Infertility is when a couple cannot conceive (get pregnant) despite having regular unprotected sex.
About 85% of couples will conceive naturally within one year if they have regular unprotected sex. However, the chances of becoming pregnant are much lower in older women.
For every 100 couples trying to conceive naturally:
- 20 will conceive within one month
- 70 will conceive within six months
- 85 will conceive within one year
- 90 will conceive within 18 months
- 95 will conceive within two years
For couples who have been trying to conceive for more than three years without success, the likelihood of pregnancy occurring within the next year is 25% or less.
Deciding to seek help
Some women get pregnant quickly but for others it can take longer. It is a good idea for a couple to visit their doctor if they have not conceived after one year of trying.
Women over the age of 36, and anyone who is already aware they may have fertility problems, should see their doctor sooner. The doctor can check for common causes of fertility problems, and suggest treatments that could help.
A couple will only be diagnosed as being infertile if they have not managed to have a baby after one year of trying. There are two types of infertility:
- primary infertility, where someone who has never conceived a child in the past has difficulty conceiving
- secondary infertility, where a person has had one or more pregnancies in the past, but is having difficulty conceiving again
Read more information about how infertility is diagnosed.
What causes infertility?
There are many potential causes of infertility, and fertility problems can affect either the man or the woman. However, it is not always possible to identify the cause.
Common causes of infertility in women include lack of regular ovulation (the monthly release of an egg), blockage of the fallopian tubes and endometriosis, although in 25-30% of cases the cause is unexplained. In men, the most common cause is poor quality of semen (the fluid containing sperm that is ejaculated during sex).
For some people, leading a healthy lifestyle and staying up to date with regular health checks and tests may help to prevent infertility.
What treatment is available?
Types of fertility treatment available include:
- medical treatment for lack of regular ovulation
- surgical procedures, such as treatment for endometriosis
- assisted conception, which may be intrauterine insemination (IUI)or in-vitro fertilisation (IVF)
You may wish to consider private treatment. This can be expensive and there is no guarantee it will be successful.
It is important to choose a private clinic carefully. You can ask your doctor for advice.
Read more information about how infertility is treated.
Some types of infertility treatment can cause complications including:
- side effects of medication
- increased risk of ectopic pregnancy
- multiple pregnancy
Read more information about complications associated with infertility treatments.
Infertility can be caused by many different things. In 25-30% of cases, a cause cannot be identified.
Infertility in women
Infertility is most commonly caused by problems with ovulation (the monthly release of an egg). Some problems stop women releasing eggs at all, and some cause an egg to be released during some cycles, but not others.
Ovulation problems can occur as a result of a number of conditions, listed below.
- Polycystic ovary syndrome (PCOS), a condition that makes it more difficult for your ovaries to produce an egg.
- Thyroid problems, both an overactive thyroid gland (hyperthyroidism) and an underactive thyroid gland (hypothyroidism) can prevent ovulation.
- Premature ovarian failure, where a woman’s ovaries stop working before she is 40.
Womb and fallopian tubes
The fallopian tubes are the tubes along which an egg travels from the ovary to the womb. The egg is fertilised as it travels down the fallopian tubes. When it reaches the womb, it is implanted into the womb's lining where it continues to grow.
If the womb or the fallopian tubes are damaged, or stop working, it may be difficult to conceive naturally. This can occur following a number of factors, outlined below.
Scarring from surgery
Pelvic surgery can sometimes cause damage and scarring to the fallopian tubes.
Cervical surgery can also sometimes cause scarring, or shorten the cervix (the neck of the womb).
Cervical mucus defect
When you are ovulating, mucus in your cervix becomes thinner so that sperm can swim through it more easily. If there is a problem with your mucus, it can make it harder to conceive.
Fibroids are benign (non-cancerous) tumours that grow in, or around, the womb. Submucosal fibroids develop in the muscle beneath the inner lining of the womb wall and grow into the middle of the womb.
Submucosal fibroids can reduce fertility, although exactly how they do this is not yet known. It is possible that a fibroid may prevent an embryo from implanting itself into your womb.
Endometriosis is a condition where small pieces of the womb lining, known as the endometrium, start growing in other places, such as the ovaries.
