Infertility is when a couple can't get pregnant (conceive), despite having regular unprotected sex.
Around one in seven couples may have difficulty conceiving. This is approximately 3.5 million people in the UK.
About 84% of couples will conceive naturally within one year if they have regular unprotected sex (every two or three days).
For couples who've been trying to conceive for more than three years without success, the likelihood of getting pregnant naturally within the next year is 25% or less.
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Some women get pregnant quickly, but for others it can take longer. It's a good idea to see your GP if you haven't conceived after one year of trying.
Women aged 36 and over, and anyone who's already aware they may have fertility problems, should see their GP sooner. Your GP can check for common causes of fertility problems and suggest treatments that could help.
Infertility is only usually diagnosed when a couple haven't managed to conceive after one year of trying.
There are two 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 one or more pregnancies in the past, but is having difficulty conceiving again
Read more about how infertility is diagnosed.
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 – this may be intrauterine insemination (IUI) or in-vitro fertilisation (IVF)
The treatment offered will depend on what's causing your fertility problems and what's available from your local clinical commissioning group (CCG).
Private treatment is also available, but it can be expensive and there's no guarantee it will be successful.
It's important to choose a private clinic carefully. You can ask your GP for advice, and should make sure you choose a clinic that's licensed by the Human Fertilisation and Embryology Authority (HFEA).
Read more about how infertility is treated.
Some treatments for infertility, such as IVF, can cause complications.
- multiple pregnancy – if more than one 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 the man or the woman. However, in a quarter of cases it isn't possible to identify the cause.
In women, common causes of infertility include:
- lack of regular ovulation, the monthly release of an egg
- blocked or damaged fallopian tubes
- endometriosis – where tissue that behaves like the lining of the womb (the endometrium) is found outside the womb
In men, the most common cause of infertility is poor-quality semen.
There are also a number of factors that can affect fertility in both men and women.
- age – female fertility and, to a lesser extent, male fertility decline with age; in women, the biggest decrease in fertility begins during the mid-30s
- weight – being overweight or obese (having a body mass index (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 in both sexes: smoking (including passive smoking) affects a woman's chance of conceiving, while in men there's an association between smoking and reduced semen quality; read more about quitting smoking
- alcohol – for women planning to get pregnant, the safest approach is not to drink alcohol at all to keep risks to your baby to a minimum; for men, drinking too much alcohol can affect the quality of sperm (the chief medical officers for the UK recommend men and women should drink no more than 14 units of alcohol a week, which should be spread evenly over three days or more)
- 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.
To find out more about what you can do to protect your fertility, see: