Most people just aren't comfortable mentioning the F-word in public - the fertility word, that is.

While around one in six UK couples have difficulty conceiving, the topic tends not to be discussed openly, which means it's often a hidden struggle.

This is something that will be addressed during the forthcoming National Fertility Awareness Week (October 27-November 2), which aims to get people talking about fertility, highlight the heartbreak infertility can cause, and outline the options for dealing with the problem.

Susan Seenan, chief executive of Infertility Network UK, which is spearheading the week, says that around 3.5 million people in the UK have trouble conceiving.

"That's a lot of people, and yet they're not talking about it," she adds. "We're asking, 'Are you talking about the F-word?', because we don't think people are, yet almost everybody will know somebody that's affected.

"We just want people to talk about infertility and understand that it's not something to be ashamed of. It's something you're suffering from, and there's help available."

Seenan says many people lie about their reasons for not having children, because they feel embarrassed and a failure if they're unable to conceive. And if there's a medical problem with one partner, they will often feel they've let the other partner down.

"People shouldn't blame themselves," she says. "You wouldn't be blaming yourself if you got pneumonia or another illness, but people feel their fertility is something they should be able to control and they can't, so they feel ashamed, and want to keep this very personal issue to themselves."

Infertility can have many causes, including blocked fallopian tubes or endometriosis in a woman, a low sperm count in a man, or 'unexplained infertility', when tests find no obvious physical problems in the couple.

"Because there's nothing apparently wrong, and nothing that can be treated, unexplained infertility can be even harder to deal with," says Seenan. "And sometimes the more people worry, and the more focused they are on trying to conceive, the harder it can be to get pregnant."

Various treatments are available, depending on the cause of infertility; for example, drugs may be taken to stimulate ovulation, or surgery may be needed to treat blocked fallopian tubes, endometriosis or male blockage problems. If these aren't suitable or don't work, many couples turn to IVF.

The number of IVF cycles performed each year has increased steadily since 1991, and the latest figures from 2011 show that around 47,000 women received treatment, with more than 60,000 rounds of IVF or ICSI being given; 4.3% more than 2010.

ICSI (intra-cytoplasmic sperm injection) is where a single sperm is injected directly into an egg to fertilise it. In IVF, fertilisation occurs in a dish.

In 2010, the overall live birth rate per IVF/ICSI cycle was 24.5%, which means that around three quarters of cycles don't result in a baby - although clearly the more cycles a couple have, the better their chances of success.

NICE guidelines recommend offering three full IVF treatment cycles to women aged under 40 who've failed to get pregnant after two years of trying - although, largely due to costs, not every area offers this.

"Of all the people referred for IVF, some will be successful and a lot won't, and many people aren't prepared for that," says Seenan. "You want people to be positive, but sometimes you have to be realistic as well. And there's a postcode lottery for treatment, which is very cruel."

Some couples feel they have no option but to pay for IVF privately. Costs vary, but can be anything from £5,000 per cycle upwards.

The process can be far more involved and draining - both physically and emotionally - than people realise, and can also put a strain on relationships.

Staying relaxed can help couples' cope with their fertility struggles, as well as possibly generally improve their chances of having a baby, but of course, it's not easy.

"It's very, very hard to do that," says Seenan, "and the more you think about it, the harder it is.

"The impact fertility problems have is massively misunderstood," she adds. "We want more support for people who are struggling to conceive, including better access to counselling. Sometimes people just need someone to talk to that understands."

:: For more information about National Fertility Awareness Week, visit nfaw.org.uk. For information and support about infertility, visit www.infertilitynetworkuk.com or call the INUK helpline on 0800 008 7464

CAN A HEALTHY LIFESTYLE BOOST FERTILITY?

Making lifestyle changes can often be a big part of a couple's efforts to get pregnant. Midwife and fertility expert Zita West, author of new book Eat Yourself Pregnant (Nourish Books, £14.99), says much more is now understood about how food and nutrients affect hormones and fertility for both men and women.

"A diet has to comprise food that's nutritious and enjoyable, and most importantly, it has to be do-able, so you feel happy and relaxed, putting good things back into your system, not taking them out," says West.

Men and women frequently have different approaches towards diet and lifestyle, she notes, but one thing they often have in common is a tendency to see fertility as a series of separate problems and fixes, rather than understanding the role that nutrition plays in every part of it. "When you're trying to conceive, perhaps the saying 'you are what you eat' should read 'you both are what you eat'," she says.

Eggs and sperm are cells like any others, she notes, yet how they're nourished is largely ignored. The maturing egg, sperm, endometrium (womb lining) and foetus depend on nutrients for development, but if the diet contains too many environmental endocrine-disrupting chemicals - like trans-fats, refined sugars, or excess additives - or is depleted of nutrients, research shows fertility can be significantly affected.

Another dietary problem that can "play havoc" with fertility and hormones is blood-sugar imbalance. Eating slow-release carbohydrates can help, West advises.

Eating 'on the run', without time to properly chew and digest food, or eating late into the evening can also leave many women with digestive problems which might not help. "It's a feature of couples' hectic modern lifestyles, in which there are often other sources of stress too, and stress robs the body of essential nutrients needed for hormone production," West adds.

She says wholesome, traditional foods provide a good balance of the nutrients couples need to optimise fertility, but stresses there are too many modern food fads that exclude some of these key nutritional building blocks, including low-fat foods and highly processed foods containing trans-fats, known to have detrimental effects.

Being underweight or overweight can also cause fertility problems.

"Diet and lifestyle changes can help with hormone balance and energy levels, preparing you to be in the best possible shape to cope with pregnancy," says West. "Sperm also takes three months to develop, and being aware of what affects their quality can really make a difference."

Exposure to pollutants and toxins, recreational drugs and certain medications, lifestyle factors and stress can all play a part in affecting sperm count, motility and morphology (shape), explains West.

Mental and emotional factors also play a major role. West stresses that the uncertainty of not knowing when, or if, a woman will get pregnant can have a detrimental effect on their chances.

"It's important that we help manage expectations, knowing that it can take up to a year to conceive," she says. "A woman will also often put great pressure on herself and her partner around ovulation, which creates stress that depletes the body of nutrients needed for optimum fertility."

ZITA WEST'S TOP DIET TIPS:

According to West, a diet designed for optimum fertility needs to include:

:: Protein to build hormones, eggs and sperm - from meat, fish, chicken, and plant proteins.

:: Essential fatty acids for hormone production and a healthy immune system and cell membranes - from oily fish, nuts and seeds.

:: Slow-release carbohydrates for energy - from any brown cereals.

:: B vitamins and folic acid for cell division - from green vegetables.