Birth Control and the female mountain athlete: What you need to know

When it comes to managing your cycle as a female athlete, there’s no one-size-fits-all solution and that includes the option of doing nothing at all. For some athletes, letting the natural cycle run its course is the right move. For others, the demands of high-altitude expeditions, long training blocks, or back-to-back race seasons make hormonal birth control a valuable tool not just for contraception, but for regulating symptoms, minimizing iron loss, or gaining predictability.

As a coach and athlete, I wish there were a clear, research-backed answer for what’s “best.” But like so much in women’s health, the truth is that every body, literally, is different. What works beautifully for one athlete might completely derail another. Hormones, performance, mood, recovery, bone health, and even confidence can all be influenced, for better or worse, depending on the method.

This article isn’t here to tell you what to do. It’s here to compare your options objectively, honestly, and through the lens of the female athlete. Whether you’re racing, guiding, or just logging long days in the mountains, you deserve clear information and the confidence to make a decision that fits your physiology and your goals.

The Complex Relationship Between Birth Control and Athletic Performance

Female athletes experience constant hormonal fluctuations throughout their lives, from puberty through menopause. The menstrual cycle itself made up of the follicular, ovulatory, and luteal phases affects not only reproduction but also key aspects of physiology like core temperature, cardiovascular efficiency, and injury susceptibility.

Hormonal birth control adds another layer by introducing synthetic (exogenous) hormones that override the body’s natural hormonal rhythm. While effective for preventing pregnancy, these synthetic hormones can impact physiological systems far beyond reproduction. For example:

• Estrogen influences metabolism, bone health, protein synthesis, and cardiovascular function.
• Progestins (synthetic progesterone) affect respiration and also act on neural pathways via widespread brain receptors.

Below, you’ll find a comparative summary of the evidence behind each method as it relates to key performance factors like aerobic capacity, strength, recovery, thermoregulation, and injury risk. To complement the science, I’ve also included athlete testimonials because while research gives us trends, lived experience often reveals the nuance.

1. Combined Oral Contraceptives (COCs)

Composition: Ethinyl estradiol + progestin

Delivery: Daily oral pill 

Common Brand: Alesse, Yaz, Ortho Tri-Cyclen

Performance Considerations:

• Cycle regulation: COC’s suppress the natural menstrual cycle and replace it with a steady dose of synthetic hormones. For athletes with irregular or painful periods, this can be a benefit.

• Hormonal stability: The pill blunts hormonal fluctuations, which may reduce cycle-related symptoms like bloating, mood swings, and fatigue potentially improving perceived performance consistency.

• Potential drawbacks: Some athletes report decreased aerobic capacity or VO₂max on the pill, possibly due to the effect of synthetic estrogen on plasma volume and thermoregulation.

• Nutrient impact: May lower levels of certain vitamins (B6, B12, folate) and minerals (magnesium, zinc), which can influence energy and recovery.

Performance Impacts: A Deeper Dive (Evidence):

• Aerobic Capacity:

A 2020 systematic review by McNulty et al. (Sports Medicine) found that COC users had slightly lower VO₂max compared to non contraceptive user controls (effect size −0.36), though the difference was generally small and of unclear practical relevance. Performance decline appears more likely in pills with higher estrogen doses (>35 mcg ethinyl estradiol).

• Substrate Utilization (How different fuel sources are utilized):

Estrogen promotes greater fat oxidation and spares glycogen during endurance exercise. COC use may reduce this, shifting metabolism toward higher carbohydrate use (Janse de Jonge, 2003).

• Thermoregulation:

Synthetic estrogens elevate core body temperature set points, which may impair heat dissipation in hot conditions (Tenan et al., 2022). Some athletes may perceive higher RPE during heat-exposed exercise while on COCs.

• Recovery and Muscle Adaptation:

A 2018 review (Elliott-Sale et al., Sports Med) suggests that COCs may blunt muscle protein synthesis slightly, though findings are inconsistent. Muscle protein synthesis is the natural metabolic process where your body builds new muscle proteins from amino acids, the mechanism that repairs and rebuilds muscle tissue after exercise and is crucial for muscle growth. 

