Facts and figures surrounding IVF

Fertility experts are celebrating IVF's 40th anniversary.

But what is in vitro fertilisation? Here are some questions answered.

What is IVF?

In vitro fertilisation (IVF) is probably the best-known technique for helping people with fertility problems have a baby.

During the process, an egg, or multiple eggs, are removed from a woman's ovary and fertilised with sperm in a laboratory.

The fertilised egg is then returned to the woman's womb to grow and develop.

Who uses it?

It is most commonly used with couples who are having fertility problems.

Others who can use the technique include same-sex couples or single women.

NHS Choices estimates that around one in seven couples in the UK have trouble conceiving - around 3.5 million people in Britain.

What causes infertility?

Fertility problems can affect either men or women. In one in four cases, it isn't possible to determine the cause.

In women, common causes of infertility include: ovulation problems, issues with fallopian tubes or a condition called endometriosis.

How successful is IVF?

IVF success rates depend on how old the woman undergoing treatment is.

According to NHS Choices, in 2010 the percentage of IVF treatments that resulted in a live birth was; 32.2% for women under 35, 27.7% for women aged 35 to 37, 20.8% for women aged 38 to 39, 13.6% for women aged 40 to 42, 5% for women aged 43 to 44.

Are there any risks?

There are risks associated with IVF which include side effects from the medication, ovarian hyperstimulation syndrome, multiple births and ectopic pregnancies. Treatments can also take their toll on mental wellbeing.

Can I get it on the NHS?

The National Institute for Health and Care Excellence recommends that eligible patients should have access to three rounds of IVF funded through the NHS.

But just 12% of local health bodies offer this many cycles - others offer one or two cycles and some offer none at all.

How much does it cost privately?

Costs vary but they can be around £5,000 for one cycle.

How many babies have been born using the technique?

Estimates suggest that around six million babies have been born around the world using the technique. Data from the Human Fertilisation and Embryology Authority (HFEA) show that between 1991 and 2015 more than 300,000 children have been born in the UK over the last quarter of a century thanks to IVF and donor insemination.

By the end of 2015, the number of cycles of in vitro fertilisation cycles carried out since 1991 stood at 1,034,601, according to the HFEA.