This can cause infertility because the new growths form adhesions (sticky areas of tissue) or cysts (fluid-filled sacs) that can block or distort the pelvis. These make it difficult for an egg to be released and become implanted into the womb.
Endometriosis can cause infertility because it can disturb the way that a follicle (fluid-filled space in which an egg develops) matures and releases an egg.
Pelvic inflammatory disease
Pelvic inflammatory disease (PID) is an infection of the upper female genital tract, which includes the womb, fallopian tubes and ovaries. It is often the result of a sexually transmitted infection (STI). PID can damage and scar the fallopian tubes, making it virtually impossible for an egg to travel down into the womb.
Some women choose to be sterilised if they do not wish to have any more children.
Sterilisation involves blocking the fallopian tubes to make it impossible for an egg to travel to the womb. This process is rarely reversible, and if you do have a sterilisation reversed, it will not necessarily mean that you will become fertile again.
Medicines and drugs
The side effects of some types of medication and drugs can affect your fertility. These medicines are outlined below.
- Non-steroidal anti-inflammatory drugs (NSAIDs). Long-term use, or a high dosage, of NSAIDs, such as ibuprofen or aspirin, can make it more difficult for you to conceive.
- Chemotherapy – Medicines used for chemotherapy (a treatment for cancer) can sometimes cause ovarian failure, which means your ovaries will no longer be able to function properly. Ovarian failure can be permanent.
- Neuroleptic medicines are antipsychotic medicines often used to treat psychosis. They can sometimes cause missed periods or infertility.
Illegal drugs such as marijuana and cocaine can seriously affect fertility, making ovulation (the monthly cycle where an egg is released from the ovaries) more difficult.
Infertility in women is also linked to age. The biggest decrease in fertility begins during the mid thirties. Among women who are 35, 95% will get pregnant after three years of having regular unprotected sex. For women who are 38, only 75% will get pregnant after three years of having regular unprotected sex.
Infertility in men
Male infertility is caused by abnormal semen (the fluid containing sperm that is ejaculated during sex). Some possible reasons for abnormal semen are listed below.
- Decreased number of sperm – You may have a very low sperm count, or no sperm at all.
- Decreased sperm mobility – If you have decreased sperm mobility, it will be harder for your sperm to swim to the egg.
- Abnormal sperm – Sometimes sperm can be an abnormal shape, making it harder for them to move and fertilise an egg.
- Many cases of abnormal semen are unexplained, but there are several factors that can affect semen and sperm.
The testicles are responsible for producing and storing sperm. If they are damaged it can seriously affect the quality of your semen. This may occur if you have, or have had in the past, any of the following:
- an infection of your testicles
- testicular cancer
- testicular surgery
- a congenital defect (a problem with your testicles that you were born with)
- undescended testicles (when one or both of your testicles has not descended into the scrotum)
- trauma (injury) to your testicles
Absence of sperm
Your testicles may produce sperm, but it may not reach your semen. The absence of sperm in your semen is known as obstructive azoospermia. This could be due to a blockage in one of the tiny tubes that make up your reproductive system, which may have been caused by an infection or surgery.
A vasectomy is the surgical procedure for male sterilisation. It involves cutting and sealing off the vas deferens (the tubes that carry sperm out of your testicles), so that your semen will no longer contain any sperm. A vasectomy can be reversed, but reversals are not usually successful.
Some men experience ejaculation problems that can make it difficult for them to ejaculate. Other ejaculation problems include:
- retrograde ejaculation, where semen is ejaculated into your bladder
- premature ejaculation, where ejaculation occurs too quickly
Hypogonadism is an abnormally low level of testosterone, the male sex hormone that is involved in making sperm. This could be due to a tumour, taking illegal drugs or Kallman’s syndrome (a rare disorder caused by a faulty gene).
Medicines and drugs
Certain types of medicines can sometimes cause infertility problems. These medicines are listed below.
- Sulfasalazine, an anti-inflammatory medicine used to treat conditions such as Crohn's disease (inflammation of the intestine) and rheumatoid arthritis (painful swelling of the joints). Sulfasalazine can decrease the number of sperm, but its effects are temporary and your sperm count should return to normal when you stop taking it.
- Anabolic steroids, often used illegally to build muscle and improve athletic performance. Long-term use or abuse of anabolic steroids can reduce sperm count and sperm mobility.
