HORMONAL CONTRACEPTIVES & FOOTBALL DR TESSA R FLOOD PHD, PROFESSOR KIRSTY

What are hormonal contraceptives?

Hormonal contraceptives (HC) contain exogenous [external] synthetic hormones that act via negative feedback on gonadotrophic hormones resulting in the chronic downregulation of the hypothalamic-pituitary-ovarian axis and endogenous [internal] ovarian sex hormones. The long-term reduction of endogenous oestrogen and progesterone [the ovarian sex hormones] removes the cyclic fluctuations in these hormones associated with the phases of the menstrual cycle. By inhibiting the production of the ovarian hormones, HC reduce the chance of pregnancy by thickening cervical mucus, thinning the lining of the endometrium, and inhibiting ovulation. HC are designed to prevent pregnancy but are also used for a variety of other reasons, for example: to alleviate symptoms of dysmenorrhea (painful periods), lighten or prevent bleeding, prevent acne, reduce variation in cycle lengths, and to treat other medical issues. When discussing athletic performance and contraceptive choices, it is important to remember that it is a women’s right to choose to take HC.

How common is hormonal contraceptive usage?

HC are estimated to be used by around 49% of athletes1 in the United Kingdom (UK) and around 30% of the general population2. In a recent audit of the Women’s Super League in the UK, 28% of players reported current hormonal contraceptive use with 43% being previous users.

What are the most common types of hormonal contraceptives?

Common types of HC in the UK include the combined contraceptive pill (OCP), progestogen-only pill (mini-pill), patch, vaginal ring, implant, injection, and intrauterine systems. The use of these HC within sport depends on numerous factors, including the location [country] of the athlete. In the UK combined monophasic OCPs are available from pharmacies by prescription and are the most common type of HC used. Table 1 shows the contraceptive types and brand names available in the UK.

A cis gendered naturally menstruating women (cycle length 21-35 days) will experience menstruation (also known as menses or having their period) once per menstrual cycle. A period is the shedding of the endometrium layer, which has been built and sustained to allow a fertilised egg to embed. Many women taking HC still bleed; however, these are called withdrawal bleeds and occur due to the fluctuations in synthetic hormones. Withdrawal bleeds do not represent physiological menstruation. As Table 1 shows, many women taking HC stop getting a regular bleed and the effects of HC on bleeding patterns are highly individual. Parker et al.,3 reported that, in 21 elite female Women’s Super League players using HC, 29% (n=6) still got a regular withdrawal bleed and 29% (n=6) stopped bleeding, with the other 42% having infrequent bleeds. Athletic populations have reported using the OCP to manipulate the timing of or omit the withdrawal bleed to reduce the perceived and actual impact of this bleed on performance1

Pills

Monophasic combined pill e.g., Microgynon®, Yasmine®, Rigevidon®, Levest, Lucette

Monophasic combined pill (28-day preparations) e.g., Microgynon® 30 ED, Femodene® ED

Phasic [bi or tri] combined pill e.g., Logynon

Phasic [bi or tri] combined pill (28-day preparations) e.g., Logynon® ED, Qlaira®**

Progestogen-only pill e.g., Norgeston, Cerazette

Cyclic Contraceptives

Vaginal ring e.g., NovaRing

Patch e.g., Evra

Long-Acting Reversible Contraceptives

Implant e.g., Nexplanon®

Injection e.g., Depo-Provera, Noristerat

Intrauterine System (IUS) e.g., Mirena®, Jaydees®, Levosert®, Kyleena®

Ethinylestradiol & Progestogen

21 pills per packet (constant hormonal exposure)

7-day pill free break

Yes, in the 7-day break (lighter)

May experience spotting

Ethinylestradiol & Progestogen 28 pills per packet (21 active, 7 inactive) Yes, in the 7 inactive pills

Ethinylestradiol & Progestogen

Ethinylestradiol & Progestogen

21 pills per packet (3 sections with different concentrations of hormones) 7-day pill free break

28 pills per packet (3 or 4 sections with different concentrations of hormones)

Contains active and inactive pills

Progestogen 28 pills per packet, no break between pill packets

Ethinylestradiol & Progestogen

Ethinylestradiol & Progestogen

Each ring lasts 21 days 7-day break

Each patch lasts 7 days (use for 21 days) 7-day break

Progestogen 3 years

Progestogen One injection every 8-13 weeks

Progestogen 3-5 years (depending on brand)

Yes, in the 7-day break (lighter)

May experience spotting

Yes, in the inactive pills

Less Frequent (lighter, less heavy)

May experience spotting

Yes, in the 7-day break (lighter)

Yes, in the 7-day break

Stop or less frequent (lighter)

Irregular or stop (heavier or lighter)

Stop or less frequent (heavier 3-6 months)

*Please note, this is just the general advice on withdrawal bleeds, however, this response is highly individual and can differ both between and within women.