• Injury Risk:

Estrogen influences collagen turnover and neuromuscular control. Some observational data suggest a modest reduction in ACL injury rates among COC users (Rahr-Wagner et al., 2014), but evidence is not conclusive.

Positive Testimonial (COC’s)

Athlete: Trail Runner & Climber

“The pill gave me back control over my training.”

“Before going on the pill, my cycle was all over the place; long one month, short the next, with cramps that would knock me out for days. I’d often lose 2–3 quality training sessions a month just trying to deal. Once I started a low-estrogen COC, I could actually plan races and peak workouts without guessing how I’d feel. My energy feels more consistent now.

I was worried it might affect my performance, but I haven’t noticed a drop in speed or strength. If anything, the reduction in monthly chaos has made me a better athlete.”

Negative Testimonial (COC’s)

Athlete: Nordic Skier

“It flattened everything, including my edge.”

“I tried the pill for six months hoping to reduce cramps and skin breakouts. While it did help there, I started to feel off in training. I couldn’t hit the same top-end intensity. I felt like I had no second gear.

I was also sweating more during hot workouts and had weird fatigue that didn’t line up with my workload. My coach and I eventually connected the dots and I decided to come off it. Within a few months, my pop came back.

For me, that hormonal ‘flatline’ wasn’t worth it but I know it works for others. Just track how you feel and don’t ignore your instincts.”

2.  Combined Hormonal Contraceptive (CHC)

Composition: Estrogen: Ethinyl estradiol

Progestin: Etonogestrel

Delivery: Hormones are delivered locally and systemically through transvaginal absorption.  The ring is inserted in the vagina for a period of 3 weeks, then removed for a one-week break at which time a withdrawal bleed typically occurs. Alternatively, the ring can be used continuously without replacing it with a new one but not taking a break. 

Common Brand: NuvaRing

Performance Considerations 

• Hormonal Stability The NuvaRing delivers a steady dose of ethinyl estradiol and etonogestrel, which reduces hormonal fluctuations compared to a natural menstrual cycle. This may help stabilize mood, reduce premenstrual symptoms, and provide more predictability across a training cycle.
• Heat Tolerance and Core Temperature
  Like other combined hormonal contraceptives, the NuvaRing can raise core body temperature slightly. This may reduce heat tolerance and increase perceived effort during training or competition in hot environments particularly during long-duration or high-intensity sessions.
• Adaptation and Recovery
  There is limited evidence that NuvaRing use negatively impacts VO₂max, strength, or endurance gains. Most available research shows no major performance deficits in users, though studies on elite athletes are lacking.
• Menstrual Suppression and Cycle Control
  NuvaRing can be used continuously to suppress bleeding, which some athletes use strategically to avoid menstruation during key training blocks or competitions. This can reduce cramping, fatigue, or logistical challenges tied to monthly periods.
• Mood and Side Effects
  Some users report mood changes, nausea, breast tenderness, or low energy especially during the adjustment period. While these effects are generally mild and transient, even small disruptions can influence training consistency or perceived exertion.
• Muscle Gain and Strength
  There is minimal research on how NuvaRing specifically affects muscle growth. Some studies suggest that combined hormonal contraceptives may slightly blunt strength or lean mass gains in untrained populations, but data in trained athletes is limited and inconclusive.

Positive Testimonial (CHC)

Athlete: Triathlon
“Using the NuvaRing gave me way more stability, no more guessing when my period would hit mid-race week. I felt like I could plan my training around predictable energy levels instead of riding a hormonal rollercoaster. I even used it continuously during race season to skip my period altogether, which helped me feel more in control.”

 Negative Testimonial (CHC)

Athlete: Track Cyclist
“The first few months on the NuvaRing, I felt off. My energy was low during workouts, and I couldn’t figure out why intervals felt harder than usual. I also felt warmer during long sessions, especially in the heat. Eventually I switched to a different method that didn’t affect me as much.”

