If you're having problems getting pregnant, see your GP. They will look at your medical history and give you a physical examination.
They may also recommend some lifestyle changes to help increase your chances of getting pregnant (see planning your pregnancy).
Unless there are reasons that may put you at high risk of infertility, such as cancer treatment, you'll usually only be considered for infertility investigations and treatment if you've been trying for a baby for at least a year without becoming pregnant.
If appropriate, your GP can refer you to a fertility specialist at an NHS hospital or fertility clinic.
The specialist will ask about your fertility history, and may carry out a physical examination.
Women may have tests to check the levels of hormones in their blood and how well their ovaries are working.
Men may be asked for a semen sample to test sperm quality.
If IVF is the best treatment for you, the specialist will refer you to an assisted conception unit.
Read more about diagnosing infertility.
Your cervical screening tests should also be up-to-date.
The clinic should also check that you've been offered screening for sickle cell and thalassaemia if your ancestors come from a country where these conditions are more common. Anyone can ask to have this test for free on the NHS from their GP.
If you're planning to use donor eggs, check that these have been screened. All IVF clinics in the UK are required to screen donor eggs and sperm.
The specialist will investigate the number of eggs in your body (your ovarian reserve) to estimate how your ovaries will respond to IVF treatment.
This can be assessed by measuring a substance called anti-mullerian hormone (AMH) in your blood, or by counting the number of egg-containing follicles, known as your antral follicle count (AFC), using a vaginal ultrasound scan.
Your specialist will then discuss your treatment plan with you in detail and talk to you about any support or guidance you may find helpful.