– Written by Jenna Schulz, Chloe Hewitt, Jane Thornton, Canada

INTRODUCTION

Nia Ali. Shelly-Ann Fraser-Pryce. Faith Kipyegon. Besides breaking records, these World Champion women are a few of the growing number of female athletes that are returning to elite level competition postpartum. Of the top 150 ranked female marathoners of all time, 25% are mothers, the majority having had one child during their career¹. Until recently, it was generally accepted that women had to choose between sport participation and starting a family^2-4. A 2023 study of elite female runners who were planning to become pregnant reported that 60% intended to resume competing postpartum⁵. While an increasing number of athletes are extending their career into motherhood, many data gaps exist and new data surrounding pregnancy and the postpartum period in sport are continually emerging.

Studies on pregnancy and postpartum experiences in Athletics are generally positive. Injury rate is relatively low during pregnancy for competitive runners (3.9%)⁶. For athletes who returned to sport post-pregnancy, 56% reported an improved performance⁵. Common themes that promote return to sport include support (i.e. familial, spousal, financial)^2,5, and athlete-mother identity^4,6.

Evidence-based advice for athletes, coaches and medical staff are crucial, as are well-defined and supportive policies from sporting organizations and sponsors. The aim of this article is to outline physiological changes, address data gaps and improve direction for athletes, coaches and medical staff, to help keep athlete-mothers in sport longer.

Menstrual Cycle and Performance

The menstrual cycle is the body’s way of preparing for pregnancy. Once established, a regular menstrual cycle lasts an average of 21-35 days and involves fluctuating levels of estrogen and progesterone. While the main purpose of estrogen and progesterone is for reproduction, these hormones also affect other bodily functions^3,8. Menstrual cycle phase is associated with changes in sport and exercise performance. However, data on this topic are scarce, predominately of low-moderate quality, and contradictory⁷. For example, some athletes report decreased performance during the early follicular and late luteal phases⁷ while running economy may differ at high intensities in the mid-luteal⁸ or follicular phase⁹. A large systematic review has concluded that although exercise performance may be trivially reduced in the early follicular phase, there was large between-study variation and individual variations may exist¹⁰. Menstrual cycle disturbances such as oligomenorrhea and amenorrhea are also common among endurance athletes due to energy imbalance associated with high training demands, and may result in increased rates of injury and illness and reduced performance^3,11. Long term effects of menstrual cycle disturbances on reproductive health and later fertility are currently unknown.

Training During Pregnancy

Pregnancy Planning

Athletes have unique considerations with respect to the planning and process of conceiving. When planning pregnancy, athletes report doing so within the first two years of an Olympic cycle to allow them enough time to conceive, deliver a child, and return to peak performance¹². In one study, distance runners reported conceiving during reduced training loads, with a considerable proportion intentionally training less to increase their chances of pregnancy. This training compromise often resulted in athletes’ concerns for its impact on athletic performance, given expectations from sponsors or sport organizations⁵. In another study, several elite distance runners revealed that they timed pregnancy around racing schedules, so as not to miss major competitions in which they would be paid by their sponsors to participate¹³. Supportive and flexible policies around training and racing schedules to accommodate optimal health and performance of athlete-mothers are key.

Training Guidelines

The World Health Organization (WHO) recommendations for physical activity throughout pregnancy suggest all pregnant women without contraindication should partake in a weekly minimum of 150 minutes of moderate intensity exercise, over a span of at least three days¹⁴. Elite athletes - especially runners - report a sense of uncertainty around training through pregnancy¹⁵. A previous study has demonstrated that training advice received by competitive pregnant athletes were relatively conservative suggesting that they keep their heart rate (HR) below 140 beats per minute (bpm)¹⁶. Other recent guidelines allow for a higher cutoff – equal to or greater than 160 bpm or 90% of maximum rate of oxygen consumption during exercise (VO₂ max)¹¹. The majority of these exercise guidelines are tailored towards the general population who partake in short periods of moderate intensity exercise¹⁷. Athletes exercise well above the 150 minutes/week recommendation, and often at vigorous intensity (exceeding 80-90% of HRmax), causing some to question the relevance of recommendations to their situation¹⁵.  For example, elite athletes report undertaking 3-4x the recommended 150 minutes/week during the third trimester^18,19. In a study of 42 elite runners, most reported running volume decreased significantly from the first to third trimester, and average training pace was slower; however, training volumes were still 2-4 times greater than current guidelines⁵. Researchers recently demonstrated that high intensity interval training (HIIT) at >90% of HRmax was well tolerated by both mother and fetus,²⁰ indicating that guidance may still be relatively conservative for trained athletes.

The International Olympic Committee (IOC) published a summary of research in 2016 on exercise during pregnancy in recreational and elite-level athletes. This was the first set of recommendations tailored specifically to athletes. Without contraindications (e.g., pre-eclampsia, hypertension), women may be safely advised to continue with their regular aerobic activity, while monitoring for important symptoms (e.g. vaginal bleeding, frequent contractions)¹¹.

Training Postpartum

Traditional return to sport frameworks after musculoskeletal injury or surgery involve assessing both physical and mental readiness. Managing postpartum return to sport can be thought of in a similar manner. When managing and evaluating return to running readiness, a whole-systems, biopsychosocial approach (i.e. physical deconditioning, changes to body mass, sleep, breastfeeding, relative energy deficiency in sport (REDs), postpartum fatigue and thyroid autoimmunity, fear of movement, psychological well-being and socioeconomic considerations) should be considered²¹. To date, women are often given the green light to return to activity and progress to return to sport as early as six weeks postpartum, despite substantial physical and physiological changes that affect nearly every system in the body²². Once athletes receive medical clearance to resume training, they report being left without direction for training decisions³.

