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How does endometriosis affect fertility?

Getting pregnant when you have endometriosis can be more difficult than usual but around 7 in 10 women with mild to moderate endometriosis conceive without treatment.

What is endometriosis?

Endometriosis is a common condition in which small pieces of tissue that are similar in make-up to the inner lining of the womb (endometrium) grow outside of the womb; for example on the bowel or bladder, ovaries and fallopian tubes and on the lining of the abdomen.

It is thought to affect around two million women in the UK but it is difficult to be sure because some women have no symptoms. Women of child bearing age are affected most commonly. It is not a cancer. You are more likely to have it if your mother or sister had it. It is linked to infertility.

Symptoms of endometriosis

Symptoms can vary with some women not having any at all, and others having very severe pain. The most common symptoms are:

  • painful, heavy or irregular periods
  • pain in the lower abdomen, pelvis or lower back around ovulation time, but also throughout the cycle
  • ongoing pelvic pain lasting six months or longer
  • pain during or after sex
  • difficulty getting pregnant
  • painful bowel movements and emptying of bladder

Women have also reported some other symptoms, which include:

  • bleeding from the back passage
  • tiredness/fatigue
  • painful abdominal scars or pain around belly button, especially during the menstrual period
  • coughing blood (very rare)

The severity of symptoms is often not directly connected to how much disease tissue you have. You can have severe symptoms and only a few spots. Or a lot of endometriosis but no or only a few symptoms.

Keeping a pain and symptom diary can help with diagnosis.

Although some women might not even realise they have endometriosis until they are checked when they have difficulty getting pregnant, others are in great ongoing pain throughout their lives and have rounds of surgery to manage the condition.

How endometriosis is diagnosed

As the symptoms of endometriosis are similar to a range of other conditions, it can be hard to get a diagnosis but if you have one or more symptoms from the first list above, your doctor should suspect endometriosis and offer you an abdominal and pelvic exam.

  1. The doctor manually feels (palpates) areas in your pelvis and abdomen for abnormalities, such as cysts on your reproductive organs or scars behind your uterus.
  2. If your symptoms are severe and persistent and/or the pelvic/abdominal exam shows symptoms of endometriosis then you may be referred for an ultrasound scan. This can be done through the abdomen or using a ‘wand’ inserted into your vagina (transvaginal ultrasound). Even if the scan shows no signs, you may be referred for a laparoscopy if your symptoms are severe and persistent.
  3. Your doctor may refer you to a surgeon to look inside your abdomen for signs of endometriosis using a surgical procedure called laparoscopy. While you're under general anaesthetic, the surgeon makes a tiny cut near your navel and inserts a small thin lit tube called a laparoscope, looking for endometrial tissue outside the uterus. They may take samples of tissue. Laparoscopy can provide information about the location, extent and size of the endometrial tissue (called implants). If a full systematic laparoscopy doesn’t show any signs, then you do not have endometriosis.

Stages/severity of endometriosis

The American Society of Reproductive Medicine has developed a staging system to classify the severity of endometriosis. The system for defining the stages of the endometriosis looks mainly at how much tissue has grown and where it is, so it doesn’t always reflect the amount of pain you might have or the risk of infertility. It’s possible for a woman in stage 1 to be in pain for example, while a woman in stage 4 has no pain at all.

  • Stage 1: Minimal
  • Stage 2: Mild
  • Stage 3: Moderate
  • Stage 4: Severe

Endometriosis treatment in the UK is usually not based on the stage of endometriosis but on symptoms and your own life priorities. If you want to have a baby then your treatment will be different to the treatment of a woman who is not trying to get pregnant because some treatments prevent pregnancy.

Surgery to remove endometrial tissue could improve your chances of pregnancy if it is thought to be preventing this.

What causes endometriosis?

The cause of endometriosis is still unknown however there are some theories which include:

  • Retrograde menstruation: The term for when some of the lining of the womb flows backwards through the fallopian tubes and into the abdomen rather than leaving the body as a period. This occurs in most women as a normal monthly process, but normally the body clears the tissues naturally. However, for some this tissue attaches onto pelvic or abdominal organs or wall resulting in endometriosis. It is unclear though why this happens in only some women.
  • Genetics: It is more common to be affected by endometriosis if a female member of your family (especially a parent or sibling) has endometriosis. It can occur in women of all ethnicities but is more common in Asian women than white women and it is less common in women of African-Caribbean origin.
  • Immune system: It may be that some women’s immune system is not able to get rid of the tissue therefore women with low immune system may be more at risk of endometriosis
  • Environmental: Certain toxins in the environment that affect the immune systems and reproductive system are thought to cause endometriosis but this has not been proven in humans yet.
  • Lymphatic or circulatory spread: It is possible that some cells of the tissue can travel around the body in the bloodstream or other vessels to different parts of the body
  • Metaplasia: This occurs when one type of cell can change and become a different kind of cell; the cause of this is largely unknown.

How endometriosis affects fertility

Although endometriosis can have an effect on your chances of getting pregnant most women who have mild endometriosis are not infertile. An estimated 70% of women with mild to moderate endometriosis will get pregnant without treatment. If you know you have endometriosis and are failing to conceive, talk to your doctor who can advise you or refer you to the necessary fertility specialists.

The exact nature of the link between infertility and endometriosis is unclear but the severity of the condition and location of the tissue appears to have an effect. For example, it is not fully known how a few spots of endometriosis may affect your chances of getting pregnant, but if you have severe endometriosis your chances are likely to be affected by the changes to your anatomy. However, even with severe endometriosis natural conception is possible.

