Fertility problems are sometimes called infertility or subfertility. This is when a couple are not getting pregnant even though they are having regular sex with no contraception.

Fertility problems can affect men and women. They can affect heterosexual couples and same-sex couples.

Around 1 in 6 heterosexual couples in Ireland may experience infertility. But 85% of couples will conceive a child naturally after one year of trying. This figure rises to 95% after two years.

‘Trying' means having regular unprotected sex every 2 to 3 days.

If you are a man or a woman in a same-sex relationship, you may need some fertility treatments. What treatment is needed depends on the path to parenthood that you choose.

There are a number of things that can cause fertility problems. Some of these problems can be treated. In 20% of infertility cases, no cause is ever found.

See your GP if you are worried about your fertility. They will be able to offer advice, examine you and arrange tests.

The next steps taken by your GP depend on:

  • your own situation and any medical issues you may have
  • your age
  • how long you have been trying to get pregnant
  • any findings from a physical examination
  • results of blood tests
  • results of semen analysis

You may need to see a fertility specialist or a gynaecologist. They might recommend more tests or to begin treatment.

Generally speaking, there are two types of fertility problems:

Primary infertility

This is when a couple who has never been pregnant is experiencing infertility.

Secondary infertility

This is when a couple has had one or more previous pregnancies but is now struggling to conceive.

Risk factors for fertility problems (infertility)

There are certain things that can affect the fertility of both men and women.

These include:


Age can affect the fertility of women and men. It mainly affects women. For women, a decrease in fertility may occur around the mid-30s.


Having a body mass index (BMI) of 30 or over reduces fertility in men and women.

If a woman is underweight (BMI less than 18), it may affect ovulation (when an egg is released from one of the ovaries).

Sexually transmitted infections (STIs)

Some STIs, including chlamydia and gonorrhoea, can affect fertility.


Smoking can affect fertility in both men and women. This includes passive smoking (inhaling smoke from other people’s smoking).

For women, smoking may reduce your chance of conceiving.

For men, smoking could reduce the quality of semen.


For women planning to get pregnant, the safest approach is not to drink alcohol at all. This will minimise the risks to your baby.

For men, drinking too much alcohol can affect the quality of sperm. The recommendation for men is not to drink more than 17 standard drinks per week. One standard drink is equivalent to half a pint of beer or a small glass of wine. The drinks should be spread out over the course of a week with at least 2 alcohol-free days.

Information on how alcohol affects your health and support on the HSE's Ask About Alcohol website

Environmental factors

Exposure to certain pesticides, solvents and metals may 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.

Page last reviewed: 10 May 2019
Next review due: 10 May 2022