Members Enquiry Service

The Clinical Effectiveness Unit (CEU) provides an evidence-based enquiry service for FSRH members. The CEU will conduct a literature review and summarise the available evidence in relation to a particular medical condition and/or contraceptive method.

Recent Questions and Answers that have been submitted to the CEU can be seen below. Please note, the full answer includes references to more information and guidance.


To gain access to the enquiries service, please log in to ‘My FSRH’ and click on ‘My Clinical Enquiries’ to search for questions or submit your own question. This service is available to current FSRH members. If you are an FSRH member and have not yet created your ‘My FSRH’ account, please click the ‘Register’ button on the top right of this website and follow the steps to gain access to your account.

Example Question One

My patient is 53 years old and has a history of breast cancer (fully excised, recent normal mammogram, now in year 4/5 of tamoxifen). She had a mirena fitted in 7 years ago in 2010 (at age 46) and not had any bleeding for several years. FSH in January this year was 28 and it has been in the high 20s for the last few years. We are trying to work out when it would be safe for her to remove her mirena. I understand that is amenorrheic a mirena fitted over 45yo can be a woman's last. I would usually wait until 56 to remove it or do so a year following serial FSH readings >30. My question is this: Does the tamoxifen have an impact on her FSH result, and therefore can I rely on this method in giving her advice about her contraceptive need?

Tamoxifen is an estrogen receptor modulator that can stimulate production of gonadotrophins, including follicle stimulating hormones (FSH).[1,2] The CEU advises therefore that serum FSH is not a reliable indicator of menopausal status in a woman who is using tamoxifen.

Insertion of Mirena® is UKMEC3 for a woman with past breast cancer [3] because of the theoretical risk of the hormone levonorgestrel released from the IUS being associated with cancer recurrence. However, any small increase in breast cancer risk that might be related to the low levels of levonorgestrel released from the Mirena after 7 years must be weighed carefully against the fact that (1) the Mirena is still providing effective contraception and (2) for the first 5 years after insertion, Mirena protected the endometrium from the stimulatory effects of tamoxifen. After seven years of use, it is unknown whether Mirena has any ongoing protective effect on the endometrium. However any ongoing levonorgestrel release would be likely to be beneficial for the endometrium.

The CEU suggests that after discussion regarding potential risks and benefits, the woman could make an informed decision to keep the existing Mirena until after the age of 55 years when she no longer requires contraception. Alternatively, if the Mirena was removed, she could use a barrier method or copper IUD until the age of 55 years.

Example Question Two

I have a 47 year old patient who has had a Mirena since 2010 (changed in 2015). She has been diagnosed with haemachromatosis and is needing bi weekly venesection. It has been suggested to her by her haematologist that it may help her condition to have periods and that the Mirena should maybe be removed. (although it has been left up to her to decide!) She is happy with the Mirena and is not sure what to do. Is there any evidence that removing it to allow periods to occur will reduce the amount of venesection she is needing? 


The CEU conducted a literature search and found no evidence as to whether menstrual bleeding has a significant beneficial impact for women with haemochromatosis. We therefore cannot make a recommendation on whether removing a woman’s Mirena® will reduce the requirement for venesection.

Women lose, on average, 30-40 ml of blood during each period. The 10% of women who experience heavy menstrual bleeding lose >60 ml each cycle.[1] Venesection removes around 500ml of blood during each session.-2 If a woman requires 1 litre of blood to be removed each week, the blood lost during her monthly cycle may not make a significant difference. Any potential benefit would also have to be weighed against the inconvenience to the woman if menstrual bleeding after IUS removal was heavy and/or painful and the requirement for alternative effective contraception.

Example Question Three

Can an 18 year old who's father is on warfarin for recurrent DVTs with hereditary spherocytosis have the combined pill? She hasn't been tested for HS.

Hereditary spherocytosis (HS) is a condition that makes the surface membrane of red blood cells less stable. These red blood cells can lose some of their membrane when passing through the spleen and therefore become spherical. Spherocytic red blood cells are destroyed much more quickly than regular ones, potentially causing anaemia and high bilirubin levels leading to jaundice and gallstones.[1] Splenectomy is often performed in order to prevent the red blood cells from becoming damaged.[2]

HS shows autosomal dominant inheritance in about 75% of cases and 20-30% of individuals with HS have a mild form of the condition that may present with no symptoms.[3] Therefore, the daughter of an affected individual has a significant risk of having HS but may be asymptomatic.

There is currently no available evidence that evaluates contraception use in individuals with HS. However, there is evidence of increased blood viscosity and an increased risk of thrombosis and other arterial events after splenectomy.-6

As there is no evidence relating directly to use of combined hormonal contraception (CHC) by women who have HS but have not undergone splenectomy, we cannot make a recommendation for this woman based on a literature review. After splenectomy for HS, the CEU would recommend that CHC is best avoided because of the potential increased risk of thrombosis. The CEU reminds clinicians that oral contraceptives have a 9% failure rate with typical use and that long acting reversible methods of contraception (LARC) have a much lower failure rate.


Please note: The advice given by the CEU should be considered as guidance only and is meant to be used alongside clinical judgement to guide clinical practice or policy. Questions that are a matter of clinical judgment and not evidence should be directed to local sexual and reproductive health leads.