If you have endometriosis and are trying to get pregnant without success, it is important that you get help and support so speak to your doctor about being referred to a gynaecologist or a fertility specialist .

Getting pregnant with endometriosis - treatment

There is no cure for endometriosis but there are treatments to help manage the condition. 

Managing the pain

If your endometriosis causes pain and you are taking painkillers, such as non-steroidal anti-inflammatories (NSAIDs), paracetamol or Codeine. You will be advised to stop taking NSAIDs and minimise the use of codeine as they may have an effect on the baby if you conceive.

Hormonal treatments

There are lots of different types of hormonal treatments that can be offered to those who have endometriosis however as they either mimic pregnancy (such as the contraceptive pill) or menopause they are not suitable if you are trying to get pregnant.

Surgery to improve fertility with endometriosis

For those with minimal or mild endometriosis surgery can improve fertility and should be discussed with you if you are finding that you are not able to get pregnant and the condition has been found to be a possible cause of your infertility.

  • The most common type of surgery is laparoscopy, also known as keyhole surgery. This involves a thin tube with a camera at the end being inserted into your abdomen through a small cut made in your skin, usually your belly button. Through this camera and possibly additional small cuts around your bikini line either laser or heat or scissors can be passed to remove or destroy the tissue. For this procedure, you will be put to sleep under general anaesthetic so you will not feel any pain. This is an effective treatment but there is a risk of some tissue being left behind or re-growing, so the endometriosis can recur.
  • The other type of surgery that can be performed is a laparotomy. This surgery should only be done in very few exceptions as is more invasive with a wider cut along the bikini and removal of the tissue attached to the affected area. Centres of expertise in the UK, organised by the British Society of Gynaecological Endoscopy, are usually able to perform most surgeries using the keyhole method.

Endometriosis can grow back after surgery. Whether this is because it was not fully removed in the first place or whether it re-grew is impossible to tell. However, it does not mean that if endometriosis ‘regrows’ that it will also cause symptoms. Recurrence rates are about 50% over five years.

How long should someone wait until after a laparoscopy to try to conceive?

There is no easy answer to the question of how soon to try to conceive after a laparoscopy. It depends on factors such as how much tissue was removed, where it was removed from, age and previous infertility or babies.

Are there any reliable statistics on chances of conceiving after successful surgery?

The best way of assessing the chances of natural conception is the so-called endometriosis fertility index (EFI), which takes into account factors such as length of infertility, extent of disease and whether the fallopian tube is involved, age and whether or not a pregnancy had occurred in the past. This index should be calculated after the operation by the surgeon.

IVF and endometriosis

Assisted reproductive techniques (ART) such as Intrauterine Insemination IUI) or In Vitro Fertilisation (IVF) are established treatments for endometriosis-related infertility. NICE recommends that IVF is offered after two years of unsuccessfully trying for a baby with endometriosis, assuming other factors such as semen quality and ovulation are normal. The chances of success are lower depending on how severe the endometriosis is however.

Endometriosis, diet and conceiving

Although there are many references in online forums to diet and endometriosis there is little actual research evidence that any foods in particular should be avoid or included in your diet to help with getting pregnant with endometriosis. Reviews of the research that has been carried out have concluded that the results have not shown that diet has an effect. More research into endometriosis and diet has been recommended by NICE.

For your own physical and mental wellbeing however eating a healthy balanced diet with plenty of fresh fruit and vegetables is always advised, along with drinking plenty of water.

Endometriosis and miscarriage

The effect of endometriosis on miscarriage after natural conception is still unclear.

Randomised controlled trials (RCTs) are the highest level of scientific evidence available. To date, there are only two that have looked at endometriosis and miscarriage. Both of these trials studied the effect of key-hole surgical treatment of mild endometriosis on miscarriage, comparing them to a women who did not receive surgical treatment. When the results of these two trials were put together, there was no reduction in the miscarriage rates, suggesting that the treatment of endometriosis has no impact on miscarriage.

There are also two large population-based databases, however, that do suggest that endometriosis is linked to miscarriage. The first is from a Sweden and looks at 24,667 women with endometriosis, and 98,668 women without endometriosis.

It shows that women with endometriosis were 20% more likely to miscarry compared to women that did not. The second database is from Scotland and compared 5,375 women with endometriosis and 8,710 women without endometriosis.

They also found that women with endometriosis are at higher risk of miscarrying compared to those without.

In summary, whilst the randomised controlled trials showed that the treatment of endometriosis had no impact on miscarriage rates, the large population-based databases showed a clear link between the two. With this conflict it is impossible to make a conclusion on whether endometriosis leads to miscarriages or not. There is therefore a great need for higher quality research in order to help us establish whether endometriosis truly has a part to play in miscarriage.

Endometriosis and pregnancy

Complications of endometriosis during pregnancy are rare but there is an increased risk of placenta praevia (low-lying placenta), in which the placenta attaches lower down in the womb. It is also linked to ectopic pregnancy.

Endometriosis and your mental wellbeing

If you have endometriosis that comes with severe symptoms, you will be know that it is a debilitating and life-changing condition, with women often undergoing numerous operations and struggling to conceive. It can have a huge effect on your mental wellbeing, which is often worsened by the fact that there are few external signs of the pain and impact. It is difficult for other people, including employers and managers, to understand what you are going through, and this can mean that they are less sympathetic to your suffering. Endometriosis UK is a charity that supports women living with the condition.

If it is affecting your mental wellbeing to the point where you think you might be experiencing anxiety or depression, talk to a doctor.

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Review dates
Reviewed: 04 September 2017 | Next review: 04 September 2020

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