** Qlaira contains 26 active pills and 2 inactive, Logynon® ED contains 21 active and 7 inactive pills

HC change the hormonal profile; natural/endogenous oestrogen and progesterone are supressed and are replaced by synthetic ethinylestradiol and progestogen. Figure 1 shows a graphical representation of hormonal profiles that occur when using HC in comparison with a women’s natural menstrual cycle. It is important to note that the amount of synthetic hormone in each brand of contraceptive is different (Table 2) and hence the side effects and impact of HC on an individual can vary. The impact of HC on women are highly individual and there is not a one size fits all option.

Players taking HC do not have the same hormonal patterns as naturally menstruating women (i.e., eumenorrheic women) therefore players should not experience ‘phased based symptoms’ (i.e., symptoms that correspond with phases of the menstrual cycle). Indeed, HC are often used to minimise or alleviate symptoms of the menstrual cycle. As such, players should try different types of HC if they are experiencing symptoms as it might be that they have not found their best fit yet. Parker et al.,3 showed that negative symptoms (e.g., mood swings, weight gain) were higher in progestogen-only HC compared to combined HC (63 vs.

23%). Progestogen-only contraceptives are prescribed when combined contraceptives are contra-indicated or can be due to personal preference. Their higher rates of self-reported symptoms, compared with combined contraceptives, should be considered when both types are an option. In a recent survey around 40% of athletes who take a monophasic OCP perceived [thought] that their physical performance was reduced during the pill free week in comparison with pill taking weeks, which corresponds to withdrawal bleeding and increased symptomology4

How do hormonal contraceptives affect female footballers?

To date, around 6% of the research in sport and exercise science has been conducted exclusively on women5. Women account for approximately 34% of the participants studied between 2014 and 2020 when you also include studies that have used both men and women. These statistics highlight how little research is conducted on women and, as such, how little we know about female athletes and women footballers. Most studies in women have failed to account for hormonal fluctuations of the menstrual cycle or for HC.

Review papers are a type of scientific article that summarise previous research on a particular topic. In addition, they often comment on how good [research quality] the studies were. They can be useful for getting a broad overview on a topic and a sense of how much confidence practitioners should have in the findings from previous studies.

A recent review paper6 - published in 2020 - included 30 studies comparing performance in women taking OCPs and naturally menstruating women (n=597 participants) and 24 studies comparing pill phase and pill free phase in women taking OCPs (n=221 participants). A review on chronic adaptations to strength training7 - published in 2019 - consisted of 2 studies comparing women taking OCPs and naturally menstruating women (n=59 participants). In a review on recovery following exercise induced muscle damage8 – published in 2022 - comparing women taking OCP and women with a natural menstrual cycle 4 studies were included (n=66 participants). As illustrated by the small number of studies included in these reviews more research is needed in women on sex-specific factors including the effects of HC on sport and exercise outcomes so that we can use these data to provide evidence-based practice for use in elite women’s football.

Data6 - from multiple research studies that compared performance (strength and endurance outcomes) changes in women taking OCP between the pill and pill-free days and between OCP users and naturally menstruating women - concluded that there was no difference in performance between the pill phase and the pill-free phase6. In comparison to naturally menstruating women a ‘trivial’ [extremely small] reduction in performance was seen in OCP users. However, the real life implications of these findings are likely to be (i) small and therefore not meaningful and (ii) will not affect every OCP user6. While, using OCPs might exert a slightly negative impact on performance the size and inconsistency of this effect between studies and between women, support consideration of an individual’s response and requirements of each player.

A recent review paper compared the effect of OCPs on chronic strength adaptations between naturally menstruating women and women taking an OCP7. In the two studies reviewed, no differences were seen between the OCP users and naturally menstruating women following +10-weeks of resistance training. Since this paper was published, additional studies have also showed no differences in strength adaptations9–11. One study suggested impairment in muscle gain with OCP use but that this impairment was not large enough to impact strength adaptations in comparison with naturally menstruating women12

Four studies have compared recovery from exercise induced muscle damage in women taking OCPs and naturally menstruating women8. Collectively their data showed that recovery was slightly impaired in OCP users compared with naturally menstruating women. This impairment was shown by a potential for lowered muscle strength, elevated markers of muscle damage, and greater perceived muscle soreness. However, the size and variability of the effect between studies and between women, support consideration of an individual’s response and requirements of each player.

As well as a lack of research in women, there is also an absence of high quality [credible] research. In the recent review on exercise performance in women taking OCP6, 64% of papers were deemed medium or low quality. These studies had hormonal contraceptive specific methodological issues. For example, some studies grouped different HC together, despite the different hormonal profiles as shown in Figure 1. This makes it difficult to see the effect different HC have on performance, strength, or recovery. In addition, the review papers above7,8 didn’t examine the methods regarding hormonal contraceptive specific methodological issues (i.e., types/ brand of HC) which can make it difficult to

draw robust conclusions for players and practitioners. It is also important to consider that all the studies listed above have focused on OCP use and none of the other types listed in Table 1. Due to differences in these contraceptive methods, we cannot generalise findings in OCPs to other HC.