- Chemotherapy – Medicines used in chemotherapy can sometimes severely reduce sperm production.
- Herbal remedies – Some herbal remedies, such as root extracts of Tripterygium wilfordii (a Chinese herb), can affect the production of sperm or reduce the size of your testicles.
Drinking too much alcohol can damage the quality of your sperm.
Infertility in both men and women
There are a number of factors that can affect fertility in both men and women. These are outlined below.
Being overweight, or obese, reduces both male and female fertility. In women, being overweight can affect ovulation. Being underweight can also have an impact on fertility, particularly for women, who will not ovulate if they are severely underweight.
Sexually transmitted infections (STIs)
There are several STIs that can cause infertility. For example, chlamydia can damage the fallopian tubes in women, and cause swelling and tenderness of the scrotum (the pouch containing the testes) in men.
As well as affecting your general and long-term health, smoking can also adversely affect fertility. Read more information about [quitting smoking].
Occupational and environmental factors
Exposure to certain pesticides, metals, and solvents can affect fertility in both men and women.
If either you or your partner are stressed it may affect your relationship. Stress can contribute to a loss of libido (sex drive), which in turn can reduce the frequency of sexual intercourse. Severe stress may also affect female ovulation and limit sperm production.
Around 85% of couples conceive naturally within one year of having regular (every two to three days) unprotected sexual intercourse. You should visit your doctor if you have not conceived after one year of trying.
You should visit your doctor sooner if:
- you have any reason to be concerned about your fertility, for example, if you have had treatment for cancer
- you are a woman over the age of 35
Fertility testing and investigation can be a lengthy process, and female fertility decreases with age, so it is best to make an appointment early on.
Your doctor will be able to advise about what to do next, and carry out an initial assessment to investigate things that may be causing your fertility problems.
It is always best for both partners to visit their doctor because fertility problems can affect a man or a woman and sometimes both partners.
The process of trying to conceive can be an emotional one, so it is important to support each other as much as possible. Stress is just one of the things that can affect fertility.
Medical, sexual and social history
When you visit your doctor, they will want to discuss your full medical, sexual and social history. This will help them identify what may be causing fertility problems.
Your doctor will discuss your age, as fertility in women declines with age.
If you are a woman, your doctor will want to discuss with you any previous births and any related complications with your pregnancy. They will also ask about any miscarriages you may have had.
If you are a man, you will be asked whether you have had any children from previous relationships.
Length of time trying to conceive
Your doctor will ask how long you have been trying to conceive. Around 95% of couples are able to conceive naturally after two years of having unprotected sex. If you are young and healthy, and you have not been trying for a baby for very long, you may be advised to keep trying for a little longer.
You will be asked how often you have sex, and whether you have any difficulties during sex. You may feel uncomfortable or embarrassed about discussing your sex life with your doctor. However, it is very important to be open and honest. If the fertility problem is to do with sex, it might be overcome easily.
Length of time since stopping contraception
You will be asked about the type of contraception you previously used, and when you stopped using it. It can sometimes take a while for certain types of contraception to stop working, and this may be affecting your fertility.
Medical history and symptoms
Your doctor will want to discuss any medical conditions you have, or have had in the past, including sexually transmitted infections (STIs). If you are a woman, your doctor may ask how regular your periods are and whether you experience any bleeding between periods or after sex.
The side effects of some medication can affect your fertility. So your doctor will look at any medication you are taking, and might discuss alternative treatments with you. You should mention any non-prescription medication you are taking, including herbal medicines.
Several lifestyle factors can affect your fertility. Your doctor will want to know:
- if you smoke
- how much you weigh
- how much alcohol you drink
- whether you take any illegal drugs
- if you are stressed
They may recommend changes to your lifestyle to increase your chances of conceiving. Read more about preventing infertility.
After taking a medical, sexual and social history, your doctor may carry out a physical examination, or refer you for tests.
During a physical examination your doctor may:
- weigh you, to see whether you have a healthy body mass index (BMI)
- examine your pelvic area, to check for infection, lumps or tenderness, which could be an indication of fibroids](/condition/fibroids), ovarian tumours, endometriosis, or [pelvic inflammatory disease (PID) (see causes of infertility)
After your medical history and physical examination have been considered, you may be referred to a specialist infertility team at a fertility clinic for further tests and procedures. These are outlined below.
