What causes infertility? A quick guide to Infertility Diagnoses

What causes infertility? A quick guide to Infertility Diagnoses

The causes of infertility are complex and varied; it can be caused by specific diseases such as PCOS and endometriosis or it can be unexplained or a physiological problem which prevents some part of the impregnation process. Currently the causes are broken down as 30% female, 30% male, 10% both, 25% unexplained and 5% other. Keep reading to understand more about the specific causes of infertility. 

What is this quick guide for diagnoses of infertility for?

This article is designed for as a quick reference towards the common key diagnoses and condition which can impact or cause infertility. This is designed to help give you a brief understanding of the condition what the fertility tests you may have, and a whistle stop tour of symptoms and treatment options.

These are not detailed guides about each condition but detailed factsheets about these will be linked under each condition where they exist. It will not cover the detailed exploration of symptoms and treatment, impacts on IVF treatment protocols and detailed mechanisms of disease.

What causes infertility? A look at the key diagnoses

Polycystic Ovary Syndrome (PCOS)

PCOS is a non-cyst enlargement of the ovaries, due to hormonal imbalances, it commonly affects the development and or the release of eggs. The number of women suffering with PCOS is unknown as many don’t have a formal diagnosis and different criteria are used in the diagnosis. Due to this it is unclear the prevalence of PCOS and estimates vary wildly from 2.2% – 26% of women suffer from PCOS – which is widely accepted as the most common endocrine condition that women suffer from. There are three key diagnostic criteria to Polycystic Ovary Syndrome as defined by the Rotterdam consensus criteria:

  1. Polycystic ovaries specifically 12 or greater follicles or increased ovarian volume specifically greater than 10cm3
  2. Oligo-ovulation or anovulation. Oligo-ovulation means that ovulation is irregular which can sometimes be indicated by a cycle outside the normal range 21-35 days. Anovulation essentially means that no ovulation occurs, this is broad and can be because the eggs don’t develop properly or that they aren’t released from the follicles. This can lead to no menstrual cycle for a lengthy period of time, or you can have a normal cycle but not ovulate.
  3. clinical and/or biochemical signs of hyperandrogenism. This is quite complex so we will keep the detail for another article. The specific biochemical test is the free androgen index this is calculated by total testosterone divided by sex hormone binding globulin [SHBG] x 100), there are many other conditions which can impact this which will also need to be ruled out. The key clinical sign is hirsutism which is often signified with excess facial and body hair and midline hair growth.

From the above you can see that the key diagnostic tests will be blood work, various ultrasound scans and a detailed medical history. If you want more information on fertility testing, see our article Fertility Investigations.

The most common symptoms of PCOS are: –

  • Changes in your menstrual cycle – either irregular or stopping completely
  • Difficulties in conceiving
  • excessive hair growth known as hirsutism
  • thinning hair and hair loss from the head
  • ache and oily skin

Unfortunately, treatments for Polycystic ovary syndrome is complicated and we can’t currently cure it. As such the treatments are focused on minimising symptoms. Possible treatments include: –

  • Lifestyle change to help manage weight and healthy living
  • Medication – these can be hormones to help with regular periods, promoting ovulation, keeping endometrial lining thin, to reduce unwanted hair growth, type 2 diabetes medications. These will be used for your own personal circumstances and to treat your symptoms.
  • Fertility treatments – Medication as above to support natural conception, but if that doesn’t work then options for cycles of in-vitro fertilisation (IVF)
  • Surgery – For medication resistant PCOS Laparoscopic ovarian drilling may be considered


Endometriosis is the non-desirable growth of the endometrial cells anywhere within the body. Current research indicates that approximately 1 in 10 women (link to research article) suffer with endometriosis to varying degrees, with the prevalence of endometriosis amongst those with infertility as high as 3 to 5 in 10 (link to research) depending upon the stage.

Endometriosis is not able to be officially diagnosed through you’re GP, an ultrasound or any other non-intrusive procedures. This means that GP’s and specialists are often reluctant to perform the diagnostic procedure. This can mean that people who are struggling with the pain and difficulties can live with the condition for years and have to self-advocate to get to see the right specialist or have the laparoscopy procedure.


As mentioned the only way to diagnose endometriosis is through a laparoscopy, which is a small incision under general anaesthetic using a camera to identify any unwanted endometrial cells.

