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.
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 %.
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.