How does endometriosis affect a woman’s fertility?

By (gynecologist), (gynecologist), (embryologist) and (embryologist).
Last Update: 08/18/2021

Endometriosis is a fairly common disease in women of reproductive age and it is also linked to fertility problems. Approximately 30% to 50% of patients with endometriosis are infertile or have a problem achieving a natural pregnancy.

This uterine alteration is characterized by the presence of endometrial tissue outside the uterus. Among its associated consequences are a lower oocyte quality, which affects the fertilization rate and the quality of the embryos.

Therefore, assisted reproduction has greatly helped these women achieve pregnancy with endometriosis, especially techniques such as in vitro fertilization (IVF) and ovodonation.

Provided below is an index with the 7 points we are going to expand on in this article.

Causes of infertility due to endometriosis

Although the causes of endometriosis are still a bit unclear, there are now several studies that explain why endometriosis affects fertility. However, it is important to consider the degree of endometriosis, as it is a factor in trying to get pregnant.

The main causes of this pathology are discussed below.

Anatomical causes

Primarily, the ovaries and fallopian tubes are affected by the growth of endometrial tissue outside the uterus.

In the ovary, endometrial adhesions are destroying healthy tissue, which affects the ovarian reserve, hinders the normal development of follicles and oocyte maturation. In addition, these endometrial cysts can also prevent ovulation.

When endometriosis appears in the uterine tubes, it interferes with tubal patency. This makes it impossible for the egg to pass and be transported through the tube when it is released from the ovary, so it is not fertilized and does not reach the uterus.

Apart from fallopian tube patency, the fallopian tubes may have another difficulty due to the increased volume of peritoneal fluid and the presence of oocyte capture inhibitors. The consequence of this is that the fimbriae in the tube cannot interact with the egg and the egg cannot reach the tube after ovulation.

Decreased endometrial receptivity

Female sterility can also be due to alterations of the immune system. IgG and IgA antibodies, as well as lymphocytes, are increased in the blood, which may affect endometrial receptivity and embryo implantation.

Embryo implantation capacity may also be diminished because patients with endometriosis have problems synthesizing endometrial ligament and, in addition, the levels of integrins (cell adhesion molecules for implantation) are very low.

Finally, endometrial lesions or endometriomas can secrete toxic substances that affect both the egg and the sperm.

Endometriosis and natural pregnancy

The first option for women with endometriosis to recover their fertility and be able to have children with a natural pregnancy is medical and/or surgical treatment, depending on the degree of affectation and the medical history of each patient.

Endometriosis can be differentiated into 4 degrees depending on the location, quantity, depth and size of the endometrial implants:

  • Grade I or minimum grade.
  • Grade II or mild grade.
  • Grade III or moderate grade.
  • Grade IV or severe grade.

Pain relievers and hormone treatments are effective in relieving pain and regulating menstrual cycles. However, laparoscopic surgery will be necessary to improve fertility and increase the chance of pregnancy. Above all, they are effective treatments in mild endometriosis for a natural pregnancy.

Laparoscopic surgery is a minimally invasive technique in which a laparoscope is inserted to view the abdominal cavity through a small incision.

In the most severe cases of endometriosis, when women have endometriomas or ovarian cysts, also called chocolate cysts, it is advisable to perform a laparoscopic cystectomy to remove these cysts. This has been shown to increase pregnancy rates.

Endometriosis and fertility treatments

If pregnancy does not come after surgery and after having tried for at least a year, assisted reproduction techniques are a hope for those women who see their motherhood at a distance.

To perform a PGD, one should undergo IVF as the main treatment. If you are looking for a clinic to get started, we recommend that you generate your individual Fertility Report now. It is a useful, simple tool that, in just 3 steps, will give you a list of the clinics that have passed our rigorous selection process. You will receive an email in your inbox with a report that contains tips and recommendations to get started.

Depending on the severity of the endometriosis and the evolution of the treatments, the appropriate techniques will be one or the other:

Artificial insemination.