The most common symptoms of Endometriosis are: –

  • Pain – Severe pain during your period, pain during sex or ovulation or generalised pelvic pain, back or leg pain.
  • Bleeding – Heavy bleeding during your period sometimes with clots, loss of old or dark blood before your period begins, longer periods or spotting in between periods or irregular menstruation.
  • Bladder or bowel problems – pain when urinating or before/after urination or a bowel motion, painful bowel motions, bleeding from the bowel, diarrhoea, constipation or bloating.
  • Ongoing tiredness
  • Depression
  • Infertility

Treatment for endometriosis is limited, mostly focused around the control of symptoms such as pain. However, there are a couple of more invasive options. Possible treatments include: –

  • Pain relief – pain killers (such as anti-inflammatory or codeine), use of heat (e.g. hot water bottle) to area of pain, TENS machine (transcutaneous electrical nerve stimulation), pain modifying drugs such as certain anti-depressants which help reduce the number of pain messages reaching the brain and physiotherapy.
  • Hormone treatment – Hormone treatment can prevent further growth, but it will not do anything for existing adhesions. There are two types of treatment, the first puts your body into a state similar to the menopause and the second into a permanent state of mimicking pregnancy. These are reversed when the treatment is stopped. It is important to note that this treatment won’t help with fertility issues.
  • Surgery – Surgery is used to remove endometriosis, adhesions and cysts. There are multiple surgical options available, with conservative option being the first point. The aim is to remove as much as possible from the specific area’s affected, if there are multiple organs involved then a multidisciplinary team will be used, most of these surgeries are done laparoscopically. If an individual doesn’t want to start a family or already has or in extreme cases a radical approach may be needed such as a hysterectomy (removal of the womb) or oophorectomy (removal of the ovaries)

Premature Ovarian Insufficiency (often known as premature ovarian failure)

The menopause (last menstrual period) normally occurs between 47-52 on average. In lay terms POI is getting your menopause years or decades earlier then normal. It means that they stop producing eggs properly; this also means that the hormones created by ovaries are often affected and they are very important in women’s health. Premature Ovarian Insufficiency affects about 1 in 100 under 40, 1 in 1000 under 30 and 1 in 10,000 under 20 will experience POI.

Cancers, surgery, genetics and auto immune conditions can cause POI, however 90% of cases don’t have an identifiable cause, these are known as idiopathic or spontaneous POI. The video to the right gives a solid overview of POI.

Diagnosing POI is in theory relatively straight forwards it looks at:

  • Blood tests to look at the levels of FSH (Follicular Stimulating Hormone) and LH (Luteal Hormone) If these are elevated to within the menopausal range (FSH greater than 30iU/l – coupled with a history of no menstruation then POI should be considered.
  • This can be further explored with a pelvic ultrasound to rule out other potential conditions and to look at the number of follicles in the ovary which in POI will be low.

The issues is that G.P’s and non-specialists put irregular or stopped menstruation down to stress, weight change and other gynaecological conditions and as such don’t perform these tests.

The most common symptoms experienced by Premature Ovarian Insufficiency are: –

  • Irregular or stopped menstruating – This is most commonly what makes people aware something is not right
  • Infertility – This is the other key one which will bring people to get tested
  • Hot flushes and night sweats
  • Insomnia/disrupted sleep
  • Mood swings and irritability
  • Weight gain – This is most common around the midrift
  • Lowered sex drive – This can cause relationship and mental health challenges as well

There is no cure for POI and the condition has to be managed effectively to reduce long term risks to the Brain, cardiovascular system and the bones. The main treatment option is hormone replacement therapies (oestrogen & progesterone) or the combined oral contraceptive, both have been shown to be successful in the treatment of POI symptoms. Some women with sexual dysfunction and mental heath issues related to loss of fertility should be provided with access to psychosexual counselling and testosterone replacement therapy if needed.

Finally, it is rare that someone suffering with POI can conceive naturally, some who have idiopathic POI and occasionally ovulate have got pregnant naturally the small amount of research on this indicates around 5%. Most of the time IVF with donor eggs is the option available to POI suffers.


Fibroids don’t always impact fertility, the impact on fertility is often determined by the location and size. Those fibroids most likely to impact fertility are submucosal (meaning they are within the uterine cavity) or are greater than 6 cm in diameter intramural fibroids (those found in the walls of the uterus)

Approximately 5-10% of women of reproductive age have fibroids and few people have those which seriously impact fertility however those that do, named above, can prevent the sperm from getting to the egg, the egg implanting, the viability of a pregnancy and the position and growth of the baby. Therefore, it is important that a specialist is involved if you have fibroids which may impact fertility or pregnancy.

