What can cause fertility problems?

Understand the reasons and explore your options.

If you want to know more about what can affect fertility in women, men and couples together, below you’ll find some of the most common conditions or causes of fertility issues.

What can affect fertility in women?

There are three common areas where things can be wrong and make it difficult getting pregnant, but this list is not exclusive and your own individual situation may not fit within one of these categories:

Problems with hormones

  • Anovulation

    Ovulation is controlled by your fertility hormones. So if for any reason your hormone levels are disturbed, your ovulation can be affected. A sign of possible ovulation problems is very irregular or no periods. You may find that you are ovulating, but not every cycle.

    Hormonal disturbance that can affect ovulation can be caused by many factors. These include dramatic changes in weight, stress, strenuous exercise and illness. If you fail to see PEAK on Clearblue Fertility Monitor or Clearblue Digital Ovulation Test with Dual Hormone Indicator, or don’t detect the LH surge with ovulation tests for 3 consecutive cycles it would be worth speaking to a healthcare professional.

  • Polycystic Ovarian Syndrome (PCOS)

    PCOS means a woman has multiple cysts on her ovaries and a hormone imbalance. Your doctor will be able to diagnose it with a blood test. Please visit your doctor for further advice. Symptoms can include weight gain, excess hair growth as well as problems trying to conceive.

  • Short Luteal Phase

    If the number of days between when you ovulate and when your next period starts is too few (less than 10), this can mean that although you may conceive, the fertilised egg is expelled before it can implant in the lining of the womb. This something you may notice if you are using an ovulation test or fertility monitor – count the number of days between your second peak fertile day and when your period starts. Talk to your doctor about this as the condition may be treatable.

  • Early Menopause

    Once you have reached menopause pregnancy is not possible, and in the lead up to menopause (the perimenopause) it can be very difficult to become pregnant. If your mother had an early menopause your chances are much higher, so, try to find out at what age your mother started menopause. If she had an early menopause it may be worth talking to a healthcare professional about your future plans for pregnancy.

Problems with Fallopian tubes

A blockage in your Fallopian tubes can prevent sperm getting to the egg.

Untreated chlamydia infection

The most common cause of blocked Fallopian tubes is a chlamydia infection that has been left untreated. Chlamydia is a common infection that is easily transmitted by unprotected sex. Some women may be completely unaware that they ever had a chlamydia infection due to the lack of symptoms. If there’s a chance you could have contracted Chlamydia, go to your doctor for a test.


These are abnormal growths of muscular tissue in the womb that can block the Fallopian tubes or stop a fertilised egg implanting. Please visit your doctor for further advice.


This is when the tissue that lines the womb grows outside the womb. It can obstruct the Fallopian tubes and can prevent fertilisation. Endometriosis can cause heavy and/or very painful periods. It can be treated by medication or by removing the extra tissue. Your doctor will be able to tell you more.

Other Considerations

Vaginal dryness is more common than we may think. In a study across 11 countries involving 6,725 women, up to 18% of women aged 18–34 years reported always or usually experiencing vaginal dryness. This can be exacerbated by the tendency for 'baby-making sex' when trying to conceive. Some of the most commonly available lubricants can be toxic to sperm and even saliva is – so be sure to use a sperm-friendly lubricant. Unprotected intercourse in the days leading up to and/or on the day of ovulation is needed to become pregnant. This can be achieved by sex every couple of days, but many couples find this undesirable. Therefore, making sure you know when you ovulate and having intercourse at this time will maximise your chances of a natural conception.

What can affect fertility in men?

These issues fall into three areas:

  • Low sperm count or poor sperm quality

    If there aren’t as many sperm as usual in the male ejaculate, the chances of a sperm fertilising an egg are reduced. If the sperm quality is poor they may be unable to reach the egg and break through the membrane to fertilise the egg. Sperm production can be lowered if the testes aren’t kept cool. Your partner can make sure his testicles don’t get too hot by wearing loose underwear. Sperm count and quality can be assessed by a simple test which you can get via your doctor.

  • Erectile dysfunction

    If the man has trouble getting or maintaining an erection, for physical or psychological reasons, he’ll find it difficult to have sex. There is help available, so see your doctor.

  • Other causes

    Much less common causes of male fertility problems include a blockage in the tube that carries sperm from the testicles, a genetic cause, hormone problems or other rarer conditions. Your doctor will be able to identify these problems through tests.

What can lower fertility?1


  • Drinking alcohol

    Fertility in both men and women can be affected by drinking too much alcohol. Clinical guidelines in the UK advise a maximum of 1-2 units per day for women and 3-4 units per day for men, whether you are trying to conceive or not. Reducing the amount of alcohol you drink can help you to conceive.

  • Smoking

    Compared to non-smokers, men who smoke can have a lower sperm count and/or a higher number of abnormal sperm. In women, smoking can affect fertility and trigger early menopause. It can also increase the risk of miscarriage and early onset of labour.Smoking is very bad for the health of your unborn baby and it is best to stop smoking before you become pregnant.

    Both you and your partner should try to stop smoking if you’re trying to conceive.

  • Recreational Drugs

    There are many different sorts of recreational/illegal drugs used today and how they affect fertility is not well studied.As many drugs can have bad effects on a developing baby, you should stop using any recreational/illegal drugs when trying to conceive.


Being underweight or overweight can alter your menstrual cycle and reduce your chances of conception. Overweight men can have a lower sperm count and poor sperm quality. Visit your doctor or nurse to know the ideal weight for you and for practical advice on gaining or losing weight if it’s necessary.


If you, or your partner, are taking any medication, check with your doctor that it won’t reduce your fertility. There may be alternatives available.


You are born with a lifetime’s supply of eggs and the number reduces gradually with age. After 38-40 years the rate of loss is much faster and the quality of the eggs also declines. If you’re over 35, it’s a good idea to visit your doctor after around six months of trying and if you’re over 40, ask your doctor for advice when you start trying to conceive. Less is known about fertility in older men but it’s thought to decline from around the age of 40 too.

Unexplained infertility

Sometimes all clinical tests will be reported as normal but after years of trying you’re not pregnant. This can be very frustrating and distressing because there is nothing to focus on that can be rectified or treated. It is estimated that around one third of couples with unexplained infertility will get pregnant naturally within three years without intervention2.

What is sub-fertility and infertility?

The majority of couples who have tried to conceive for over two years without success are technically ‘sub-fertile.’ Although ovulation and sperm production may occur they can have difficulty conceiving due to issues with hormones or physical difficulties in the reproductive tract. Many fertility problems can be treated, so if you’re worried, visit your doctor. Complete infertility – where the woman doesn’t ovulate at all or the man’s ejaculate doesn’t contain sperm - is rare – a study has suggested approximately 9% of the population3.

Fertility issues are in approximately one third of cases due to a female related problem, one third due to a male related problem and in one third of cases due to an issue of compatibility or a combined problem4.

If you have been trying for a baby for a year with no success and are under 35, we recommend that you speak to your healthcare professional for further advice. If you are aged over 35, you should seek help after 6 months trying, and immediately if you are over 40.

  • 1 Leiblum SR, et al. Vaginal dryness: a comparison of prevalence and interventions in 11 countries. J Sex Med. (2009) 6: 2425–2433.
  • 2 NICE Clinical Guidline 62 (2008)
  • 3 Boivin J., et al. International estimates of infertility prevalence and treatment-seeking: potential need and demand for infertility medical care Human Reproduction (2007) 22: 1506-12
  • 4 www.hfea.gov.uk

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