Endometriosis UK
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Having a colonoscopy to check for bowel endo while on my period....any advice on how to get through it?


I'm booked to have a colonoscopy to see how deeply into my bowel a lesion of endo goes (it showed up on an MRI) and the scan is booked for when I'm on my period. My gynaecologist said this is really good because then the endo will be really obvious, but my periods are already so horrific and painful and I'm scared about doing bowel prep and stuff while i am menstruating because I already struggle to cope with symptoms as it is!

Has anyone done this? Do you have any advice?

Thank you!

Hannah xxx

13 Replies

Hi - the sort of endo that infiltrates the bowel doesn't bleed so it won't necessarily be obvious. Deep nodules rarely infiltrate right through so it may well be clear. Others may be able to advise better about the pain but it would be sensible to take pain relief prior. If you are in thew UK I assume this is being done in a BSGE accredited specialist centre?


Hi Lindle thanks for replying.

I get rectal bleeding which is why they think there is a nodule in the bowel (and it came up on scans) do you have any links to stuff that explains that it doesn't bleed so i can discuss this with my surgeon?

I am seeing Peter Barton Smith who I think is BSGE accredited but I am not sure? I heard really good things about him though.

Thanks again!


Rectal bleeding can be a sign of endo affecting the bowel but it is usually due to inflammatory factors irritating the bowel and causing it to bleed. So if bleeding were to be found inside this could be caused by endo on the outside. When rarely endometriosis infiltrates the lumen this could cause bleeding too, but it is not endo bleeding. In that case a deep nodule should be visible.

The notion that endo follows the menstrual cycle and bleeds at period time with nowhere for the blood to escape has been repeated over the decades but there is no basis for it. The menstrual period is not caused by endometrial cells bleeding but by the breakdown of the functional layer of the endometrium. The endometrium has a rich blood supply but once progesterone is withdrawn prior to a period this causes restriction of the blood supply (ischemia) and as a result necrosis of the cells of the endometrium follows. The whole structure breaks down and dies; a mixture of released blood, mucosa and endometrial cells is then released as the period. So it is odd that this has been taken as endometrial cells bleeding when actually it is the cells dying. If we were to attribute that to endometriosis then each cycle the cells would die and be shed and endo would cease to be.

There is no evidence of endo 'bleeding' in this way and its pathogenesis is designed to enable it to survive. When it comes to the pathogenesis of deep endo, as is being considered in your case, this is described as 'that of dense fibrosis or fibromuscular metaplasia with relatively small areas of endometriosis which are poorly responsive to hormones.' If it were to bleed any blood would be hidden within the fibrous tissue and not reach the outside. If rectal bleeding is cyclical it is likely to be caused by inflammation from endo affecting the bowel; if it is with every bowel movement it may be more likely to suggest an infiltrating lesion through to the lumen.

Endo UK don't allow links to websites but the article below is by Jeremy Wright, the founder of the BSGE endocentre project, so presumably this would be allowed as they support the centres. They don't allow naming surgeons either, but the one mentioned is not in a BSGE centre. In order to operate on endo of the bowel, they have to work either in a BSGE accredited centre or one that follows their specification. So presumably he works in an independent centre that is monitored by the BSGE.

I hope this might have helped



The reason why Peter Barton-Smith isn't on the BSGE accredited list is because he only sees private patients & the BSGE centres are all NHS hospitals.


That's not the case. The BSGE list is for private and NHS centres.


If you look at the list the majority of hospitals are NHS.

Private consultants don't need to be accredited as they gain their own reputations via word of mouth.

There are even some excision surgeons who have decided not to join the BSGE list - and to carry on as before.

In order to become a centre you need a team. Most private consultants work alone & bring in colleagues as & when. They're not restricted by NHS rules or time constraints. If a surgery takes 5 hours then so be it.