Often women with fibroids are asymptomatic (don’t experience symptoms) which means the fibroids are only picked up during a scan or gynaecological examination. For those that do experience symptoms about 1 in 3 people will get some or many of these: –

  • Frequent need to urinate
  • Painful and or heavy periods
  • Stomach and or lower back pain
  • constipation
  • Discomfort or pain during intercourse

The image on the right, shows an image of a fibroid in using a hysteroscope. 

Treatment of Fibroids is often not needed if you are asymptomatic, or you experience minor symptoms which don’t impact your day to day life. If you have moderate to sever symptoms then treatment may be required, there are a lot of treatment options which will be looked at depending upon your specific circumstances and whether you are wanting to try and conceive, these include: –

  • Medication – There is a huge variety of medications which are prescribed based upon your specific symptoms and the classification of your fibroid. These can be hormone replacement therapies, medications to reduce bleeding, medication to shrink fibroids.
  • Surgery -There are 3-4 surgical options for severe endometriosis, however these should only be considered for sever cases and those that are resistant to medication. These can include Hysterectomy, Myomectomy (removing the fibroid from the womb of the wall), Hysteroscopic resection (using a hysteroscope and small surgical instruments to remove the fibroids), Hysteroscopic morcellation (similar to the resection, but specialist training in the use of a  morcellator which cuts it into small pieces, the advantage is the equipment is only inserted once to minimise risk).
  • Non-Surgical procedures
    1. Uterine artery embolisation (UAE)- In lay terms they use a catheter to block the blood flow to the fibroid – point of note there is not a lot of research into the impacts on fertility of this procedure.
    2. Endometrial ablation – This is a relatively simple procedure which removes the lining of the womb. It is not recommended for those wanting children as it comes with high risks of complications including miscarriage
    3. Two fairly recent MRI based techniques called MRI-guided percutaneous laser ablation and MRI-guided transcutaneous focused ultrasound where they use sound or lasers to destroy the fibroid, again there is little research into the impacts of fertility and pregnancy so discuss this with your specialist.

Unexplained Fertility

We will just touch on this, approximately 25% of infertile couples are diagnosed with unexplained infertility. This essentially means we currently don’t know the cause of your infertility. Current technology or available testing doesn’t allow for the medical teams to confirm a specific reason. Some research articles such as the 2008 Diagnosis and Treatment of Unexplained Infertility (link to research article) state that it could be that unexplained fertility is the lower extreme of normal distribution or, it could also be imagined that the routine infertility evaluation misses subtle defects because of imperfect or incomplete testing methods. Either way at this current point the evidence indicates that IVF treatment seems to be the most reliable treatment for unexplained fertility.

Let’s quickly take a quick look at what unexplained fertility is not:

  1. It’s not a psychological or psychosomatic problem as some seem to believe
  2. It can’t be solved by not trying as hard and stress
  3. It is not a non-issue

The fact that after sustained periods of trying to conceive you are statistically very unlikely to have not conceived means that it is worth taking note of. The emotional journey of struggling to conceive can actually be even more intense because you have no answers and you will always wonder why.

Male Infertility Diagnosis

In some respects, male infertility diagnosis are less clearly defined than those affecting women. Male infertility is generally broken down into three categories

  1. Problems with ejaculation or erection – This can be Ejaculatory Duct Obstruction which means that sperm aren’t present in the ejaculate this can be caused by scar tissue, stones, cysts. Inability to ejaculate this can be caused by nerve damage, surgery, diabetes. Retrograde ejaculation which is where a man ejaculates into the bladder, this is most often a physiological issue and semen can be extracted for IVF using a rectal probe to stimulate a reflex ejaculation.
  2. Problems within the fine, small reproductive tract ducts this is known as Varicocele which can mean the temperature around the testicles can be too high and can impact upon sperm production. This condition can also cause pain in the testes which can worsen during physical activity.
  3. Problems with sperm production – These are often down to lifestyle issues and or hormonal imbalances and will be treated as such with lifestyle advice and hormone replacement therapies if required.

Assisted reproduction is often required in male infertility especially if it is heavily impacting the motility, mortality or normal forms of your sperm and you may need to have ICSI (Intracytoplasmic sperm injection) as part of you IVF cycle which means that the embryologist will select a healthy looking sperm and directly inject it into the egg.


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