Infertility is when a couple cannot get pregnant (conceive) despite having regular unprotected sex.

Around 1 in 7 couples may have difficulty conceiving.

About 84% of couples will conceive naturally within a year if they have regular unprotected sex (every 2 or 3 days).

For couples who have been trying to conceive for more than 3 years without success, the likelihood of getting pregnant naturally within the next year is 1 in 4, or less.

Getting help

Some people get pregnant quickly, but for others it can take longer. It’s a good idea to see a Doctor if you have not conceived after a year of trying.

Women aged 36 and over, and anyone who’s already aware they may have fertility problems, should see their Doctor sooner.

They can check for common causes of fertility problems and suggest treatments that could help.

Infertility is usually only diagnosed when a couple have not managed to conceive after a year of trying.

There are 2 types of infertility:

• primary infertility – where someone who’s never conceived a child in the past has difficulty conceiving
• secondary infertility – where someone has had 1 or more pregnancies in the past, but is having difficulty conceiving again

Treating infertility

Fertility treatments include:

• medical treatment for lack of regular ovulation
• surgical procedures such as treatment for endometriosis, repair of the fallopian tubes, or removal of scarring (adhesions) within the womb or abdominal cavity
• assisted conception such as intrauterine insemination (IUI) or IVF

The treatment offered will depend on what’s causing the fertility problems.

Some treatments for infertility, such as IVF, can cause complications.

For example:

• multiple pregnancy – if more than 1 embryo is placed in the womb as part of IVF treatment there’s an increased chance of having twins; this may not seem like a bad thing, but it significantly increases the risk of complications for you and your babies
• ectopic pregnancy – the risk of having an ectopic pregnancy is slightly increased if you have IVF

What causes infertility?

There are many possible causes of infertility, and fertility problems can affect either partner. But in a quarter of cases it is not possible to identify the cause.

Common causes of infertility include:

• lack of regular ovulation (the monthly release of an egg)
• poor quality semen
• blocked or damaged fallopian tubes
• endometriosis – where tissue that behaves like the lining of the womb (the endometrium) is found outside the womb

Risk factors

There are also several factors that can affect fertility.

These include:

• age – fertility declines with age
• weight – being overweight or obese (having a BMI of 30 or over) reduces fertility; in women, being overweight or severely underweight can affect ovulation
• sexually transmitted infections (STIs) – several STIs, including chlamydia, can affect fertility
• smoking – can affect fertility: smoking (including passive smoking) affects your chance of conceiving and can reduce semen quality; read more about quitting smoking
• alcohol – the safest approach is not to drink alcohol at all to keep risks to your baby to a minimum. Drinking too much alcohol can also affect the quality of sperm.
• environmental factors – exposure to certain pesticides, solvents and metals has been shown to affect fertility, particularly in men
• stress – can affect your relationship with your partner and cause a loss of sex drive; in severe cases, stress may also affect ovulation and sperm production

There’s no evidence to suggest caffeinated drinks, such as tea, coffee and colas, are associated with fertility problems.

Infertility can be caused by many different things. For 1 in 4 couples, a cause cannot be identified.

Infertility in women

Infertility is commonly caused by problems with ovulation (the monthly release of an egg from the ovaries).

Some problems stop an egg being released at all, while others prevent an egg being released during some cycles but not others.

Ovulation problems can be a result of:

• polycystic ovary syndrome (PCOS)
• thyroid problems – both an overactive thyroid gland and an underactive thyroid gland can prevent ovulation
• premature ovarian failure – where the ovaries stop working before the age of 40

Scarring from surgery

Pelvic surgery can damage and scar the fallopian tubes, which link the ovaries to the womb.

Cervical surgery can also sometimes cause scarring or shorten the neck of the womb (the cervix).

Cervical mucus problems

When you’re ovulating, mucus in your cervix becomes thinner so sperm can swim through it more easily. If there’s a problem with the mucus, it can make it harder to conceive.

Fibroids

Non-cancerous growths called fibroids in or around the womb can affect fertility. In some cases, they may prevent a fertilised egg attaching itself in the womb, or they may block a fallopian tube.

Endometriosis

Endometriosis is a condition where small pieces of the womb lining (the endometrium) start growing in other places, such as the ovaries.

This can damage the ovaries or fallopian tubes and cause fertility problems.

Pelvic inflammatory disease

Pelvic inflammatory disease (PID) is an infection of the upper female genital tract, which includes the womb, fallopian tubes and ovaries.

It’s often caused by a sexually transmitted infection (STI). PID can damage and scar the fallopian tubes, making it virtually impossible for an egg to travel down into the womb.

Sterilisation

Some women choose to be sterilised if they do not want to have any more children.

Sterilisation involves blocking the fallopian tubes to make it impossible for an egg to travel to the womb.

It’s rarely reversible – if you do have a sterilisation reversed, you will not necessarily be able to have a child.

Infertility in men

Semen and sperm

A common cause of infertility in men is poor-quality semen, the fluid containing sperm that’s ejaculated during sex.

Possible reasons for abnormal semen include:

• a lack of sperm – you may have a very low sperm count or no sperm at all
• sperm that are not moving properly – this will make it harder for sperm to swim to the egg
• abnormal sperm – sperm can sometimes be an abnormal shape, making it harder for them to move and fertilise an egg

Many cases of abnormal semen are unexplained.

Unexplained infertility

Unexplained infertility accounts for around 1 in 4 cases of infertility. This is when no cause can be identified in either partner.

If a cause for your fertility problems has not been found, talk to your doctor about the next steps.

Regular unprotected sex means having sex every 2 to 3 days without using contraception.

When to get medical help

See your Doctor if you have not conceived after a year of trying.

You should see a Doctor sooner if:

• you are female and are aged 36 or over – the decline in fertility speeds up when reaching your mid-30s
• have any other reason to be concerned about your fertility, for example, if you’ve had treatment for cancer or you think you might have had a sexually transmitted infection (STI)

Fertility tests can take time and female fertility decreases with age, so it’s best to make an appointment early.

The Doctor will be able to do an initial assessment to check for things that may be causing your fertility problems and advise you about what to do next.

It’s always best for both partners to visit the Doctor as fertility problems can affect either or both partners.

Trying to conceive can be an emotional process, so it’s important to support each other as much as possible. Stress is just one factor that can affect fertility.