Artificial insemination (AI) is indicated for young patients with mild endometriosis (grade I and II).

Normally, the patient is given hormones before insemination. These hormones used for ovarian stimulation improve the prognosis of women with endometriosis. Obviously, for AI to be effective, the tubes must be unobstructed and the sperm must be allowed to interact with the egg.

We advise you to access the following link to get all the information about this assisted reproduction technique: What Is Artificial Insemination (AI)? - Process, Cost & Types.

In vitro fertilization

IVF is the technique of choice for patients with endometriosis with greater involvement, i.e. type III or IV endometriosis. IVF is also indicated when AI has previously failed in women who had a better prognosis.

This reproductive option offers a higher gestation rate in women with endometriosis than if AI is performed. However, specialists recommend trying a first insemination in women who meet the requirements due to the simplicity of the technique.

If you want to continue reading more information about this topic, we recommend you to visit the following article: What Is In Vitro Fertilization (IVF)? - Process, Cost & Success Rates.


In the IVF laboratory it has been observed that both eggs and embryos from patients with endometriosis have a worse morphology. In addition, fertilization and the subsequent development of the embryo have also been affected.

For this reason, women with severe endometriosis and/or several failed IVF cycles are forced to resort to ovodonation as a last option to have children. In fact, 10% of donor egg recipients are patients with endometriosis.

As the specialist in Gynecology and Obstetrics, Dr. Blanca Paraiso, tells us in the interview about endometriosis:

Ovodonation pregnancy rates in women with endometriosis and women without endometriosis are the same.

In addition, ovodonation is also indicated in cases where endometriomas of the ovary prevent follicular puncture to retrieve the eggs.

Fertility preservation

Since endometriosis is a progressive disease and a woman's age also aggravates the infertility situation, women diagnosed with endometriosis are advised to vitrify their eggs if they wish to have children in the future.

Thanks to the vitrification technique, the eggs can be stored for an indefinite period of time without altering the quality with which they were frozen. In this way, the quality of the eggs is not diminished so that the IVF treatment is more successful.

In addition, it should be remembered that ovarian reserve is also affected with endometriosis. This means that endometriosis can cause a decrease in a woman's available eggs and thus reduce her chances of pregnancy.

FAQs from users

Do all women with endometriosis have fertility problems?

By Sara Salgado B.Sc., M.Sc. (embryologist).

No. Endometriosis can cause infertility, but not all women with endometriosis will experience infertility. It will depend mainly on the degree of involvement and the area(s) affected.

Which is more effective with mild endometriosis, IUI or IVF?

By Manuel Aparicio Caballero M.D., M.Sc. (gynecologist).

Intrauterine Insemination (IUI) is the treatment of choice for young patients with mild-to-moderate endometriosis (stages I and II). For this treatment to be possible, no blockage in the Fallopian tubes must exist. However, recent studies suggest that IUI may be ineffective in these cases. The latest European review on the average success rates during years 2016-2017 with AIH (artificial insemination by husband) are below 15% per cycle. So, in conclusion, opting for IUI in cases of mild-to-moderate endometriosis is possible in very particular cases where there is evidence that it might work.

In general, In Vitro Fertilization (IVF) is the first option for patients with a moderate or severe type of endometriosis (stages III and IV), as well as for women with previous failed cycles in spite of having a good prognosis initially.

Why does endometriosis cause infertility?

By Sara Salgado B.Sc., M.Sc. (embryologist).

Since it is a disease whose cause is unknown and is related to other alterations and pathologies that can also affect fertility, it is difficult to establish why infertility can occur.

In any case, it has been observed that endometriosis can negatively affect the eggs (ovarian reserve), the fallopian tubes and embryo implantation.
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Does endometriosis get better with pregnancy?

By Zaira Salvador B.Sc., M.Sc. (embryologist).

