There have been a few studies published of late concerning what other conditions endometriosis is associated with.
First up is a study from Brazil which looked at the frequency of celiac disease in women with and without endometriosis. Just to give you a brief overview, celiac disease is a digestive disorder that leads to poor absorption of nutrients through the gut due to damage of the small intestine. Celiac disease can result in people not being able to tolerate things like gluten and presents with a variety of symptoms (For more information on celiac disease follow this link). The study found that 0.66% of women without endometriosis had celiac disease, whereas 2.5% of women with endometriosis had celiac disease. So although the numbers were relatively small women with endometriosis were more likely to have celiac disease. This is interesting because, from my experience, a lot of women with endometriosis also have food allergies or intolerances.
Next is a study from Australia that looked at the frequency of pre-eclampsia in women with endometriosis. Pre-eclampsia is a condition whereby during pregnancy a woman suffers from hypertension. This can be a very serious problem if left untreated for both the mother and child. However, the overall result of this study was that there is no increased chance of suffering from pre-eclampsia if you have endometriosis. In fact there is some evidence to suggest that if you have endometriosis you are less likely to suffer from pre-eclampsia, which is good news, for a change.