3. Progestin-Only Pills (POPs)

Composition: Progestin

Delivery: Daily oral pill (no estrogen)

Common Brands: Camila, Slynd, Errin

Performance Considerations:

• Minimal impact on estrogen: These pills don’t contain estrogen and therefore may not blunt performance markers in the same way as combined pills.

• Unpredictable bleeding: Some users experience irregular spotting, which can be frustrating for athletes planning for races or key events.

Performance Impacts a Deeper Dive (Evidence):

• Cardiovascular Effects:

Lacking the vascular benefits of estrogen, POPs may have a neutral to mildly negative effect on endothelial function; no clear performance impact has been identified. Endothelial function refers to how well the endothelium, which is the thin layer of cells lining the inside of blood vessels, regulates vascular tone, blood flow, clotting, immune function and inflammation. It plays a key role in cardiovascular health and performance. 

• Bleeding Patterns:

Irregular bleeding or spotting is common and can cause discomfort or training interruptions, though this is not a physiological barrier to performance.

• Research Gap:

Few studies isolate the effect of POPs on athletic performance.

Positive Testimonial (POPs)

Athlete: Marathoner

“Simple, stable, and no estrogen side effects.”

“I went on the mini-pill because I’d had issues with estrogen-based pills in the past, headaches, mood swings, and just feeling off. The progestin-only option has been a game changer for me.

I haven’t noticed any performance drop, and my training feels steady. I don’t get big hormonal swings, and I like that I’m not suppressing ovulation completely just enough to prevent pregnancy. My period still comes, but it’s super light.

It’s been low-maintenance and hasn’t messed with my recovery or motivation at all. I’m glad I gave it a try.”

Negative Testimonial (POPs)

Athlete: Road Cyclist

“The random bleeding drove me crazy.”

“I wanted to try the progestin-only pill because I didn’t want the risks of estrogen, but honestly it didn’t work well for me. My cycle became unpredictable. I never knew when I’d be bleeding, and sometimes it would drag on for over a week.

It wasn’t painful, but it was disruptive. Planning long rides, stage races, or travel got tricky. I also noticed a dip in mood that crept in after a few months.

Performance-wise, I didn’t feel slower, but the mental load of unpredictability was enough to switch back to something more consistent. It might be a good option for others, but it just didn’t fit my lifestyle as an athlete.”

4.  Hormonal IUD

Composition: Localized progestin

Delivery: Intrauterine device

Common Brands: Mirena, Kyleena

Performance Considerations:

• Stable hormonal environment: Because the hormone is delivered locally to the uterus, systemic hormone levels remain relatively low.

• Cycle control: Many users experience lighter periods or amenorrhea (no periods), which may reduce iron loss and improve day-to-day comfort during training blocks.

• Minimal systemic side effects: Less impact on metabolism and cardiovascular markers compared to oral options.

• Insertion side effects: Some athletes experience cramping or bleeding in the first few months post-insertion, which can temporarily affect training quality.

Performance Impacts: A Deeper Dive (Evidence):

• Systemic Hormonal Effect:

IUDs deliver low-dose progestin locally, resulting in lower systemic hormone levels than oral contraceptives. Therefore, their impact on metabolism, thermoregulation, or cardiovascular function is minimal (Nelson et al., 2010).

• Menstrual Suppression and Iron Status:

Up to 80% of users experience lighter periods or amenorrhea, which may benefit endurance athletes prone to iron-deficiency anemia (Gibson et al., 2020).

• Training Interruptions Post-Insertion:

The first 1–3 months may include cramping, irregular bleeding, or discomfort that affects training consistency, but these side effects typically resolve.

Positive Testimonial (Hormonal IUD)

Athlete: Triathlete

“No periods, no problem and no performance dip.”

“Getting the hormonal IUD was one of the best decisions I’ve made as an athlete. My periods used to wipe me out for days of low iron, cramps, and missed training. A few months after getting the IUD, my period basically disappeared.