Tests for women
For women a number of tests can be used to try to establish the cause of infertility.
During a progesterone test, a sample of your blood can be tested for progesterone to check whether you are ovulating. The test is taken seven days before you expect your period to start.
If your periods are irregular, the level of follicle-stimulating hormone (FSH) and luteinising hormone in your blood may be tested along with thyroid hormone, prolactin and testosterone.
Chlamydia is an STI that can affect fertility. A swab (similar to a cotton bud, but smaller, soft and rounded) is used to collect some cells from your cervix to test for chlamydia. If you have chlamydia, you will be prescribed antibiotics to treat it.
Thyroid function test
It is estimated that between 1.3% and 5.1% of infertile women have an abnormal thyroid gland. If you have any symptoms of a thyroid abnormality, such as weight loss or weight gain, your thyroid gland will be tested to check whether it is functioning properly.
A hysterosalpingogram is a type of X-ray taken of your womb (uterus) and fallopian tubes after a special dye has been injected. This will outline the cavity of your womb and detect any blockage of the fallopian tubes.
A hysterosalpingo-contrast-ultrasonography is a type of ultrasound scan. A small amount of fluid will be injected into your womb through a tube that is put into your cervix (the womb opening). Ultrasound is used to confirm whether this fluid spills through the tubes.
A laparoscopy involves making a small incision (cut) in your lower abdomen. A thin, tubular telescope called a laparoscope will be used to look more closely at your womb, fallopian tubes and ovaries. Dye may be injected into your fallopian tubes through your cervix in order to highlight any blockages in them.
A laparoscopy is usually only used if there is a strong chance that you have a problem, for example, if you have had an episode of PID in the past.
Examination and tests for men
During a physical examination, your doctor may check:
- your testicles – to look for any lumps or deformities
- your penis – to look at its shape and structure, and for any obvious abnormalities
Further testing may include:
- a semen analysis – your semen will be tested to determine whether you have a low sperm count, low sperm mobility, or abnormal sperm
- a chlamydia test – a sample of your urine will be tested to determine whether you have chlamydia
If you do have chlamydia, your doctor will prescribe antibiotics to treat it.
If you have an infertility problem, you may wish to consider private treatment. This can be expensive and there is no guarantee of success.
It is important to choose a private clinic carefully.
You should find out:
- which clinics are available
- which treatments are offered
- the success rates of treatments
- the length of the waiting list
- the costs
Ask for a personalised, fully costed treatment plan that explains exactly what is included, such as fees, scans and any necessary medication.
If you decide to go private, you can ask your doctor for advice.
There are three main types of fertility treatment:
- medicines to assist fertility
- surgical procedures
- assisted conception
Medicines to assist fertility
Medicines often used to assist fertility are listed below. These are usually prescribed for women although, in some cases, they may also be prescribed for men.
- [Clomifene] helps to encourage ovulation (the monthly release of an egg) in women who do not ovulate regularly or who cannot ovulate at all.
- [Tamoxifen] is an alternative to clomifene that may be offered to women with ovulation problems.
- Metformin is particularly beneficial for women with polycystic ovary syndrome (PCOS).
- Gonadotrophins are medicines containing gonadotrophins that can help to stimulate ovulation in women, and may also improve fertility in men.
- Gonadotrophin-releasing hormone and dopamine agonists. These are other types of medication prescribed to encourage ovulation in women.
However, medication that stimulates the ovaries should not be given to women with unexplained infertility as it is not thought to be an effective treatment in these circumstances.
Surgical procedures that may be used to investigate fertility problems and assist with fertility are listed below.
Fallopian tube surgery
If your fallopian tubes have become blocked or scarred, perhaps as a result of pelvic inflammatory disease (PID), you may need surgery to repair the tubes. Surgery can be used to break up the scar tissue in your fallopian tubes, making it easier for eggs to pass along them.
The success of the surgery will depend on how damaged your fallopian tubes are. One study found 69% of women with the least damaged tubes had a live birth after surgery. Other estimates for live births in women following surgery are 20–50%.
