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Causes - Fertility problems

There are many possible causes of fertility problems in women and men.

You can get treatment for most causes of fertility problems.

Causes of infertility in women

Many things can cause fertility problems in women, including ovulation problems, endometriosis and pelvic infections.

Ovulation problems

If your ovaries don't release an egg each month, you may have ovulation problems. This can affect your fertility.

You may have an ovulation problem if you have:

Ovulation problems can be caused by:

Endometriosis

Endometriosis is a condition where tissue similar to the lining of the womb starts to grow in other places, such as your ovaries or the lining of your tummy.

This can damage the ovaries and cause adhesions (scarring) in the pelvis and around your fallopian tubes. This may cause fertility problems in some women. But not all women with endometriosis will have fertility problems.

Damaged or blocked fallopian tubes

Fallopian tubes are the two tubes connecting your ovaries to your womb.

Your fallopian tubes can become damaged, blocked or scarred by:

  • pelvic inflammatory disease (PID)
  • pelvic or abdominal (tummy) surgery
  • an ectopic pregnancy - you may need to have a tube removed

Surgery to repair your fallopian tubes may help you to become pregnant. But this surgery is not suitable for all women. You may be advised about IVF or other fertility treatments.

Scarring from cervical surgery

Major surgery to your cervix may cause scarring. This may affect your ability to get pregnant.

Minor surgery such as a large loop excision of the transformation zone (LLETZ) is not likely to cause fertility problems.

LLETZ

Cervical cancer surgery

Health conditions and treatments

Health conditions that may affect your fertility include:

Certain medicines and treatments may also affect your fertility.

These include:

  • contraception
  • cancer treatments such as radiotherapy and chemotherapy
  • anti-psychotic medicines
  • large doses of non-steroidal anti-inflammatory drugs (NSAIDs) such as ibuprofen or aspirin
  • some herbal and "alternative" medicines

Do not stop taking your prescribed medicine without talking to your GP first.

Speak to your GP if you are taking any medicines you bought without a prescription or herbal remedies.

Fibroids

Fibroids are benign (not harmful) tumours that grow in the muscle wall of your womb. Depending on their location, they may cause fertility problems in some women.

They may:

  • stop a fertilised egg from attaching to your womb
  • block a fallopian tube
  • stop sperm from reaching the egg - this is rare
Cervical mucus problems

When you're ovulating, mucus in the neck of your womb (the cervix) becomes thinner. This lets sperm swim through it more easily.

If there's a problem with your mucus, it can make it harder for the sperm to get into your womb.

Problems with sex

Problems with sex for women include:

  • vaginismus (not being able to have vaginal sex)
  • a loss of sex drive
  • pain during sex

If you or your partner have problems with sex, it can be difficult for your relationship. Talk about your problems with your GP as soon as possible.

Causes of infertility in men

The most common cause of fertility problems in men is problems with sperm.

Sperm may:

  • be low in number
  • not be in your semen at all
  • not be as good at swimming or moving as they should be
  • have an unusual shape that makes it harder for them to move or get inside the egg
Low sperm count or poor-quality sperm

There are many things that can cause problems with your sperm count or quality.

These include:

  • previous cancer treatment
  • smoking
  • alcohol
  • drug use, including performance enhancing steroids
  • current or past sexually transmitted infections (STIs), such as gonorrhoea and chlamydia
  • testicles that did not "drop" properly as a baby
  • issues with your testicles because of surgery, enlarged veins (varicocele) or tumours
  • medical conditions such as a thyroid problem or poorly-controlled diabetes
  • hormonal problem such as hypogonadism - where you make little or no testosterone
  • genetic problems such as Klinefelter syndrome
  • your testicles overheating
Problems with sex

Problems with sex for men include:

  • erectile dysfunction (impotence)
  • ejaculation problems such as retrograde ejaculation (when sperm moves into the bladder instead of outside the penis)
  • difficulty having an orgasm

If you or your partner have problems with sex, it can be difficult for your relationship. Talk about your problems with your GP as soon as possible.

Health conditions and treatments

Health conditions that may affect your fertility if you're a man include:

  • cancer
  • thyroid problem
  • poorly-controlled diabetes
  • cystic fibrosis
  • spina bifida
  • any chronic illness that impacts your health

Certain medicines and treatments may also affect your fertility.

These include:

  • cancer treatments such as radiotherapy and chemotherapy
  • performance enhancing steroids
  • testosterone medicines
  • some anti-depressants and anti-psychotic medicines
  • some epilepsy medicines
  • some blood pressure medicines
  • large doses of non-steroidal anti-inflammatory drugs (NSAIDs) such as ibuprofen or aspirin
  • some herbal and "alternative" medicines
  • some medicines used for treating auto-immune disorders

Do not stop taking your prescribed medicine without talking to your GP first.

Speak to your GP if you are taking any medicines you bought without a prescription or herbal remedies.

Lifestyle factors that can affect your fertility

Many things can affect your fertility if you're a man or a woman.

Age

Getting older affects your fertility. This strongly affects women. For women, your fertility starts to reduce from your 30s. As you get older, the number and quality of your eggs reduce.

For men, your fertility may start to reduce in your mid-40s. You may start to make less sperm and your sperm quality may not be as good.

Age and trying for a baby

Weight

Weight can affect your fertility. For women, being underweight or overweight may stop ovulation (production of eggs).

For men, having obesity can affect the number and quality of your sperm.

Healthy weight when trying to get pregnant

Obesity

Smoking

Smoking can strongly affect your fertility. This includes inhaling smoke from other people smoking (passive smoking).

Get help to quit smoking

Alcohol and drugs

For women, if you are planning to get pregnant, it is safest to not drink alcohol at all. This will reduce the risks to you and your baby such as miscarriage.

For men, drinking too much alcohol can affect the quality of your sperm.

Using drugs can also affect your fertility. For example, in men, regular cannabis use can affect the quality of your sperm and how much sperm you have.

How alcohol affects your sex life and fertility

Find out more about drugs and alcohol - drugs.ie

Environment

Being around some pesticides, solvents, metals and high air temperatures may affect fertility, particularly in men.

Unexplained infertility

Sometimes there’s no known cause of fertility problems (unexplained infertility).

You can still get fertility treatment if no cause is found for your fertility problems.

When to go to your GP about fertility problems

Page last reviewed: 13 September 2023
Next review due: 13 September 2026