign of infertility is difficulty becoming pregnant.

However, some people may also experience symptoms linked to hormone imbalances or underlying reproductive conditions.

Signs of infertility in men

Male infertility often causes no obvious symptoms, but some men may experience:

• Reduced libido
• Erectile dysfunction
• Pain or swelling in the testicles
• Low energy levels
• Reduced muscle mass
• Hormonal symptoms such as gynecomastia (enlarged breast tissue)

Male factor infertility contributes to around half of infertility cases, either alone or alongside female fertility factors.

Signs of infertility in women

Potential symptoms may include:

• Irregular or absent periods
• Very painful periods
• Heavy bleeding
• Spotting between periods
• Difficulty tracking ovulation
• Recurrent miscarriage
• Pelvic pain
• Excess facial hair or acne (which may suggest PCOS)
• Hot flushes or vaginal dryness

Common causes of infertility
 

Infertility can have many different causes, and sometimes several factors may be involved at once.

Four common causes of male infertility

1. Low sperm count or poor sperm quality

Sperm health is one of the biggest contributors to male fertility.

Important sperm parameters include:

• Sperm count
• Motility (movement)
• Morphology (shape)
• DNA integrity

Male fertility can be affected by a wide range of factors, including hormone imbalances, lifestyle habits, age, underlying medical conditions, and sperm health. Smoking, alcohol intake, stress, poor sleep, obesity, excessive heat exposure, and anabolic steroid use may all impact sperm production and quality. 

For more on this topic, head over to our blog on how to improve male fertility and sperm quality.

2. Hormone imbalances

Hormones play an essential role in sperm production.

Low testosterone or abnormalities in hormones may affect fertility, such as:

• FSH
• LH
• Prolactin
• Thyroid hormones

A male fertility hormone blood test may help investigate potential hormone-related causes.

3. Varicocele

A varicocele is an enlargement of the veins within the scrotum, similar to varicose veins that can develop in the legs. Varicoceles are relatively common and may affect blood flow and temperature regulation around the testicles, which can sometimes impact sperm production, sperm quality, and testosterone levels.

Some men with a varicocele experience no symptoms at all, while others may notice:

• a dull ache or heaviness in the scrotum 
• swelling or visible enlarged veins 
• discomfort after standing or exercising 
• fertility problems 

Varicoceles are one of the more common potentially treatable causes of male infertility. If a varicocele is suspected, a GP or fertility specialist may recommend a physical examination, ultrasound scan, semen analysis, or hormone blood tests to assess sperm health and reproductive hormones.

Treatment isn’t always necessary, but in some cases surgery or other procedures may be considered if fertility, pain, or testicular function are affected.

4. Nutrient deficiencies 

Research suggests that nutrients involved in hormone production, antioxidant protection, and sperm development may play an important role in male reproductive health. Low levels of some vitamins and minerals have been associated with reduced sperm count, poor motility (movement), abnormal sperm shape, and increased oxidative stress, which can damage sperm cells.

Nutrients commonly linked to male fertility include:

• Zinc — important for testosterone production and sperm development 
• Vitamin D — may support testosterone levels and sperm motility 
• Selenium — helps protect sperm from oxidative damage 
• Folate (vitamin B9) — involved in DNA synthesis and sperm production 
• Vitamin B12 — linked to sperm count and motility 
• Omega-3 fatty acids — may support sperm membrane health 
• Coenzyme Q10 — acts as an antioxidant and may improve sperm motility 

However, evidence for fertility supplements is mixed, and taking high doses of vitamins will not necessarily improve fertility if deficiencies are not present.

Lifestyle factors such as smoking, alcohol intake, poor sleep, obesity, stress, and excessive heat exposure often have a larger overall impact on sperm health.

Before considering supplements or treatment, healthcare professionals may recommend: 

• Semen analysis 
• Hormone blood testing 
• Nutritional assessment 
• Lifestyle review

Four common causes of female infertility

1. Ovulation disorders

Problems with ovulation are one of the most common causes of female infertility.

Conditions affecting ovulation include:

• Polycystic ovary syndrome (PCOS)
• Hypothalamic dysfunction
• Premature ovarian insufficiency
• Thyroid disorders
• Hyperprolactinaemia

Hormone blood tests may help assess ovulation, ovarian reserve, and overall reproductive hormone balance.

If you’d like to learn more about the hormones involved in fertility and pregnancy, read our guides to pregnancy hormones, AMH and fertility, and how thyroid health can affect fertility and pregnancy.

2. Age-related fertility decline

Female fertility naturally changes with age as both egg quantity and egg quality decline over time. Although fertility varies from person to person, these changes tend to become more noticeable after the age of 35.

Anti-Müllerian hormone (AMH) testing may help provide insight into ovarian reserve and reproductive hormone health. You can read more about how age may affect your chances of conceiving in our guide to age and fertility.

3. Endometriosis

Endometriosis is a condition where tissue similar to the lining of the womb grows outside the uterus, commonly affecting the ovaries, fallopian tubes, and pelvic lining.

It may affect fertility in several ways, including:

• Disrupting ovulation 
• Affecting egg quality 
• Causing inflammation within the pelvis 
• Damaging the fallopian tubes 
• Affecting implantation 
• Altering pelvic anatomy through scar tissue or adhesions 

Symptoms can vary from person to person, but may include:

• Painful periods 
• Chronic pelvic pain 
• Pain during or after sex 
• Pain when going to the toilet 
• Heavy periods 
• Fatigue 
• Difficulty conceiving 

Some people with endometriosis have no symptoms at all and only discover the condition during fertility investigations. 

