A 30-year-old woman wishes to have the levonorgestrel intrauterine system
(Mirena) for contraception.
(a) Discuss the unwanted side-effects of this method of contraception. (8 marks)
(b) What are the additional benefits of Mirena? (5 marks)
(c) What advice will you give her after inserting the device? (7 mar
Common mistakes
● Discussing how Mirena works
● The pros and cons of Mirena
● Discussing data on its efficacy in menorrhagia
● Cost of Mirena compared to other forms of contraception
● Expulsion rates and continuation rates of Mirena
● Discussing the treatment of irregular bleeding
A good answer will include some or all of these points
(a) Discuss the unwanted side-effects of this method of contraception. (8 marks)
● Irregular vaginal bleeding worse over the first 3–4 months
● Localised uterine pain
● Acne, oily skin, fluid retention
● Breast tenderness
● Depression
● Weight gain
● Functional ovarian cysts (10–15 per cent of cases)
(b) What are the additional benefits of Mirena? (5 marks)
● Menorrhagia – treatment may result in amenorrhoea or hypomenorrhoea
● Dysmenorrhoea
● Fibroids
● Adenomyosis – reduces the size of the adenomyosis
● Endometriosis
● PMS – whether this is the placebo effect is uncertain
(c) What advice will you give her after inserting the device? (7 marks)
● Irregular periods/bleeding – worse over the first 3–6 months
● Most likely to settle into amenorrhoea or hypomenorrhoea or oligoamenorrhoea
● Feel string after each period
● Counsel about side-effects
● If planning on a pregnancy, report for removal, otherwise give date for removal (after 5 years)
● Avoid multiple sexual partners – although may decrease the risk of pelvic inflammatory
disease (PID)
● If pregnant, need to exclude an ectopic pregnancy
Sample answer
(a) Discuss the unwanted side-effects of this method of contraception. (8 marks)
The levonorgestrel intrauterine system delivers the progestogen levonorgestrel at a steady rate
of 20 μg/day for 5 years. Although this is mainly into the uterine cavity, some of it is absorbed
and causes systemic progestogenic side-effects.
However, most of the severe side-effects of
Mirena are related to the local effects of the progestogens.
The most common unwanted side-effect is irregular vaginal bleeding. This is unpredictable
and is worse over the first 3–4 months.
For most women, this is the reason for discontinuation.
The systemic side-effects include acne, oily skin, fluid retention (manifesting as weight gain,
depression and breast tenderness).
The Mirena® is associated with functional ovarian cysts which may present with localised abdominal pain. These cysts occur in approximately 10–15 per cent of cases.
Most of them are asymptomatic and do not require treatment. Although
rare, some women complain of localised discomfort over the uterus; this is related to the positioning of the Mirena.
(b) What are the additional benefits of Mirena? (5 marks)
Mirena has several non-contraceptive benefits. It is very effective in the treatment of menorrhagia where it has been reported to reduce bleeding by approximately 70–80 per cent in
approximately 70 per cent of patients who are placed on the device.
It is now a recommended method of treatment for menorrhagia, especially the idiopathic type.
It is effective in other gynaecological conditions, e.g. endometriosis, adenomyosis and
fibroids. In women with minimal to moderate endometriosis, it has been shown to be effective
with a reduction in pain reported in 70 per cent of patients after 3 years.
Although a small cohort of women with adenomyosis has been shown to benefit from Mirena ,there are no large studies to confirm this. It has been reported to be beneficial in those with fibroids and
PMS. Whether it is the placebo effect in the PMS group is uncertain. What is clear is the fact
that it may make the symptoms of PMS worse.
(c) What advice will you give her after inserting the device? (7 marks)
The most important advice to be offered to anyone after insertion of the Mirena is with
regards to irregular vaginal bleeding. This bleeding is unpredictable and could be heavy in
some cases. However, it does get better and for most women this tends to be replaced by
hypomenorrhoea.
Since irregular bleeding is the most common reason for discontinuation,
anticipatory counselling will result in better compliance. Several approaches have been tried to reduce this but the most appropriate is counselling.
The device is best inserted during menstruation as it guarantees that the patient is not pregnant. In addition, the insertion is easier. Following insertion, the woman must be advised to feel for the strings of the device especially after the first few periods if they are heavy. If she is planning another pregnancy, the device should be removed. otherwise a date for removal should be given and documented in her notes (usually 5 years from the date of insertion) and the card given to her. Multiple sexual partners should be avoided and she should report early
whenever she becomes pregnant to ensure that an ectopic pregnancy is excluded
About the Author
