Spontaneous Miscarriage In Women With Endometriosis

Image courtesy of imagerymajestic at FreeDigitalPhotos.net

Image courtesy of imagerymajestic at FreeDigitalPhotos.net

By I.Soussis MD

If women suffering with endometriosis have a higher risk of adverse pregnancy outcome in early pregnancy, such as spontaneous miscarriage or ectopic pregnancy, was not well documented up to now.

A study from Japan compared 49 pregnant women with endometriosis to 59 without the disease. They found that the incidence of spontaneous miscarriage was not  statistically significant different among the two groups. (18,4% in women with and 18,6% in women without endometriosis). Obviously in this study the numbers are small and its statistical power is rather weak.

Aris  studied the impact of endometriosis  on adverse pregnancy outcome in the Eastern Townships of Canada, over a 12 year period. The pregnancies studied were 31068 and of those 784 were in women with endometriosis (2,5%). In 183/784 pregnancies in women with endometriosis, an adverse outcome was recorded (23,3%). The risk of spontaneous miscarriage in women with endometriosis was statistically significant higher than the general population. The risk of miscarriage was almost twice than in women without endometriosis (1,89).

Saraswat et al. presented in Lisbon at the annual meeting of ESHRE 2015, an extremely interesting linkage analysis of the Scottish national registry. They studied 14655 women discharged from all Scottish national hospitals over a period of 30 years (1981-2010). They compared the pregnancy outcome in  5375 women with surgically confirmed endometriosis to 8280 women without endometriosis, who were pregnant at the same period. The chance of adverse pregnancy outcome in the first trimester was significantly higher in women with endometriosis. More specific the risk of spontaneous miscarriage was 1,7  and the risk of ectopic pregnancy was 2,7 times higher, than in women without endometriosis.

The statistical power of the last two studies is extremely strong. Indeed Saraswat et al. studied the whole population of Scotland over a long period of time.

Conclusions: The presence of endometriosis increases the risk of spontaneous miscarriage and ectopic pregnancy. Women with endometriosis should be followed closely in the first trimester of pregnancy. They should also be informed of the increased chances of adverse pregnancy outcome.

Eur J Obstet Gynecol Reprod Biol. 2014 Jan;172:36-9. doi: 10.1016/j.ejogrb.2013.10.024. Epub 2013 Oct 31. Endometriosis and pregnancy outcome: are pregnancies complicated by endometriosis a high-risk group? Mekaru K1, Masamoto H2, Sugiyama H2, Asato K2, Heshiki C2, Kinjyo T2, Aoki Y2.

Gynecol Endocrinol. 2014 Jan;30(1):34-7. Doi:10.3109/09513590.2013.848425. Epub 2013 Oct 17.  A 12 year cohort study of adverse pregnancy outcome in Eastern Townships of Canada: impact of endometriosis. Aris A.

ESHRE 2015, O-122. Reproductive and pregnancy outcomes in women with endometriosis: a Scottish national record linkage study L.Saraswat, D.Ayansina, S.Bhattacharya, D.Miligkos, A.Horne, K. Cooper, S. Bhattacharya.

How successful is IVF treatment in women with endometriosis?

By I.Soussis

During the early days of IVF treatment, patients were placed into two groups; one which dealt with tubal factors and which was considered to have a better outcome and a second one, which encompassed all other causes of infertility.  Patients with endometriosis were placed into this second group, with a less favorable prognosis.

Women with endometriosis do not respond as well to ovarian stimulation, producing less oocytes, less embryos and have a smaller percentage of implantation.  Most doctors report a lower number of pregnancies for them.

This bias regarding the outcome of IVF treatment in women with endometriosis, was reinforced in 2002, by a study carried out by Barnhart et al.

This meta-analysis of 22 published studies showed that those women with slight endometriosis, had a similar percentage of pregnancies to those with tubal problems.  However, those with severe stage 3-4 endometriosis, had a 50% lower pregnancy rate.  The major flaw of  this study though is, that it was based on studies performed from 1980-1999, days in which drug protocols, as well as the procedures used in the laboratory, were very different and much less successful.