You said the BSGE centres are all NHS hospitals - that is different from saying the majority are. The BSGE is not connected to the NHS, it is independent. There are more private centres evolving as can be seen from the provisional list.

Any excision surgeons operating on severe disease on the NHS as defined by the NHS England service contract (E10/S/a) who are not working out of centres applying the BSGE criteria are breaking the terms of both the contract and the 2016 RCOG Standards for Gynaecology Care, which they are bound by their RCOG registration to apply.

With regard to private care, surgeons must apply the same standards as laid out in national guidelines, as would apply in the NHS. The CQC confirms that in assessing independent hospitals the following must be applied:

1. How are relevant and current evidence-based guidance, standards, best practice and legislation identified and used to develop how services, care and treatment are delivered? (This includes from NICE and other expert and professional bodies).

2. Do people have their needs assessed and their care planned and delivered in line with evidence-based, guidance, standards and best practice? How is this monitored to ensure compliance?

Clearly we would not be happy to be treated by private surgeons failing to apply evidence-based standards?


I have had this and also had to use bowel prep on 3 separate occasions. First of all I would ring them and explain that it coincides with your period and see if they can give you a different appointment. If they can't and you decide to go ahead, the bowel prep really isn't that bad (I have always been given moviprep). Do 3 days of low residue diet before the prep day (white bread, ice cream, white rice, no fruit/veg/fibre) and use laxatives on those days if you need to, to make sure you keep going to the loo. On the prep day you will need to be close to a toilet once you start drinking the prep. It usually takes an hour or so to start working. Expect to feel very tired and washed out the next day. The colonoscopy itself isn't pleasant, but is usually quite quick and you can ask to be sedated if you're worried about pain. I wasn't and it was for the most part OK, there were just a few difficult moments when the scope goes round the corners. My colonoscopy was clear even though I had extensive bowel and rectovaginal endo.


Gosh you poor thing having it three times! You must be an expert now though so I will take your advice hahaha!

They actually relaly want me to have it when I am on my period because it will make it easier for them to spot the endo apparently so I don't think I can change it.

I've never heard of a low residue diet before so I will look into that thank you!


Hi I had a colonoscopy 2 years ago and the only thing they found was a polyp. I have to have one every three years now. I have severe endo on the bowl and it has penetrated the bowl wall. They only found that on a MRI scan . Have they offered you one ?? .

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Have to say that I negotiated a general anaesthetic for mine as I was emotionally unable to deal with having one due to past trauma. I am extremely glad I did so and that my surgeon was honest and said some women do find them painful and sometimes if you are very anxious the sedative isn't entirely effective. Might be worth discussing this possibility.

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Hi Hannah

I had a colonoscopy last year and i started my menstraul cycle the morning of the procedure i was very anxious when i arrived as i was already in pain from my period but honesty it wasnt that bad they gave me some pain relief before the procedure and instead of using gas to do the procedure they used water as i had previously had a sigmonoscopy with gas and found it very painful. Using the water was so much better! It is uncomfortable when they go round the corners but not unbearable and it is a fairly quick procedure. Hope it all goes well for you.

Annie x

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Hi Hannah,

I am 26 and have had 3 colonoscopies, also during the time of the month and I have extremely heavy periods where I bleed on end for weeks, honestly don't worry about the bleeding, they were so good with me, I told them as soon as I arrived and they basically said it's nothing they haven't seen before, they placed like a mat type thing beneath me and you are turned on your side for part of it so I really wouldn't panic, they specialise in this so they are used to things like this, I had four polyps removed also.... with regards to the movi prep I was given to take the day before to clear my bowels, it isn't the most pleasant drink however I was told to add a little squash to it but not blackcurrent or anything as that can stain the bowel so I used lime juice, I also found on my last dose of movi prep I was still going to the toilet the morning of the procedure but again don't be embarrassed by that it may only be a little bit but they basically suck it out...

Sorry for the detail hope all goes well for you,

Chloe x

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