Printed on: May 10th, 2025

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Contraception following a diagnosis of breast cancer

Contraception following a diagnosis of breast cancer

This article was written in February 2025.

Breast cancer is the commonest cancer in women of reproductive age, accounting for around 43% of all cancers in women aged 25-49y. Early diagnosis and development of effective treatments mean that increasing numbers of women survive breast cancer and continue to lead normal lives. Although some cancer treatments have a negative effect on sexual function and fertility, many women continue to be sexually active, and therefore may remain at risk of pregnancy.  

Because pregnancy should be avoided in women with a history of, or undergoing, treatment for breast cancer, it is important to provide accurate and appropriate advice about effective contraception. Contraceptive options are limited because hormonal preparations are generally contraindicated due to the hormone sensitivity of some breast cancer, and therefore the potential risk of recurrent disease.   

This article summarises FSRH guidance on supporting contraceptive choices for individuals who have or have had breast cancer (fsrh-cadbc-guidance-document-15-nov-2023.pdf).

For further information on this area, see our articles:

• Hormonal contraception: risk of cancer.
• Managing menopause after a diagnosis of breast cancer.  

Pregnancy should generally be avoided during, and for some time after, breast cancer treatment. This is because:

• The hormonal state of pregnancy may affect disease progression in the short term (General and Comparative Endocrinology 2024;352:114501).
• Treatments are teratogenic or may have unknown effects on a developing foetus. 
• Treatment would need to be stopped or delayed during the pregnancy, potentially impacting efficacy and disease outcome.

The FSRH:

• Does NOT consider tamoxifen, aromatase inhibitors or GnRH analogues as reliable contraception.  
• Advises that women <50y who have been amenorrhoeic during or following medical treatment for breast cancer (including chemotherapy, which can cause ovarian insufficiency during treatment) may regain some ovarian activity and ovulate – irrespective of FSH levels.

It therefore advises that, following a diagnosis of breast cancer, all sexually active women should use effective contraception unless they meet any of the criteria below.

FSRH guidance states that a sexually active woman does NOT need contraception if she:

• Is ≥55y.
• Is ≥50y AND has been NATURALLY amenorrhoeic for >1y (i.e. not on any hormonal, drug or radiation treatment).
• Has had an FSH level >30 IU/L taken >1y ago, AND when she was ≥50y AND before starting chemotherapy/hormone breast cancer therapy.
• Is aged 40–50y, has NOT taken any medical treatment for breast cancer AND has been naturally amenorrhoeic for >2y (Aged Over 40 | FSRH).  
• Has had surgical treatment which would prevent pregnancy, e.g. sterilisation (or partner has been sterilised), bilateral oophorectomy or hysterectomy.

There is limited evidence looking at the risks associated with hormonal contraception use in women with a history of breast cancer. However, because breast cancer can be a hormone-sensitive disease, the FSRH takes a precautionary approach in its recommendations.

The table below lists current UK medical eligibility criteria (UKMEC) categories for the different contraceptive methods.

(Note: 1 = no restriction to use, 2 = benefits usually outweigh risks, 3= risks usually outweigh benefits, 4 = absolute contraindication).   

The FSRH recommends highly-effective non-hormonal contraception first line (ESPECIALLY for women taking teratogenic medication), specifically:

• The copper IUD.
• Female or male sterilisation.

These are around 99% effective.

• Hormonal methods should generally be avoided.
• Barrier methods (condoms, diaphragms and caps + spermicide) and fertility awareness methods (including contraception apps) are medically safe, but less effective than the IUD and sterilisation.
• Fertility awareness methods which rely on menstrual cycles may be impacted by breast cancer treatments which can cause menstrual irregularities.   

• Women who are on hormonal contraception at the time of breast cancer diagnosis should stop their method as soon as possible and switch to a non-hormonal alternative.
• If stopping contraception puts a woman at risk of unintended pregnancy, discontinuation may be delayed until the risk has passed or until specialist advice has been sought. However, CHC users should switch to an interim progestogen-only method.    

A healthcare professional may consider offering a progestogen-only method of contraception on an individual basis if other methods are unacceptable or inappropriate, or if there are additional gynaecological benefits from it. For example, women who:

• Would not be able to tolerate an IUD fitting or develop painful heavy periods with the method.  
• Are at increased operative risk or want to avoid a medical procedure such as sterilisation.
• Have gynaecological conditions (e.g. dysmenorrhoea, heavy menstrual bleeding, endometriosis).

This should be a patient-centred decision which includes consideration of the type and grade of tumour, as well as treatment given, and should involve a contraception specialist and breast cancer specialist.  

There is limited evidence to indicate which progestogen-only method is likely to be safest. FSRH guidance therefore extrapolates from observational general population data, which suggests that all progestogen-only methods may increase the risk of breast cancer slightly.

When discussing the best option with a patient, we should consider:  

• Medical history and patient characteristics (e.g. age, weight) that may impact medical eligibility.
• Drug interactions that may impact the efficacy of oral and subdermal progestogenic contraception.
• The importance of a highly-effective method if a patient is on a teratogen.

It would seem to make sense that a low-dose preparation like the IUS should be safer than higher-dose progestogenic methods. Moreover, for women on tamoxifen who may be at increased risk of endometrial cancer, an IUS would potentially reduce endometrial risk. However:

• There is no evidence to support the safety of the IUS over other methods.
• A number of studies have looked at IUS use in women with a history of breast cancer, but they were all too small to reach definitive conclusions regarding breast cancer outcomes.
• A Cochrane review found that the IUS reduced the risk of endometrial cancer in women on tamoxifen, but the IUS is not currently licensed to be used in this scenario.  

Combined hormonal contraception should be avoided after any breast cancer due to the potential increased risk of thrombosis as well as breast cancer.

• There is a large body of observational data from general population studies which suggests that CHC is associated with a slight increased risk of breast cancer while taking the method and for up to 10y after stopping.
• Studies looking at HRT use in menopausal women show increased risk of breast cancer in combined HRT users, which may be extrapolated as evidence of harm from exogenous hormones.   
• Breast cancer and its treatment is associated with increased risk of VTE, as is CHC use. FSRH guidelines therefore recommend that women with a history of breast cancer avoid CHC.  
• Women on a breast cancer treatment which works by suppressing endogenous oestrogen production (e.g. an aromatase inhibitor) should not take CHC because this would negate the therapeutic effect.

The FSRH states:

• The copper IUD should be first-line emergency contraception due to its efficacy and non-hormonal nature.
• If an IUD is not appropriate, either ulipristal acetate or levonorgestrel oral emergency contraception may be given (see article on Emergency contraception for more information).

There is no evidence looking at the safety of emergency contraception in women with a history of breast cancer, but the FSRH regards a one-off dose of an oral hormonal emergency contraception as unlikely to be harmful, and any potential risks likely to be outweighed by the benefit of unplanned pregnancy prevention.  

Contraception following a diagnosis of breast cancer Breast cancer is the commonest cancer in women of reproductive age, and pregnancy should generally be avoided during, and for some time after, breast cancer treatment. Medical treatments for breast cancer may cause amenorrhoea, but do not provide contraception, nor mean that a woman is no longer fertile. The FSRH recommends a copper IUD or sterilisation as first-line contraception methods in women with a history of breast cancer. Hormonal contraception should generally be avoided unless there are compelling reasons to use it, but combined hormonal contraception should not be used. There are no restrictions on emergency contraception use in women with a history of breast cancer.