Causes of Infertility

Infertility is described as the inability to achieve a successful pregnancy within 12 months of regular and unprotected intercourse. There are numerous causes of infertility, many of which can be overcome through fertility treatment or lifestyle changes.1 Read on to learn about the prevalence of infertility, its causes, how it is tested for and ways to increase your chances of getting pregnant.

How common is infertility?

If you and your partner have been struggling to conceive, it can feel overwhelming and isolating, but you’re not alone. Infertility is more common than you may think. In the UK, it is estimated that 1 in 6 couples are affected by infertility,1 and globally almost 50 million couples are unable to conceive naturally.2

Additionally, it is important to note the prevalence of pregnancy loss. Miscarriages are thought to occur in 10-25% of pregnancies, although this may in fact be higher, as many women may not be aware of their miscarriage, especially if it occurs early in the pregnancy.3

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Causes of infertility

Infertility can occur in any individual or couple of reproductive age. The main causes of infertility in the UK are1,4:

Dr. Sara Matthews Consultant Reproductive Medicine Discusses the Causes and Treatments of Infertility

Interview with Dr. Sara Matthews, Consultant Gynaecologist & Subspecialist in Reproductive Medice & Surgery discussing the causes of infertility and the treatments:

The effect of maternal age on the average rate of pregnancy

Annual Fertility Rate (per 1000 married women not using contraception)*

No Data Found

No Data Found

*Calculated on the basis of studies in 10 different populations that did not use contraceptives.5 Adapted from: Heffner LJ., N Engl J Med 2004.5

Additional causes of infertility in both men6-9 and women7,10-12 include:



Diagnostic testing for infertility

If you and your partner are concerned about your ability to get pregnant, it may be a good idea for you both to speak to your doctor. To help determine any underlying cause, your doctor will ask you a number of questions about your medical and sexual history, which may include:13

It may be useful to have a think about these questions before your visit, so that you can answer accurately and honestly, and get the most out of your appointment.

Your doctor may run the following diagnostic tests to help identify any possible fertility problems.

Fertility tests for women:

This will be one of the first tests you have in your fertility investigations. Your doctor may weigh you to work out your body mass index (BMI) and undertake a pelvic examination to check for any signs of infection, lumps, or tenderness.13
A blood sample may be taken to check that you are ovulating normally, which will indicate whether you are ovulating normally. If you have irregular periods, you may also be tested for gonadotrophins13 (hormones which stimulate your ovaries to release eggs) such as follicle-stimulating hormone (FSH) and luteinising hormone (LH),14 thyroid hormones,5 and anti-Müllerian hormone (AMH).1 Human immunodeficiency virus (HIV), hepatitis B and hepatitis C testing for viral status is also performed.1,13

You may be tested for chlamydia, either via a swab test or a urine sample. Chlamydia is a Sexually Transmitted Infection (STI) which can affect your fertility.13

An ultrasound scan can provide valuable information about the health of your ovaries, uterus, and fallopian tubes, which may be contributing to your fertility problems. If the ultrasound scan indicates a possible blockage in your fallopian tubes, you may then be referred for a laparoscopy.13

Otherwise known as keyhole surgery. This examination is done to gather more information about your ovaries, uterus, and fallopian tubes, after indication of a blockage from an ultrasound scan.13
An x-ray is an alternative method to a laparoscopy that determines if there is a blockage in your fallopian tubes.13

Fertility test for men:

A semen sample will be analysed in a laboratory to check for any problems with sperm, such as a low sperm count, poor motility (sperm that are moving too slowly or not at all), or poor morphology (abnormally shaped sperm).

A urine sample may be taken to test for chlamydia.

How to increase your chances of getting pregnant

1. Know your cycle

Getting to know the frequency and regularity of your menstrual cycle can provide valuable information about when you are most fertile. If you have regular monthly menstrual cycles it is highly likely that you are ovulating. You can learn more about your fertility cycle on our Understanding Fertility page.

Try: consistently tracking your cycle using a period tracker app, such as an ovulation calculator, or using ovulation predictor kits to determine when you are ovulating.

2. Maintain a healthy weight

Research has been shown that individuals with a BMI (Body Mass Index) that falls into the underweight or overweight range have an increased chance of infertility.14,15 You can use the calculator on the NHS webpage to check your BMI and find out if you are a healthy weight.

Try: eating a healthy, balanced diet and trying various exercises such as walking, cycling, or swimming

3. Take a pre-conception supplement16

Although eating a varied, healthy diet will give you most of the vitamins and minerals you need, pre-conception supplements can help support the nutritional requirements for someone trying to conceive.

4. Avoid smoking, alcohol, drugs, and caffeine

Smoking (including passive smoking) affects your chance of conceiving and can reduce semen quality.17 Excess consumption of alcohol18 and caffeine19 is associated with reduced fertility in both men and women. Illegal drugs, such as marijuana and cocaine, can seriously affect fertility, make ovulation more difficult and lower semen quality.20

Try: quitting smoking, swapping caffeinated drinks for decaf coffee or tea, or swapping alcoholic beverages for low-alcohol or alcohol-free drinks. The safest approach is to not drink alcohol at all and to not use any drugs to keep risks to your baby to a minimum

5. Lower your stress level

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.
You can find more ways to manage your stress level in our well-being section.

6. Know when to ask for help

If you have been trying to conceive for a while, it may be a good idea to seek help from your healthcare professional who can help identify any health issues that may be affecting your ability to get pregnant.

Try: speaking to your doctor if you are under 35 and have been trying to conceive for over 12 months, or if you are 35 or older and have been trying to conceive for over 6 months

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