Preparing for Pregnancy as an Athlete: Fueling for a Strong Start

Hi there! I'm Rebekah - Sport Dietitian, Mama to a beautiful 2 year old boy, and an athlete myself (not the elite kind - the train hard for my own kuddos). I live, work, and train in the city of Ottawa, Ontario.

When I was preparing for pregnancy and going through my pregnancy and postpartum with my son, I was shocked at how little information and support there was for athletic mamas like me. It's already such a scary and confusing time, wrought with misinformation - add the effort of trying to maintain my athleticism and you have quite the head-scratcher. That's why I've decided to do a little series here in my blog to help my athletes who are looking to become pregnant, who are currently pregnant, and those who are into their postpartum journey. Let's take a look at some of the nutrition challenges facing athletic females as they embark on these life changes.

For athletic women, preparing for pregnancy isn’t about stepping away from performance - it’s about supporting your body for one of the biggest physical events of your life. Just like you wouldn’t start a new training block without a plan, it’s worth taking a thoughtful approach to nutrition as you move into this next chapter.

1. Meeting Energy Demands

Many athletes enter pregnancy with energy needs already close to their training threshold. Undereating before conception can affect menstrual regularity, fertility, and hormonal balance (Mountjoy et al., 2018). During early pregnancy, energy needs don’t increase dramatically, but it’s important to avoid restrictive eating or attempting weight loss. I repeat - attempting weight loss can interfere with your goals of becoming pregnant. Instead, focus on maintaining regular fueling patterns with balanced meals and snacks every 3 - 4 hours and strategic fueling and recovery nutrition around your training sessions to support both performance and early fetal development.

2. Micronutrient Priorities

Certain micronutrients become especially important in the preconception and early pregnancy stages:

• Folate: critical for neural tube development; aim for 400 - 600 mcg daily from food and/or a prenatal (Health Canada, 2022).

• Iron: athletes with low iron stores are at greater risk of deficiency during pregnancy; monitor ferritin regularly.

• Calcium and Vitamin D: essential for bone health and fetal skeletal development.

• Choline: often overlooked but vital for brain development - eggs, lean meats, and fortified foods are excellent sources.

Meeting these needs through a well-balanced diet and a high-quality prenatal supplement is key.

3. Choosing a Safe Prenatal Supplement

Health authorities recommend taking a prenatal vitamin (or at least a multivitamin containing ~400 mcg folic acid) at least 3 months before conception, in order to build nutrient stores and cover nutrient‐sensitive windows (e.g. neural tube closure) that occur early in pregnancy. (Canada’s Public Health Agency, 2022; Cleveland Clinic, 2024; Mayo Clinic).

It can be confusing trying to find a good prenatal as not all prenatals are created equal. Look for third-party tested brands (e.g., NSF Certified for Sport or Informed Choice) to minimize contamination risk and ensure label accuracy - a particularly important step for athletes who are drug-tested. Prenatals should contain at least 400 mcg folate, 27 mg iron, vitamin D, and iodine. Avoid megadoses unless prescribed by your healthcare provider.

4. Supplements and Ergogenic Aids to Rethink

Many common sport supplements have limited evidence for safety in pregnancy or may pose potential risks. It is important to take a pause on these supplements during this time.

• Caffeine: moderate intake (≤200 mg/day) is generally considered safe (ACOG, 2020).
  

• Beta-alanine, and nitric oxide boosters: not well studied in pregnancy — best discontinued.
  

• BCAAs (Branched-Chain Amino Acids): While BCAAs are naturally present in protein-rich foods, there is insufficient evidence regarding supplemental BCAA use in pregnancy. Excessive intake may alter amino acid balance and has not been evaluated for fetal safety (ACOG, 2020; Thomas et al., 2016). Meeting protein needs through food sources remains the preferred and safest strategy.
  

• Sodium bicarbonate: Commonly used as a buffering agent to delay fatigue in high-intensity exercise, sodium bicarbonate supplementation can cause gastrointestinal discomfort, fluid shifts, and altered acid-base balance (Peart et al., 2019). Its safety in pregnancy has not been studied, and potential risks outweigh any ergogenic benefit. Avoid use during pregnancy.
  

• Creatine: Emerging evidence suggests that creatine supplementation may be safe during pregnancy. Animal studies show no adverse effects on gestational outcomes and potential benefits for fetal protection during birth stress (Ellery et al., 2016; Ireland et al., 2023). Observational human data also indicate stable maternal creatine metabolism throughout gestation (Leite et al., 2024). However, randomized controlled trials in pregnant women are lacking. Until more is known, athletes should only consider use if they've already been using creatine without issue, use only third-party tested products and consult their healthcare provider before continuing supplementation.
  