Possible complications from tubal surgery include an ectopic pregnancy (when the fertilised egg implants outside of your womb). Between 8–23% of women may experience an ectopic pregnancy after having surgery on their fallopian tubes.
Laparoscopic surgery is often used for women who have endometriosis (when parts of the womb lining start growing outside of the womb), to destroy, or remove cysts (fluid-filled sacs). It may also be used to remove submucosal fibroids (small growths in the womb).
In women with PCOS, laparoscopic ovarian drilling can be used if ovulation medication has not worked. This involves using either heat or a laser to destroy part of the ovary.
Read more information about a laparoscopy.
Correction of an epididymal blockage and surgical extraction of sperm
The epididymis is a coil-like structure in the testicles that helps to store and transport sperm. Sometimes the epididymis becomes blocked, preventing sperm from being ejaculated normally. If this is causing infertility, surgery to correct the blockage can be performed.
Surgical extraction of sperm may be an option for men with:
- an obstruction which prevents the release of sperm, such as an injury or infection
- a congenital absence of the vas deferens (men born without the tube that drains the sperm from the testicle)
- a vasectomy biopsy of the testicular tissue after making a small incision in the scrotal skin
Both procedures only take a few hours and are carried out as outpatient procedures under local anaesthetic. You will be advised on the same day about the quality of the material collected and whether there are any sperm present.
Any material with sperm will be frozen and placed in storage for use at a later stage. If surgical retrieval of sperm is successful, usually enough sperm is obtained for several cycles of treatment (if required).
Intrauterine insemination (IUI)
Intrauterine insemination (IUI) involves sperm being placed into the womb through a fine plastic tube. Sperm is collected and washed in a fluid. The best quality specimens (the fastest moving) are selected.
The sperm are passed through a tube that enters the cervix and extends into the womb. This procedure is performed to coincide with ovulation in order to increase the chance of conception. The woman may also be given a low dose of ovary stimulating hormones to increase the likelihood of conception.
Some women may experience temporary cramps similar to period cramps after, or during IUI, but other than that the procedure should be painless.
Availability and success
IUI tends to be used when:
- Infertility cannot be explained.
- The man has a low sperm count, or decreased sperm mobility.
- The man is impotent (erectile dysfunction, an inability to maintain an erection), or premature ejaculation (when you ejaculate too quickly).
- The woman has mild endometriosis (where small pieces of the womb lining grow in other places).
Provided that the man's sperm and the woman's tubes are healthy, the success rate for IUI in women under 35 is around 15% for each cycle of treatment.
In-vitro fertilisation (IVF)
During in-vitro fertilisation (IVF) the fertilisation of the egg occurs outside the body. The woman takes fertility medication to encourage her ovaries to produce more eggs than normal. Eggs are then removed from her ovaries and fertilised with sperm in a laboratory dish. A fertilised embryo is then put back inside the woman's body.
There are several different methods that can be used during IVF and intracytoplasmic sperm injection (ICSI).
The success rate for a cycle of IVF is about 32% for women under 35 years of age. The success rate decreases as the woman’s age increases.
Egg and sperm donation
If you or your partner has an infertility problem, you may be able to receive eggs or sperm from a donor to help you conceive. Treatment with donor eggs is usually carried out using IVF.
For some, adopting a healthier lifestyle through simple lifestyle changes, or staying up to date with regular health checks and tests, may help to prevent infertility.
Women who are underweight or overweight ovulate (release an egg) less regularly, or sometimes not at all, compared to women of a healthy weight.
Therefore ensuring you maintain a healthy weight will make it easier to conceive. Use the healthy weight calculator to find out if you are the right weight for your height.
Women should aim for a body mass index (BMI) of 19–25 for the best chance of getting pregnant. A BMI of less than 19 may mean you are ovulating less frequently. If your BMI is over 29, your doctor may recommend that you lose weight.
Men with a BMI over 29 may have reduced fertility, and your doctor may recommend that you lose weight. Regular exercise and a healthy diet can help maintain a suitable weight.
Make sure that you eat a nutritious, balanced diet of at least five portions of fruit and vegetables a day. Include carbohydrates such as wholemeal bread and pasta, and lean meat, fish, and pulses for protein. Green, leafy vegetables are high in folic acid, which can help prevent birth defects.