My energy became so much more consistent throughout the month. I’m less stressed about races lining up with bad cycle days, and I’ve had fewer iron issues.

The best part? I didn’t notice any negative impact on my endurance, recovery, or strength. It’s like a set-it-and-forget-it option that supports both my lifestyle and my performance.”

Negative Testimonial (Hormonal IUD)

Athlete:  Backcountry Skier & Trail Runner

“The first few months were rough.”

“I was sold on the hormonal IUD because of how many athletes rave about it, but my experience didn’t start out great. The insertion was more painful than I expected, and for the first two to three months, I had cramping and spotting all the time.

Training felt harder not because of hormones, but because I was constantly uncomfortable. Long skis and runs were distracting. It did settle down eventually, but the adjustment period was longer than I thought.

Now things are better, but if you’re planning a big season, I’d say get it well in advance so you’re not managing side effects during key training blocks.”

5. Copper IUD (Non-Hormonal)

Composition: No hormones

Delivery: Intrauterine device

Common Brands: Paragard, Mona Lisa

Performance Considerations:

• No systemic hormone impact: This is the only long-term method that does not affect hormones at all.

• Increased bleeding for some: May cause heavier or more painful periods, especially in the first year, something to consider for endurance athletes at risk of iron-deficiency anemia.

• Steady-state physiology: Ideal for athletes who want consistent hormonal patterns without synthetic input.

Performance Impacts:  A Deeper Dive (Evidence):

• Hormone-Neutral:

No alteration of the menstrual cycle’s natural hormonal pattern. As such, performance fluctuations remain cyclic.

• Heavier Periods:

Common in the first 6–12 months; may increase risk of iron deficiency, particularly in endurance athletes with marginal iron status (Peeling et al., 2007).

• No systemic side effects:

Favorable for those seeking contraceptive effectiveness without hormonal interference.

Positive Testimonial (Copper IUD)

Athlete: Ultra Runner

“Hormone-free and no performance changes.”

“I chose the copper IUD because I didn’t want to mess with my hormones. I like understanding my natural cycle it helps me track recovery, energy, and nutrition.

It hasn’t affected my training at all. I can still push hard, my strength and endurance feel the same, and mentally I’m sharp. I did get heavier periods at first, but nothing unmanageable and it actually reminded me to take my iron more seriously, which helped overall.

For me, the biggest win is that I feel completely in tune with my body, and my training cycles reflect that.”

Negative Testimonial (Copper IUD)

Athlete: Road Cyclist

“The bleeding and cramping wore me down.”

“I wanted a non-hormonal option because I’d had mood issues on the pill, but the copper IUD ended up being tough. My periods got way heavier like, changing a super tampon every few hours and the cramping was no joke.

It messed with my recovery and left me feeling drained, even with supplements. I was low energy during my period every month, and it made me dread that part of the cycle.

After a year, I gave up and switched to a hormonal IUD, which lightened everything. I know some athletes love the copper option, but it just didn’t work for my physiology.”

6. Progestin Implant 

Composition: Progestin

Delivery: Subdermal (below the skin) implant (3 years)

Common Brand: Nexplanon

Performance Considerations:

• Long-term low-dose hormone: Like IUDs, this provides hormonal stability but with a slightly higher systemic level.

• Bleeding irregularities: Common, and unpredictable spotting can be disruptive.

• Minimal maintenance: Great for athletes who travel frequently or need reliable contraception without daily tracking.

Performance Impacts:  A Deeper Dive (Evidence):

• Systemic but Stable:

Delivers a consistent low dose of progestin. Hormonal fluctuations are minimized, but irregular bleeding is common (Barrett et al., 2021).

• Impact on Strength and Endurance:

Largely unstudied, but likely similar to low-dose oral progestin effects i.e., negligible systemic impact for most athletes.

Positive Testimonial (Implant)

Athlete: Mountain Biker

“It’s set-it-and-forget-it and it hasn’t touched my training.”

