Contraception in the Female Athlete

The choice of method starts with an assessment of medical suitability using the UK Medical Eligibility Criteria (UKMEC), considering the possibility of pregnancy, blood pressure, migraine with aura, venous thromboembolism risk, smoking, liver disease, a history of breast cancer, and drug interactions; it is also worth remembering that contraception does not protect against sexually transmitted infections, so condom advice remains relevant. Combined hormonal contraception, as the combined oral contraceptive (COC), patch or ring, contains oestrogen and a progestogen, allows the timing of bleeds to be controlled, can help heavy menstrual bleeding and period pain, and in adult women generally has little effect on bone mineral density, with some concern about adolescents. The progestogen-only pill (POP) contains no oestrogen and can cause unpredictable bleeding.

Long-acting reversible methods differ in their bleeding effects, which matters to athletes. The levonorgestrel intrauterine system (LNG-IUS) commonly reduces bleeding, whereas the etonogestrel implant commonly causes unpredictable bleeding and does not reliably reduce heavy menstrual bleeding, and the non-hormonal copper intrauterine device may increase bleeding. Depot medroxyprogesterone acetate (DMPA), the injectable progestogen, is effective and is associated with a small reduction in bone mineral density that is usually recovered after discontinuation, along with variable effects on weight, since some users gain weight but individual response varies. It can be used, including under the age of eighteen, after considering alternatives and with regular review, commonly every two years, so it is considered carefully rather than being automatically unsuitable for every athlete with a bone concern. The choice is individualised to what matters most to the athlete alongside her medical eligibility.

Athletes often ask whether hormonal contraception will help or hinder performance. The honest answer is that the current evidence does not show a clear, consistent effect on performance, and manipulation of the cycle to try to improve strength is not justified by the evidence, so the method is chosen for health, medical eligibility, contraceptive need and personal preference rather than as a performance aid. What contraception can offer is control of bleeding. Continuous or extended use of combined hormonal contraception can suppress a withdrawal bleed around a key competition. Norethisterone can delay a period, but it is not a contraceptive, must be started several days in advance, and requires assessment for contraindications.

There is also a benefit for iron, with an important qualification. Reducing menstrual blood loss lowers iron loss and helps prevent or treat iron-deficiency anaemia, with ferritin used to monitor iron status, but this benefit applies to methods that actually reduce bleeding, especially the levonorgestrel intrauterine system and suitable combined hormonal contraception. The etonogestrel implant and the progestogen-only pill can cause unpredictable bleeding and do not reliably reduce it. So while contraception is not an ergogenic aid, a method that suits the athlete and reduces heavy bleeding can support training and wellbeing through predictable bleeding, symptom control and reduced iron loss, which is a reasonable and evidence-based reason to consider it alongside its contraceptive purpose.

The most important consideration specific to athletes is the interaction with relative energy deficiency in sport (RED-S). Hormonal contraception produces regular withdrawal bleeds or reduces bleeding, so it obscures the spontaneous menstrual cycle and can hide amenorrhoea. Amenorrhoea, however, is only one indicator of RED-S, so monitoring should not rely on periods alone and should also include energy intake, performance, bone stress injury, mood, endocrine symptoms and other health markers. If an athlete starts hormonal contraception, the clinician and athlete agree in advance how RED-S risk will be monitored.

This has a direct bearing on bone. Where the periods have stopped because of low energy availability, the priority is restoring energy availability, because that addresses the underlying cause. Transdermal 17-beta-oestradiol given with cyclical progesterone is not contraception; it is an off-label, specialist-led treatment for selected athletes with persistent functional hypothalamic amenorrhoea and impaired bone health after adequate nutritional and training intervention, and it is not offered automatically whenever more bone protection is wanted. Bone health is assessed with dual-energy X-ray absorptiometry where indicated. Finally, no contraceptive method is currently prohibited in sport, but the decision does not rest on preference alone: medical eligibility, effectiveness, bleeding effects and drug interactions remain central, discussed openly with the athlete.

• •Start with an assessment of medical suitability using the UK Medical Eligibility Criteria, and remember that no contraceptive method protects against sexually transmitted infections.
• •Bleeding effects differ: the levonorgestrel intrauterine system commonly reduces bleeding, the implant and progestogen-only pill can cause unpredictable bleeding, and the copper intrauterine device may increase it.
• •Depot medroxyprogesterone acetate causes a small, usually recoverable reduction in bone density; it can be used, including under 18, after considering alternatives, so it is considered carefully rather than automatically excluded.
• •Hormonal contraception has no clear consistent effect on performance; continuous or extended combined methods can suppress a withdrawal bleed, and norethisterone can delay a period but is not a contraceptive and is started in advance.
• •The iron benefit applies to methods that actually reduce bleeding, especially the levonorgestrel intrauterine system and suitable combined contraception.
• •Hormonal contraception obscures the spontaneous cycle, but amenorrhoea is only one sign of relative energy deficiency in sport; transdermal 17-beta-oestradiol with cyclical progesterone is not contraception and is a specialist, off-label option.