If endometriosis is suspected, a GP or fertility specialist may recommend imaging scans, hormone testing, or referral for further assessment.

4. Fallopian tube problems

The fallopian tubes play an important role in fertility by helping the sperm reach the egg and transporting a fertilised egg to the uterus. If one or both tubes become blocked or damaged, this process can be disrupted, making it more difficult to conceive naturally.

Fallopian tube problems may be caused by:

• Pelvic inflammatory disease (PID) 
• Previous abdominal or pelvic surgery 
• Endometriosis 
• Sexually transmitted infections (STIs) 
• Scar tissue or adhesions 

In some cases, blocked fallopian tubes may not cause any noticeable symptoms and are only discovered during fertility investigations. 

Depending on the suspected cause, a fertility specialist may recommend imaging tests, such as a hysterosalpingogram (HSG) or ultrasound scan, to assess the fallopian tubes and reproductive organs.

Can lifestyle affect fertility?
 

Research suggests that lifestyle factors can affect fertility in both men and women by influencing hormone balance, ovulation, sperm production, egg quality, and overall reproductive health.

Factors that may negatively affect fertility include:

• Smoking 
• Excessive alcohol intake 
• Poor sleep 
• Chronic stress 
• Obesity or being underweight 
• Recreational drug use 
• Anabolic steroid use 
• Poor diet 
• Excessive heat exposure around the testicles 

In men, lifestyle factors may affect sperm count, motility, morphology, and testosterone levels. Frequent heat exposure from hot tubs, saunas, tight clothing, or prolonged laptop use on the lap may also affect sperm production.

In women, smoking, significant weight changes, stress, and hormone imbalances may affect ovulation and menstrual cycles.

While lifestyle changes cannot treat every cause of infertility, improving sleep, nutrition, exercise, stress management, and overall health may help support reproductive health and fertility outcomes.

How is infertility diagnosed?
 

It’s really important that both partners are assessed together to investigate infertility.

Fertility investigations may involve:

• Hormone blood tests
• Ovulation testing
• Ultrasound scans
• Semen analysis
• Thyroid testing
• Imaging procedures
• Medical history review

When should you consider fertility testing?
 

You may want to consider fertility testing if you:

• Have been trying to conceive for 12 months (or six months if over 35) 
• Have irregular or absent periods 
• Have PCOS or endometriosis 
• Have experienced recurrent miscarriage 
• Have symptoms of low testosterone 
• Have concerns about sperm quality 
• Are preparing for IVF treatment 
• Want insight into your hormone health before trying to conceive 

Fertility testing may help identify hormone imbalances, ovulation problems, reduced ovarian reserve, or issues affecting sperm health.

If you’re unsure where to start, our guide to choosing the right fertility test explains the different fertility blood tests available for men and women, including hormone testing, ovarian reserve testing, and male fertility hormone profiles.

At-home blood testing may also provide useful insight into reproductive hormone health before speaking to a GP or fertility specialist.

Can infertility be treated?
 

Fertility treatment depends on the underlying cause.

Options may include:

• Lifestyle changes
• Ovulation induction medications
• Hormone treatment
• Surgery
• IVF (in vitro fertilisation)
• ICSI (intracytoplasmic sperm injection)
• Fertility preservation

In some cases, improving overall health, managing hormone imbalances, reducing smoking or alcohol intake, improving sleep, or optimising weight may help improve fertility.

Unexplained infertility
 

In some cases, fertility tests do not identify a clear cause. This is sometimes referred to as unexplained infertility.

Even when routine testing appears normal, subtle hormonal, egg quality, sperm quality, genetic, or implantation-related factors may still contribute.

Fertility and emotional wellbeing
 

Trying to conceive can be emotionally challenging, especially when things aren’t going to plan. Feelings of stress, frustration, anxiety, sadness, and isolation are common and can affect both mental wellbeing and relationships.

If you’re struggling, it may help to talk openly with people you trust, whether that’s a partner, friend, family member, colleague, GP, fertility specialist, or counsellor. Some people also find support groups and online fertility communities reassuring during their fertility journey.

You may also find organisations such as Fertility Network UK and NHS fertility support services helpful, alongside our guides to age and fertility, how long it can take to get pregnant, and improving male fertility and sperm quality.

Understanding your fertility health
 

Infertility can affect both men and women and may be linked to hormonal, medical, lifestyle, or age-related factors.

Fertility testing may help provide insight into reproductive health and identify possible causes affecting conception.

Hormone blood tests can offer valuable information about ovulation, ovarian reserve, sperm production, testosterone levels, and thyroid function.

If you are concerned about fertility, speaking to a healthcare professional or fertility specialist may help you understand the next steps.

Frequently asked questions about infertility
 

What is infertility?

Infertility is usually defined as not becoming pregnant after 12 months of regular unprotected sex.

What are the signs of infertility?

Potential signs may include irregular periods, absent ovulation, recurrent miscarriage, erectile dysfunction, or difficulty conceiving.

Can infertility be treated?

Yes. Treatment depends on the underlying cause and may include hormone treatment, lifestyle changes, fertility medication, or assisted reproductive techniques such as IVF.

When should I get a fertility test?

Most couples are advised to seek fertility testing after 12 months of trying to conceive, or after six months if the woman is over 35.

Can men be infertile too?

Yes. Male factor infertility contributes to around half of infertility cases.

What hormones are checked in fertility testing?

Common fertility hormones include:

• AMH
• FSH
• LH
• Progesterone
• Oestradiol
• Testosterone
• Prolactin
• Thyroid hormones

 

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