How does endometriosis affect IVF success rates?

Endometriosis is a serious condition which can severely impact fertility. It affects a significant percentage of women of childbearing age. Although modern medicine hasn’t yet established the precise cause of endometriosis, the link between the condition and lowered fertility has been clearly demonstrated. The problem with gauging the disorder’s precise impact is that it manifests itself differently in each patient – some experience severe pain and have significant difficulty conceiving, while others are asymptomatic and aren’t aware they have been affected.

For those afflicted with endometriosis, IVF is often presented as a potential way of achieving pregnancy. Why, though? Is the IVF process different for affected patients? Are success rates affected by the disorder?

To help us answer all of these questions – and more – we invited Dr Ruth Sánchez, a Gynaecologist at Pregen, the reproduction unit at Clinica Vistahermosa to explain a little more.

What is Endometriosis?

Endometriosis is a chronic and benign disease – simply put, it is the presence of endometrial tissue outside of the uterus. It affects between 6 to 10% of all women of reproductive age. Between 25 and 50% of women with fertility problems are affected by endometriosis, while around half of patients with endometriosis present with infertility issues.

The endometrial tissue most commonly ends up on the ovaries – as cysts – or inside the fallopian tubes, although implants on the uterine wall, bladder, abdomen – endometriosis sometimes makes it as far as the lungs! Depending on the location of the endometriosis, afflicted patients can experience painful menstruation or localised pain in case of the endometriosis making it all the way to the chest.

Endometriosis is different in each patient. To help sort it out, a four-stage classification system was devised – each stage corresponds to a certain level of severity, from stage I (minimal) to IV (severe).  Minimal and mild endometriosis – the first two stages – are the most common occurrences of the disorder, and often present either minimal and sporadic symptoms, or are asymptomatic altogether.

Almost half of all cases of endometriosis do not manifest any symptoms. For the other half, symptoms include:

• Pain – abdominal pain, painful menstrual cramps, pain during intercourse
• Infertility
• Location dependant:
  • Painful urination or the presence of blood in the urine
  • Pain when defecating, rectal bleeding
  • Chest pains, bloody coughs

These symptoms often intensify during menstruation and often go away following menopause or during pregnancy.

Endometriosis, Infertility and Treatment

Endometriosis can cause infertility in many different ways. Implants on the ovaries reduce the ovarian reserve and negatively influence the development of the oocytes. They can also lead to abnormal ovulations. Implants in the fallopian tubes can cause difficulties in transport or adhesions, while those in the endometrium often result in alterations of the immune system or abnormal endometrial receptivity. Endometrial implants also release toxic substances which can prove lethal to an embryo.

Properly diagnosing endometriosis often requires a clinical history in order to determine risk factors the patient may have been exposed to. Such risk factors include nulliparity, early first menstruation, heavy bleeding during short cycles, low BMI, alcohol use, history of gynaecological or obstetric surgery. Family history is also important, as those with first-degree relatives afflicted by the disorder are seven to ten times more likely to be affected themselves.

Physical examinations are also important, but endometriosis likes to hide itself; most affected patients present completely normal during normal testing. Despite this, some procedures, such as a transvaginal ultrasound, can reveal endometriosis – in this case, by helping doctors detect cysts on the ovaries. In selected cases, an MRI scan needs to be employed.

Ultimately, however, it is the laparoscopy which confirms the diagnosis. It is a surgery in which small incisions are used to allow a small surgical camera to examine a cavity for endometriosis. In some milder cases, endometrial implants can be removed during the laparoscopy, without having to schedule a completely different surgery.

There is no cure for endometriosis. It is a chronic disease for which the therapeutic approach depends on the patient’s priorities – treating either the pain, or the infertility.

For pain management, hormone therapy is the first and most common option – simply prescribing common contraceptives prevents heavy menstruation and relieves pain. Radical surgery is also an option, although it isn’t a cure-all: despite symptoms dissipating and life quality being improved, in 50% of cases the disorder can reoccur within five years. It can also permanently diminish the ovarian reserve.

Endometriosis and preserving the fertility

If the patient wants to preserve her fertility, surgical removal of lesions larger than 4 centimetres is possible, which improves spontaneous conception rates. In the case of IVF, it makes no difference – for patients considering IVF, the current trend is to not perform surgery and continue with early fertility treatments. However, surgery may still be indicated for IVF patients in specific circumstances; namely, if their ovarian reserve has been preserved, if they haven’t undergone surgery previously, if their disease is unilateral, and/or if they are experiencing rapid growth or lesions larger than five centimetres.

Endometriosis and getting pregnant

In patients with decreased ovarian reserve, or those in whom endometriosis reoccurred (following a surgery), or those whose disease is bilateral, it is recommended to go straight to IVF, as other surgical attempts may do more harm than good.

For patients affected by endometriosis, the first choice of treatment is usually IVF. It provides the best chances of success even though the treatment’s effectiveness is lower than in patients not affected by the disorder. This difference becomes larger the more severe the disorder. Fertilisation rates, implantation rates and the number of recovered eggs are all lower across the board in patients with endometriosis. In order to increase the pregnancy rates, patients can undergo hormone therapy lasting three to six months.

Other treatments include intrauterine insemination (IUI), which is usually attempted in cases of minimal or mild endometriosis, although pregnancy rates are usually low. Patients who have diminished ovarian reserves as a result of surgery, or those with multiple adhesions can opt for egg donation. Patients who are in the early stages of endometriosis can also consider freezing their eggs before the disorder progresses.