“I got the implant three years ago and honestly, I forget it’s even there. I love that I don’t have to think about a pill or track anything for birth control.

Performance-wise, I haven’t noticed any downsides. My strength cycles and aerobic fitness feel steady. I still get a light period every few months, but it’s not disruptive, and I don’t feel hormonal swings or crashes.

For someone like me training in remote places, on skis or a bike for hours it’s exactly what I needed: zero maintenance, no performance dip, and no guesswork.”

Negative Testimonial (Implant)

Athlete:  Swimmer

“I couldn’t predict my cycle and it threw me off mentally.”

“I liked the idea of the implant because of how low-effort it is, but it ended up being way more unpredictable than I expected. I spotted on and off for months sometimes bleeding lightly for two weeks straight and it made training and racing uncomfortable.

The worst part was not knowing when it would happen. I couldn’t plan around it, and mentally it made me anxious before big meets.

Physically I felt okay, no weight gain or strength changes but the irregularity was a dealbreaker. I had it removed after a year and switched to something more predictable.”

7. Injectable Contraceptives

Composition: Progestin

Delivery: Intramuscular injection (every 12 weeks)

Common Brand: Dep-Provera

Performance Considerations:

• Bone mineral density loss: Long-term use has been linked to reductions in BMD, which is a concern for female athletes in weight-bearing or high-impact sports.

• Amenorrhea common: Can eliminate periods altogether, which some athletes find beneficial.

• Potential weight gain or mood changes: Not universal, but notable enough that many elite athletes avoid this option.

Performance Impacts: A Deeper Dive (Evidence):

• Bone Mineral Density (BMD) Reduction:

Strong evidence links Depo-Provera to BMD loss, especially in young athletes (Cromer et al., 2004). This is a significant concern in weight-sensitive sports (running, climbing, gymnastics).

• Menstrual Suppression:

Amenorrhea is common and may be seen as beneficial by some athletes, but the hormonal environment is not physiologically “neutral.”

• Weight Gain and Mood Changes:

Observed in a subset of users, which may impact training indirectly through altered motivation or comfort.

 Positive Testimonial (Injections)

Athlete: Strength Coach

“No period, no stress and my training feels steady.”

“I switched to the Depo shot about two years ago and haven’t had a period since which honestly feels like a huge relief. As someone who competes in high-impact races with water, mud, and random start times, not worrying about cramps or bleeding is a game-changer.

I haven’t noticed any dip in performance. My lifting numbers are stable, my recovery feels good, and I appreciate only needing to think about it once every three months.

I know there are concerns about bone density, so I track my vitamin D and calcium and do regular DEXA scans but so far, no red flags. It works really well for my lifestyle.”

Negative Testimonial (Injections)

Athlete: Trail Runner

“It wrecked my bone health and delayed my comeback.”

“I used Depo-Provera for just over a year and didn’t realize how much it was affecting my body until it was too late. My period stopped, which at first I thought was a plus, but I also started getting more sore and slower to recover.

After a minor foot fracture during base season, I had a DEXA scan and it showed low bone density, and my doctor linked it to the shot. I stopped using it right away, but it took months for my cycle to return and longer to feel strong again.

I wish I’d known about the risks ahead of time, especially as a younger endurance athlete. It might work for some, but I’d never recommend it to someone in a high-load, bone-stress sport.”

Side Effects and the Research Gap

One of the greatest challenges in understanding how hormonal birth control affects athletic performance is the glaring lack of rigorous, athlete-specific research. While a handful of studies have explored links between contraceptive use and outcomes like VO₂max, muscle gain, or body composition, most are outdated, underpowered, or based on recreational not elite populations.

For instance, early suggestions that the pill might impair aerobic capacity or blunt muscle growth came from studies using high-dose formulations or untrained participants. More recent research often contradicts those findings, but still fails to account for the demands of high-level sport. As one expert bluntly stated: “The research is just crappy.”