Stress can often affect fertility because it may lead to you having sex less frequently. For the best chance of becoming pregnant, you need to have sex every two to three days. Talk to your partner if you are feeling stressed and consider using counselling (talking therapy). You may also find regular exercise helpful.
Medicines and drugs
Illegal drugs such as marijuana or cocaine can affect fertility, and can seriously damage the development of your baby if you fall pregnant. You should therefore avoid using them.
You should also avoid using some prescription medicines if you are trying to get pregnant. Ask your doctor for further advice.
Health checks and tests for women
Make sure you are up-to-date with your cervical screening tests (smear tests). You need to have one every three to five years, depending on your age.
You should also visit your local sexual health clinic (GUM clinic) to make sure you do not have any sexually transmitted infections. Infections such as chlamydia may not have symptoms but can cause infertility if left untreated.
Some fertility treatments can cause complications, including side effects from medication, multiple pregnancy and stress.
Side effects of medication
Some medications used to treat infertility can cause side effects. These may include:
For a full list of possible side effects, please see the patient information leaflet that comes with your medication, or read our [medicines information] page.
Ovarian hyperstimulation syndrome
Ovarian hyperstimulation syndrome (OHSS) can occur after taking medicines that stimulate your ovaries, such as clomifene and gonadtrophins, and can develop after a round of in-vitro fertilisation (IVF). OHSS causes your ovaries to swell and produce too many follicles (small fluid-filled sacs in which an egg develops).
Around one-third of women will experience mild OHSS after one cycle of IVF. Less than 10% will develop moderate or severe OHSS after one cycle of IVF.
Mild symptoms may include:
- abdominal pain
- constipation (when you are unable to empty your bowels)
- dark, concentrated urine
Severe OHSS is a potentially life-threatening condition and can lead to:
- thrombosis (a blood clot in an artery or vein)
- liver and kidney dysfunction
- respiratory distress (difficulty breathing)
You should seek medical attention immediately if you experience any of the symptoms of OSHH.
You may need to go to hospital so your condition can be monitored and treated by healthcare professionals.
"Ectopic" means in the wrong place. An ectopic pregnancy occurs when the fertilised egg implants outside your womb. More than 95% of ectopic pregnancies occur in the fallopian tubes.
If a fertilised egg implants itself in your fallopian tube and continues to grow, it can result in a miscarriage, and there is a risk of the tube bursting. Signs of an ectopic pregnancy include:
- pains low down in your stomach
- vaginal bleeding
Speak to your doctor if you experience either of these symptoms early in your pregnancy.
If you are receiving fertility treatment, your chance of having an ectopic pregnancy is around 4%. This is higher than the usual rate of ectopic pregnancies, which is around 1%. You may be more likely to have an ectopic pregnancy if you have already had problems with your fallopian tubes.
The procedure to extract an egg from an ovary may result in a painful infection developing in your pelvis. However, the risk of serious infection is very low. For example, there is likely to be less than one serious infection for every 500 procedures performed.
Having more than one baby may not seem like a bad thing, but it does significantly increase the risk of developing complications for both you and your children. Multiple pregnancy is the greatest health risk of fertility treatment.
Possible complications of multiple pregnancy include:
- Babies born prematurely or with a low birth weight – this affects 50% of twins and 90% of triplets.
- Your baby dying within the first week of life – the risk of this happening is five times higher for twins, and nine times higher for triplets, than for a single baby.
- Your baby having cerebral palsy (a condition that affects the brain and nervous system) – the risk of this happening is five times higher for twins and 18 times higher for triplets than for single babies.
- High blood pressure (hypertension) during pregnancy – this affects up to 25% of women who are carrying more than one baby.
- Developing [diabetes] during the pregnancy (diabetes is a condition caused by too much glucose in the blood) – the risk is two to three times higher for women carrying more than one baby than it is for those carrying a single baby.
Infertility can be stressful and strain relationships. It may be helpful for you to join a support group where you can talk through your feelings with others experiencing similar problems.
Finding out you have a fertility problem can be traumatic and many couples find it helpful to talk to a counsellor. The counsellor will be able to discuss treatment options, how they may affect you and the emotional implications. Your doctor should be able to refer you to a counsellor as part of your fertility treatment.
Read more about managing stress.