- From a practical viewpoint, the group effects seen in performance and recovery are ‘trivial’ and variable across studies and between women and therefore warrants no general guidance on HC in sport.

- Each player should consider all relevant factors (physical, emotional, practical, financial and health related aspects) including their own response to and requirement for HC and that individuals do not solely make their decision to use or not use HC based on the findings in the literature.

In 2023, with many players choosing to use HC it is frustrating that we do not more about how HC impact performance. One of the difficulties faced with the range of HC available to women (Table 1) is the differences in type of hormone and concentration of these hormones. Within OCPs for example, there are four different generations of OCP, each generation has a different synthetic progestogen and concentration. Table 2 highlights the differences between monophasic OCP brands. Second generation OCPs are used majority of research as they have the highest prevalence.

The main take home messages are,

• Many players choose to use HC as a convenient method to provide contraception.

• In many cases, this reduces or alleviates menstrual cycle related symptoms and eliminates or lightens bleeding making it a popular choice in sport.

• Research suggests that performance is stable across OCP phases, but that more high-quality research is needed into different types of HC to provide guidelines for practitioners and players.

• Whilst there is some evidence for decreased performance and recovery in comparison to athletes with a natural menstrual cycle, this reduction is ‘trivial’ and highly variable between women and the use of HC should be made on what is best overall for that player.

1. Martin D., Sale C., Cooper SB., Elliott-Sale KJ. Period Prevalence and Perceived Side Effects of Hormonal Contraceptive Use and the Menstrual Cycle in Elite Athletes. Int J Sports Physiol Perform. 2018;13(7):926-932. doi:10.1123/ijspp.2017-0330

2. Cea-Soriano L, Garcia Rodriguez LA, Machlitt A, Wallander MA. Use of prescription contraceptive methods in the UK general population: a primary care study. BJOG An Int J Obstet Gynaecol. 2014;121(1):51-53. doi:10.1111/1471-0528.12465

3. Parker LJ, Elliott-Sale KJ, Hannon MP, Morton JP, Close GL. An audit of hormonal contraceptive use in Women’s Super League soccer players; implications on symptomology. Sci Med Footb. 2022;6(2):153-158. doi:10.1080/24733938.2021.1921248

4. Ekenros L, von Rosen P, Solli GS, et al. Perceived impact of the menstrual cycle and hormonal contraceptives on physical exercise and performance in 1,086 athletes from 57 sports. Front Physiol. 2022;13(August):1-13. doi:10.3389/fphys.2022.954760

5. Cowley ES, Olenick AA, McNulty KL, Ross EZ. “Invisible Sportswomen”: The Sex Data Gap in Sport and Exercise Science Research Women Sport Phys Act J. 2021;29(2):146-151. doi:10.1123/WSPAJ.2021-0028

6. Elliott-Sale KJ, McNulty KL, Ansdell P, et al. The Effects of Oral Contraceptives on Exercise Performance in Women: A Systematic Review and Meta-analysis. Sport Med. 2020;50:1785–1812. https://doi.org/10.1007/s40279-020-01317-5

7. Thompson BM, Drover KB, Stellmaker RJ, Sculley D V., Janse de Jonge XAK. The effect of the menstrual cycle and oral contraceptive cycle on muscle performance and perceptual measures. Int J Environ Res Public Health. 2021;18(20). doi:10.3390/ijerph182010565

8. Glenner-Frandsen A, With C, Gunnarsson TP, Hostrup M. The Effect of Monophasic Oral Contraceptives on Muscle Strength and Markers of Recovery After Exercise-Induced Muscle Damage: A Systematic Review. Sports Health. 2022;XX(X):1-10. doi:10.1177/19417381221121653

9. Romance R, Vargas S, Espinar S, et al. Oral Contraceptive Use does not Negatively Affect Body Composition and Strength Adaptations in Trained Women. Int J Sports Med. 2019;40(13):842-849. doi:10.1055/a-0985-4373

10. Sung ES, Han A, Hinrichs T, Vorgerd M, Platen P. Effects of oral contraceptive use on muscle strength, muscle thickness, and fiber size and composition in young women undergoing 12 weeks of strength training: a cohort study. BMC Womens Health. 2022;22(1):1-10. doi:10.1186/s12905-022-01740-y

11. Dalgaard LB, Jørgensen EB, Oxfeldt M, et al. Influence of Second Generation Oral Contraceptive Use on Adaptations to Resistance Training in Young Untrained Women. J Strength Cond Res. 2022;36(7):1801-1809. doi:10.1519/JSC.0000000000003735

12. Riechman SE, Lee CW. Oral Contraceptive Use Impairs Muscle Gains in Young Women. J Strength Cond Res. 2022;36(11):3074-3080 doi:10.1519/JSC.0000000000004059