Pregnancy does indeed have a protective effect on endometriosis. This is due to the halt of the woman's menstrual cycle and the decrease of oestrogen, hormones involved in the growth of endometriomas. Therefore, during pregnancy, the woman feels relief from symptoms and pain. Unfortunately, this all resumes once the woman has given birth.

Can endometriosis cause cancer?

By Zaira Salvador B.Sc., M.Sc. (embryologist).

It has been estimated that only about 1% of endometriosis sites develop into malignant tumours, i.e. cause cancer. However, further studies are needed to confirm this prevalence.
Read more

Can complications arise as a result of endometriosis?

By Zaira Salvador B.Sc., M.Sc. (embryologist).

Yes, the most prominent is infertility. It is also possible for endometriosis to result in chronic and prolonged pelvic pain, with the appearance of large cysts in the pelvis. Much less frequently, obstruction of the gastrointestinal tract or urinary system, as well as cancer may occur in areas of endometriosis after menopause

Is endometriosis synonymous with infertility?

By Marta Barranquero Gómez B.Sc., M.Sc. (embryologist).

No. Endometriosis is a possible cause of female infertility. However, this does not mean that all women with endometriosis will have fertility problems.

The difficulty in achieving pregnancy will depend on the degree of severity of the endometriosis and the different areas affected by the presence of endometrial tissue. It is not the same to have a grade I endometriosis as it is to have a grade IV endometriosis, where it is most likely that you will have to resort to ovodonation to fulfil your desire for motherhood.

Suggested for you

Ovarian reserve can be affected as a result of ovarian endometriosis. To find out how this influences a woman's fertility, click here: How Many Eggs Does a Woman Have? - Your Egg Count by Age.

We have talked about fertility preservation as a method to avoid the deterioration of oocyte quality. If you want to know what this method consists of and the prices it has in Spain, you can continue reading here: Fertility Preservation - Cost & Options for Retaining Your Fertility.

We make a great effort to provide you with the highest quality information.

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FAQs from users: 'Do all women with endometriosis have fertility problems?', 'Which is more effective with mild endometriosis, IUI or IVF?', 'Why does endometriosis cause infertility?', 'Does endometriosis get better with pregnancy?', 'Can endometriosis cause cancer?', 'Can complications arise as a result of endometriosis?' and 'Is endometriosis synonymous with infertility?'.

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Authors and contributors

 Blanca Paraíso
Blanca Paraíso
M.D., Ph.D., M.Sc.
Bachelor's Degree in Medicine and Ph.D from the Complutense University of Madrid (UCM). Postgraduate Course in Statistics of Health Sciences. Doctor specialized in Obstetrics & Gynecology, and Assisted Procreation. More information about Blanca Paraíso
License: 454505579
 Manuel Aparicio Caballero
Manuel Aparicio Caballero
M.D., M.Sc.
Bachelor's Degree in Medicine from the University of Murcia. Specialist in Obstetrics & Gynecology. Master's Degree in Human Reproduction from the King Juan Carlos University and the IVI. More information about Manuel Aparicio Caballero
License: 303008030
 Marta Barranquero Gómez
Marta Barranquero Gómez
B.Sc., M.Sc.
Graduated in Biochemistry and Biomedical Sciences by the University of Valencia (UV) and specialized in Assisted Reproduction by the University of Alcalá de Henares (UAH) in collaboration with Ginefiv and in Clinical Genetics by the University of Alcalá de Henares (UAH). More information about Marta Barranquero Gómez
License: 3316-CV
 Zaira Salvador
Zaira Salvador
B.Sc., M.Sc.
Bachelor's Degree in Biotechnology from the Technical University of Valencia (UPV). Biotechnology Degree from the National University of Ireland en Galway (NUIG) and embryologist specializing in Assisted Reproduction, with a Master's Degree in Biotechnology of Human Reproduction from the University of Valencia (UV) and the Valencian Infertility Institute (IVI) More information about Zaira Salvador
License: 3185-CV

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