• High-dose herbal or “fat-burning” products: should be avoided due to unpredictable effects.When in doubt, consult your sport dietitian before continuing any supplement into pregnancy.
  

5. Bottom Line

Preparing for pregnancy as an athlete means honoring your body’s changing demands while carrying your performance mindset into a new phase. Focus on consistent fueling, adequate micronutrient intake, and supplement safety. With a proactive approach, you can set a strong foundation for both your pregnancy and your athletic identity.

Ready to Level Up?

You’re already putting time, money, and energy into your sport. Make sure you’re fueling that effort the right way, especially for big life changes! Investing in a sport dietitian isn’t just about food - it’s about maximizing your performance, health, and confidence.

Are you ready to take the next step in honing in your nutrition strategies for your active lifestyle? Connect with me to book your FREE DISCOVERY CALL and let's get started!

Are you an athlete, parent of an athlete or a coach? Sport nutrition is often a missing piece of the performance puzzle for young, developing athletes. Check out my other biz, BUILT TO PERFORM, and see how we can help you educate and support your team. From nutrition education sessions to being on the ground at training camps and competitions. We are here to help take the guesswork out of nutrition.

References

American College of Obstetricians and Gynecologists (ACOG). (2020). Moderate caffeine consumption during pregnancy.Retrieved from https://www.acog.org

Cleveland Clinic. (2024). Pregnancy: Prenatal vitamins.Retrieved from https://my.clevelandclinic.org/health/drugs/9754-pregnancy-prenatal-vitamins

Ellery, S. J., Della Gatta, P. A., Bruce, C. R., & Dickinson, H. (2016). Maternal creatine supplementation prevents birth asphyxia-induced injury in the newborn spiny mouse. American Journal of Obstetrics and Gynecology, 215(4), 507.e1–507.e7.https://doi.org/10.1016/j.ajog.2016.05.019

Government of Canada, Health Canada. (2022). Folate: Prenatal nutrition guidelines for health professionals.Retrieved from https://www.canada.ca/content/dam/hc-sc/migration/hc-sc/fn-an/alt_formats/hpfb-dgpsa/pdf/pubs/folate-eng.pdf

Institute of Medicine (IOM). (2005). Dietary reference intakes for energy, carbohydrate, fiber, fat, fatty acids, cholesterol, protein, and amino acids. National Academies Press.https://doi.org/10.17226/10490

Ireland, Z., Dickinson, H., Ellery, S. J., & Snow, R. J. (2023). Maternal creatine supplementation: A potential strategy to improve fetal and neonatal health. Nutrients, 15(3), 490.https://doi.org/10.3390/nu15030490

Leite, A. D. S., Chagas, M. S., Silva, R. P. D., et al. (2024). Changes in creatine metabolism during pregnancy: Evidence from a longitudinal study. Nutrients, 16(5), 829.https://doi.org/10.3390/nu16050829

Mayo Clinic. (2024). Prenatal vitamins: Why they matter, how to choose.Retrieved from https://www.mayoclinic.org/healthy-lifestyle/pregnancy-week-by-week/in-depth/prenatal-vitamins/art-20046945

Mountjoy, M., Sundgot-Borgen, J., Burke, L., Ackerman, K. E., Blauwet, C., Constantini, N., Lebrun, C., Lundy, B., Melin, A., Meyer, N. L., Sherman, R., Steffen, K., Budgett, R., & Ljungqvist, A. (2018). The IOC consensus statement on relative energy deficiency in sport (RED-S): 2018 update. British Journal of Sports Medicine, 52(11), 687–697.https://doi.org/10.1136/bjsports-2018-099193

Peart, D. J., Siegler, J. C., & Vince, R. V. (2019). Practical recommendations for coaches and athletes: A meta-analysis of sodium bicarbonate use for high-intensity performance. Journal of Strength and Conditioning Research, 33(1), 56–67.https://doi.org/10.1519/JSC.0000000000002601

Thomas, D. T., Erdman, K. A., & Burke, L. M. (2016). Position of the Academy of Nutrition and Dietetics, Dietitians of Canada, and the American College of Sports Medicine: Nutrition and athletic performance. Journal of the Academy of Nutrition and Dietetics, 116(3), 501–528.https://doi.org/10.1016/j.jand.2015.12.006