What’s more overlooked are the everyday side effects: fatigue, mood changes, nausea, breast tenderness. These are rarely studied in athletes, but for those training at the edge of their physical limits, even minor disruptions can derail consistency and progress. When recovery, energy availability, and neuromuscular efficiency are all dialed to the margin, a single poorly-timed side effect can have outsized consequences.

Some athletes describe feeling sluggish, heavy, or off while on hormonal birth control, with clear rebounds in performance after stopping. But without high-quality, athlete-specific studies, it’s difficult to move beyond anecdotes.

Ultimately, female athletes are navigating a complex and highly individualized hormonal landscape with little guidance from science. The current body of evidence doesn’t reflect the lived realities of elite sport leaving athletes and coaches to rely on trial, error, and personal experience in place of research that should already exist.

So What Can You Do?

There’s no one-size-fits-all answer. Most studies suggest that hormonal birth control doesn’t significantly hinder performance for most athletes but individual responses vary widely. Some may experience changes in perceived exertion, recovery time, or emotional regulation. Tracking symptoms over time is key.

Bottom Line for Female Athletes:

• Educate Yourself: Read articles like this one and some of the resources cited below. Fully understand what you are taking and possible benefits and side effects. 

• Track & trial: Keep a training log and note any changes after starting a new method. Also consider using a period tracking app or method to notice trends and make your symptoms more predictable.

• Prioritize iron and nutrient monitoring: especially if you use a method that affects bleeding.

• Talk to a doctor and your Coach: Make sure your advisors understand sport-specific demands, not just general medicine.

• Listen to your body: If performance dips noticeably or symptoms are disruptive, it may be worth trialing a different method.

Navigating birth control as a female mountain athlete isn’t just about managing contraception, it’s about understanding your body, your performance, and your needs. This is a normal, healthy part of being female, and there is absolutely no shame in talking about it. In fact, we need to talk about it more. A good coach should be open, informed, and receptive to how you feel whether you’re crushing intervals or dealing with cramps. Let’s normalize this conversation.

If you’re looking for a coach who understands the physiological, emotional, and logistical layers of being a female athlete and who won’t shy away from these conversations the coaches at Evoke are happy to help. Reach out any time. Your body is not a liability; it’s your greatest tool. Let’s train it with intention.

Suggested Resources:

• Sims, S., & Yeager, S. (2016). ROAR: How to Match Your Food and Fitness to Your Unique Female Physiology for Optimum Performance, Great Health, and a Strong, Lean Body for Life. Rodale Books.
• Noordeloos, K. (2023). The Female Body Bible: A Revolution in Female Health and Performance. Human Kinetics.
• Briden, L. (2018). The Period Repair Manual: Natural Treatment for Better Hormones and Better Periods (2nd ed.). Pan Macmillan.
• Briden, L. (2021). Hormone Repair Manual: Every Woman’s Guide to Healthy Hormones After 40. Pan Macmillan.
• Thompson, M. (2021). Strong Like Her: A Celebration of Rule Breakers, History Makers, and Unstoppable Athletes. Simon & Schuster.
• Natterson, C. (2009). The Care and Keeping of You 2: The Body Book for Older Girls. American Girl Publishing. (Good for teen athletes new to birth control conversations)
  • Nordic, C. (2011, August 8). “It shouldn’t be at all surprising”: A link between birth control and performance. FasterSkier. https://fasterskier.com/2011/08/it-shouldnt-be-at-all-surprising-a-link-between-birth-control-and-performance/

Studies Cited in this Article:

• McNulty et al., Sports Medicine (2020) – “The Effects of Oral Contraceptives on Exercise Performance”

• Elliott-Sale et al., Sports Medicine (2018) – “Hormonal Strategies for Female Athletes”

• Janse de Jonge, Sports Medicine (2003) – “Effects of the Menstrual Cycle on Exercise Performance”

• Rahr-Wagner et al., The American Journal of Sports Medicine (2014) – “Oral Contraceptives and ACL Injury Risk”

• Peeling et al., International Journal of Sport Nutrition and Exercise Metabolism (2007) – “Iron Status in Female Athletes”