Mirena or Jaydess?

2017, Responses from: Mr Michael East

I am 20 years old, have a diagnosis of endometriosis and have not had children. My gynecologist has suggested a Jaydess be placed at my next laparoscopy. Why a Jaydess and not a Mirena? I am confused. I have not had one of these

Mr Michael East: Hi everyone, as a clinician who inserts a lot of Mirena intra uterine devices, I would like to share with you how it can help many women and also to point out how to recognise if it is not suiting you. Usually in my experience it is generally part of the solution and not part of the problem.

Firstly, let us consider what a Mirena consists of:

It is ‘T-shaped’ plastic (nylon) device that has a slow release hormone capsule attached to the ‘stalk’ of the T. It acts as a very efficient contraceptive and has a 5-year lifespan.  What are its properties? The ‘T’ serves to hold the hormone capsule inside the cavity of the uterus. It is chemically inert but as a foreign body it can act as an irritant to the uterus causing the uterine muscle to contract and cramp more often. This is more likely to occur in teenagers as the uterus is smaller and the ‘fit’ a little tighter. For younger women, the smaller Jaydess may be a better choice.

The hormone is a copy of the female hormone progesterone, and has two main actions:

  1. It causes relaxation of the uterine muscle (called smooth muscle) and as such, tends to decrease the irritant effect of the plastic ‘T’.
  2. It inhibits the growth of the uterine lining (endometrium) and any similar tissue (endometriosis and adenomyosis). This inhibition tends to reduce pain.

Generally, the hormone effect tends to dominate over the foreign body effect, and if that is so, then a Mirena tends to produce benefit to the user. If the foreign body effect is dominant, then cramps and bleeding can aggravate endometriosis symptoms.

The amount of hormone that leaks into the rest of a woman’s body is equivalent to taking one progesterone only contraceptive pill per week. As a result, most women do not experience hormone related side effects. Some women however are sensitive to this small hormone leak and experience a deterioration of acne or a flatness of mood. Some women find that their cyclical mood swings get worse, while others notice no difference or improvement.

Who do I advise to have a Mirena placed?

Most women undergoing surgery for endometriosis in my experience, benefit from having a Mirena placed at the time of surgery while they are asleep. They should be warned that it takes at least three months to ‘settle in’ and breakthrough bleeding can be an issue during this time, along with cramping. In other words, they need to ‘cut it some slack’ during that time. It tends to eventually add to the effectiveness of surgery and there is growing evidence that it decreases the number of women needing repeat operations for recurrent endo symptoms.

Who do I advise to avoid a Mirena?

Obviously if you are trying to become pregnant it is a no brainer. The main group of women that I suggest do not to have a Mirena are those who have a diagnosis of ‘polycystic ovary syndrome’ (PCOS), as it tends to aggravate acne or abnormal body and facial hair growth.


This is made by the same company that makes the Mirena and is smaller in ALL dimensions. It is basically a ‘honey I’ve shrunk the Mirena’ option and lasts for 3 years. It’s smaller in size means that it is less likely to cause painful cramps in younger women with a smaller uterus and it better fits inside a smaller uterine cavity.

Otherwise it does the same job as a Mirena.

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