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This is a plain English summary of an original research article. The views expressed are those of the author(s) and reviewer(s) at the time of publication.

This NIHR-funded trial compared treatment of uterine polyps under local anaesthetic at the time of diagnosis in a hospital outpatient clinic with inpatient treatment under general anaesthetic on another day. Treatment success, as determined by women’s assessment of bleeding, was no worse in the clinic treated group, using a pre-determined threshold for an important difference. In the outpatient group failure to remove a polyp was more likely, the procedure was slightly less acceptable to women and was slightly more painful. Inpatient treatment with general anaesthetic was more expensive, as expected. Nonetheless, some women may prefer the convenience of same day outpatient treatment so should be informed of the risks and benefits of both options.

Why was this study needed?

Abnormal bleeding from the womb is the most common reason for a visit to hospital gynaecology departments. Around 20-40% of women with abnormal bleeding have non-cancerous bulges in the lining of the womb, called uterine polyps.

Polyps are usually diagnosed in a hospital outpatient clinic; a booking is then made for a separate visit to hospital for surgery to remove them under general anaesthetic, usually as a day patient. Removal in the outpatient clinic under local anaesthetic at the time of diagnosis is also an option; this reduces the number of hospital visits which might be more convenient for women and it may save the NHS money. The NIHR funded this trial, called OPT, to discover whether outpatient treatment was as effective and acceptable to women as inpatient treatment. A related study compared the costs of the two approaches.

What did this study do?

This was a large randomised controlled trial comparing usual inpatient treatment to remove polyps under general anaesthesia, with outpatient treatment close to the time of diagnosis. Some women randomised to outpatient treatment came back at another time so that 72% of women in this group were treated in a “see and treat” clinic on the same day.

The main outcome was treatment success as determined by women’s self-assessment of bleeding improvement by six months after surgery. For women with bleeding after the menopause or between periods, this meant bleeding stopping completely. For women with heavy periods, success was a reduction in bleeding to acceptable levels. Women were asked how acceptable they thought the procedure was one week after having it, and how much pain they experienced by the time they left the hospital. The researchers also recorded failure rate for removing polyps.

The trial randomised 507 women with confirmed polyps, treated at 31 NHS hospitals, so results should be applicable to the NHS in general.

What did it find?

  • Slightly fewer women reported successful improvement in bleeding six months after outpatient treatment (73%) compared with inpatient treatment (80%), but this difference was not statistically significant (relative risk 0.92, 95% confidence interval 0.82 to 1.02).
  • Average pain levels on leaving hospital were slightly worse for outpatient treatment: 23 out of 100 compared with 17 out of 100 for inpatients, where 100 is the worst pain (p <0.001).
  • Failure to remove the polyp was more common with outpatient treatment (19% of women) than inpatient treatment (7%). Discomfort was the main reason.
  • Overall, slightly fewer women in the outpatient group would recommend the procedure to a friend. But some women thought the extra discomfort of treatment under local anaesthetic rather than general anaesthetic was worth it because of the added convenience of being treated as an outpatient.
  • Outpatient treatment was cheaper than inpatient treatment: a year after treatment, for every extra successfully treated person in the inpatient group, the cost would be £22,293 more than outpatient treatment. From a National Health Service perspective at one year this would cost £445,867 extra for each additional year of good quality life (QALY). Outpatient treatment thus has a high chance of being very good value for money at the threshold of treatments usually funded in the NHS.

What does current guidance say on this issue?

There is no guidance focussing on removing uterine polyps. Guidelines from the Royal College of Obstetricians and Gynaecologists in 2011 on hysteroscopy, the procedure to examine inside the womb, includes a general recommendation for outpatient treatments such as polyp removal. These recommendations include appropriate operating facilities and adequately skilled staff.

What are the implications?

The study included over 500 women from over 30 NHS hospitals so is likely to give good representation of the various types of abnormal bleeding associated with uterine polyps.

It suggests that having a single, clinic appointment to diagnose and remove uterine polyps can work just as well as having a separate hospital admission to remove polyps under general anaesthetic. The outpatient procedure was slightly less acceptable overall but for some women, the convenience of attending hospital once rather than twice outweighed any downsides.

The difference in costs between the two strategies is substantial: the linked economic evaluation suggests outpatient treatment at the time of diagnosis gives value for money.


Cooper NA, Clark TJ, Middleton L, et al. Outpatient versus inpatient uterine polyp treatment for abnormal uterine bleeding: randomised controlled non-inferiority study. BMJ. 2015;350:h1398.

This project was funded by the National Institute for Health Research Health Technology Assessment Programme (project number 06/404/84).


Diwakar L, Roberts T, Cooper N, et al. An economic evaluation of outpatient versus inpatient polyp treatment for abnormal uterine bleeding. BJOG: An International Journal of Obstetrics & Gynaecology. 2015.

NHS Choices. Hysteroscopy. Leeds: NHS Choices; 2014.

NHS Choices. Post-menopausal bleeding. Leeds: NHS Choices; 2014.

RCOG. Hysteroscopy, best practice in outpatient (Green-top Guideline No. 59). London: Royal College of Obstetricians and Gynaecologists; 2011.

Produced by the University of Southampton and Bazian on behalf of NIHR through the NIHR Dissemination Centre

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Newer smaller diameter instruments can be used with local anaesthesia to look inside the womb in an outpatient setting. Treatment of polyps can be done at the same time as diagnosis using the “see and treat” principle. The alternative is traditional dilatation and curettage for diagnosis and treatment with general or regional anaesthesia in an operating theatre, usually as a hospital day patient.

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