Therefore the question remains. Is it true that women with endometriosis have a lower pregnancy rate during IVF treatment?

The answer is definitely NO.

By studying National IVF registries that follow all IVF cycles on a yearly basis, the results clearly show that patients with endometriosis have an exceptional number of births, even higher than those with tubal factors.

Τhe CDC in the USA, the FIVNAT in France and the HFEA in the UK are responsible for the collection of IVF cycles in their jurisdiction and the maintenance of these huge databases.

Births according to the cause of infertility  CDC 2012

Births according to the cause of infertility
CDC 2012


The first graph from the CDC, represents the outcome of 400.000 IVF cycles in the USA in 2012.  The number of births from women with endometriosis is 31.1%, which is much higher than those with tubal factors of 28.5 %.


Birth rates according to the cause of infertility FInvat France

Birth rates according to the cause of infertility
FIvnat France

The second graph from France (FIVNAT) shows the results of about 250.000 IVF cycles from 1998-2002.  The births by women with endometriosis is 24% compared to 21% from women with tubal factors.

The statistical power of these huge numbers can not be matched by any study.

Therefore, in reality, women with endometriosis have exceptional results with IVF treatment.  They may have less oocytes or embryos, but the percentage of births is outstanding.  It is a quantitative matter and not a qualitative one.


Fertil Steril. 2002 Jun;77(6):1148-55. Effect of endometriosis on in vitro fertilization. Barnhart K1Dunsmoor-Su RCoutifaris C.

Smoking and endometriosis

Image courtesy of pat138241 at FreeDigitalPhotos.net

Image courtesy of pat138241 at FreeDigitalPhotos.net

By I.Soussis

The relationship between smoking and endometriosis is not very clear.  The conclusions of many studies are rather conflicting and opposing.

In a study from Portugal, women who smoked or had stopped smoking, had a smaller chance of getting endometriosis, than non smokers.

A Turkish study found just the opposite from the Portuguese one.

In the USA infertile women with endometriosis were compared to fertile women.  With regards to smoking, there was a slightly reduced chance of endometriosis in heavy smokers, who also had started smoking at a young age.

Francesca Bravi, together with collegues from different Italian universities, carried out a meta-analysis of published studies, to clarify the danger of endometriosis in smokers.  The study was published in the prestigious British Medical Journal(BMJ) in 2014.  A total of 1758 articles were reviewed, of which 38 met the inclusion criteria for this new analysis.  The new study included  13.129 women with endometriosis.  For study purposes,  the women were separated into groups of never smokers, smokers and those who had stopped smoking, as well as classifying them as light or heavy smokers.

It is well known that endometriosis is dependent on oestrogen, which is the female sexual hormone, regulating the menstrual cycle.

How can smoking affect the development of endometriosis?

The answer lies in the effect smoking has on the production of oestrogen as well as on inflammatory compounds.  Smoking reduces the production of oestrogen and progesterone and increases the secretion of inflammatory substances, not only in the lungs, but in all body tissues.  Both of which are mechanisms that influence the development and expansion of endometriosis.

 The present study did not prove any relationship between smoking and endometriosis.

 Conclusion: Smoking does neither stop nor cause the appearance of endometriosis.

F. Bravi et al.,BMJ Open 2014:4(12) e006325

Calhaz-Jorge C, Mol BW, Nunes J et al. Clinical predictive factors for endometriosis in a Portuguese infertile populationHum Reprod 2004;19:2126–31 doi:10.1093/humrep/deh374 [PubMed]

Aban M, Ertunc D, Tok EC et al. Modulating interaction of glutathione-S-transferase polymorphisms with smoking in endometriosisJ Reprod Med 2007;52:715–21. [PubMed]

Cramer DW, Wilson E, Stillman RJ et al. The relation of endometriosis to menstrual characteristics, smoking, and exerciseJAMA 1986;255:1904–8 doi:10.1001/jama.1986.03370140102032 [PubMed]
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