The Pill

by Ros Wood

The combined oral contraceptive pill has been used for women with endometriosis since the late 1950s, and for many years it was the main hormonal drug used [1].

The combined oral contraceptive pill is not just one drug. Rather, there are many different types, each of which contains a specific low-dose combination of synthetic oestrogen and progestagen (progesterone).

The main advantages of the pill are that it is inexpensive and is usually reasonably well tolerated by women [2]. It can also be taken safely for many years if necessary, unlike most of the other hormonal drug treatments for endometriosis [2].

How it works

Like all the other hormonal treatments, the pill does not cure endometriosis. Rather, it alleviates the pain of endometriosis by suppressing menstruation and inhibiting the growth of the endometrial implants.

Because everyone responds differently to different dosages of hormones, it is some times necessary to “experiment” until one finds the pill that works best, and has the least side effects.


Depending on your symptoms, some gynaecologists recommend that the pill be taken daily for blocks of 3 Weeks, followed by a break of 1 week, during which time you will have a light period. This is the way the pill is taken when used as a contraceptive.

However, with endometriosis-associated pain, some gynaecologists recommend that the pill be taken daily continuously; or daily for blocks of 3–4 months, followed by a break of 1 week, during which time you will have a light period.

Taken in any of these ways, you can safely use the pill for many years [2].

Theoretically, taking the pill continuously or for blocks of 3–4 months should be more effective in suppressing endometriosis than taking it for blocks of 3 weeks, because it results in fewer menstrual periods. However, little research has been done to support this hunch. In one study involving women whose symptoms had not been alleviated with cyclic (3 week blocks) use of the oral contraceptive pill, 80% of the women were satisfied or very satisfied with the results of taking the pill continuously [3].

Effectiveness for pain symptoms

Very few studies have looked at the effectiveness of the combined oral contraceptive pill in treating the pain-related symptoms of endometriosis. Nevertheless, the existing evidence suggests that its effectiveness in alleviating pain is similar to the other hormonal drugs during treatment, and there is no difference 6 months after stopping taking the pill [2].

Effectiveness for infertility

The combined oral contraceptive pill — like all the hormonal treatments used for endometriosis — will not improve your chance of conceiving, so it should not be used as a treatment for infertility [4].

Keeping track

You should visit your gynaecologist about 6–8 weeks after starting the pill to discuss how the treatment is progressing, and after that every 6 – 8 monts. However, do not hesitate to contact your gynaecologist if you develop any problems between scheduled visits.

Pregnancy and breastfeeding

There is no conclusive evidence to suggest that taking the pill during pregnancy will endanger the developing foetus. However, you should not to take the pill if there is any possibility that you may be pregnant [5].

Small amounts of the hormones that make up the pill can be passed into breast milk. Therefore, you should not use the pill while breastfeeding [5].

The pill interacts with some medicines, so do tell your gynaecologist if you are taking any other medicines or supplements, including any you have bought from a pharmacy, health food shop or a supermarket.

Side effects

You may experience some side effects when using the pill. The more common ones include irregular vaginal bleeding, fluid retention, abdominal bloating, weight gain, increased appetite, nausea, headaches, breast tenderness and depression.

Nausea and breast tenderness usually settle after 1–2 months of treatment. The remaining side effects usually disappear within a few weeks after you stop taking the pill, and you will usually start ovulating and menstruating again within 4–6 weeks of taking the last tablet.

  1. Kistner RW. Conservative management of endometriosis. Lancet 1959;79(5):179-83
  2. Kennedy S. The Patient’s Essential Guide to Endometriosis. England: Alden Press, 2004: 54.
  3. Vercellini P, Frontino G, De Giorgi O et al. Continuous use of an oral contraceptive for endometriosis-associated recurrent dysmenorrhea that does not respond to a cyclic pill regimen. Fertil Steril. 2003;80(3):560-3.
  4. Kennedy S, Bergqvist A, Chapron C, D’Hooghe T, Dunselman G, Greb R, Hummelshoj L, Prentice A, Saridogan E. ESHRE guideline for the diagnosis and management of endometriosis. Human Reprod 2005;20(10):2698-2704.
  5. Royal Women’s Hospital’s Drugs in Pregnancy and Breastfeeding Handbook.
Thank you to the following for reviewing this article prior to its publication

Andrew Prentice, Senior Lecturer and Consultant Gynaecologist, Cambridge University, United Kingdom
Paolo Vercellini, Associate Professor, University of Milano, Italy

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