A gradual return to physical activity is strongly encouraged to allow the body to recover from childbirth and minimize complications^23-26. Some use the establishment of good abdominal muscle and pelvic floor engagement as a benchmark^27,28. Other factors to consider are energy levels, sleep quality, level of trauma from childbirth, as well as menstrual, breast and mental health^21,25,29. Low-impact sports such as cycling and swimming may be resumed at a low intensity shortly after childbirth. Strength training may be reintroduced when core stability is established, and initial training should emphasize pelvic floor exercise^24,25,29. Due to the higher impact of running, a walk-jog program is recommended upon return, beginning with more walking than running. While some athletes may begin running as early as one week postpartum, recommendations suggest waiting 12 weeks, especially those who have undergone a cesarean section^30-32. Christopher et al. (2022) describe the four-phase approach, which outlines screening (i.e. pelvic health, impact readiness, physiological variables), a gait analysis and framework that begins with strength training and a walk-run program²⁹. Goom et al. (2019) developed a substantial framework to assist professionals in providing advice for return to running postpartum³³. However, guidelines may differ for elite athletes.

Health Outcomes

Pregnancy and Childbirth Outcomes

Regular aerobic exercise has been associated with a reduced risk of pre-eclampsia and gestational diabetes compared to remaining sedentary while pregnant³⁴. Previous concerns of higher risk of pregnancy loss due to high-intensity exercise have been disproven¹⁷. Additionally, birthweight of athletes’ babies do not differ compared to non-athletes^17,35,36.

An exception is made regarding outcomes for pregnant athletes with eating disorders, who have an increased risk of excessive nausea and vomiting, anemia, vaginal bleeding, hypertension, spontaneous abortion, and preterm birth and should be managed/monitored accordingly¹¹.

Postpartum Outcomes

Despite the commonly held belief that incontinence in postpartum athletes is more common due to increased strain on the pelvic floor, no studies have detected an association between elite sport participation and both urinary and anal incontinence^17,27,35-37. Pelvic floor training during pregnancy can effectively treat and prevent incontinence as well as pelvic organ prolapse^24,27.

Injury/Pain

In a study of 42 elite distance runners, half reported postpartum injuries that interrupted their return to performance, including bone stress, musculoskeletal and nerve injuries⁵. The sacrum, while an uncommon region for bone stress injury in nulliparous athletes, is more commonly affected among postpartum athletes^5,18,19,37. Hormonal changes during pregnancy and breastfeeding, particularly in relaxin, increase joint laxity, resulting in an increased risk for strains and sprains^36,37.

Athletes may be at an increased risk for low back and pelvic girdle pain due to stress and loading of the lumbopelvic region. Low back and pelvic girdle pain are also common postpartum^27,35,38. However, the risks of injury can be mitigated with proper guidance on return to sport.

Breastfeeding

As many as 88% of elite athletes report to have breastfed^18,24. Most do so for a minimum of six months and average of nine to ten months^18,35,39, and most were able to train for their sport at the same time^24,40,41. However, in a qualitative analysis of 14 elite distance runners, breastfeeding was identified as a barrier to training and competition. Limited access to relevant breastfeeding information and concerns for baby’s health were common themes as well³⁹. Athletes discussed the need to plan their training sessions around feeding to avoid the discomfort of exercising with full breasts³. While the impact of training on the ability to breastfeed seems to vary across individuals, regular exercise does not appear to negatively impact the quantity or quality of milk produced^3,36.

In addition, several diagnostic factors associated with Relative Energy Deficiency in Sport (REDs) may be confounded by lactation, for instance dietary restriction, sleep disturbances, oligomenorrhea/amenorrhea and bone stress injuries^21,42. Changes in endocrine function and increased caloric need may increase a lactating athlete’s risk of developing REDs⁴². Exposure to low energy availability may negatively influence lactation²⁴. Therefore, clinicians should be aware of and advise postpartum athletes regarding returning to unaccustomed running volume/intensity and/or having low energy from high physical demands, breastfeeding, nutritional deficiencies and/or sleep deprivation²¹.

Psychological Outcomes

 Elite athletes may experience a wide variety of psychological effects during their return to sport. Initial feelings may include guilt, stress and uncertainty as they navigate this new journey. However, as athletes adjust to their new dual identity, they commonly gain a sense of pride, motivation, resilience and newfound enjoyment for their sport. Most athletes seem to have more positive attitudes and satisfaction upon being a mother^2,6,43-45. Several athlete-mothers expressed the need to be a positive role model for their children, demonstrating that women can have flourishing careers in addition to being a good mother⁴³. Their children provide strong motivation to succeed both on and off the field of play^2,6,43-45. Parental leave left many individuals missing their sport and were therefore very enthusiastic to resume training⁴³. Others found this enjoyment from viewing their training as a break from the demands of motherhood for some personal time⁴⁴. Assuring adequate financial supports can also have beneficial psychological effects, as it may take away pressure from sponsors to make a premature return⁴⁵.

Performance Outcomes

Return to Competition

Postpartum competition schedules vary considerably. For instance, one study reported  intervals prior to return to racing ranging from 9-94 months¹. In another study, elite runners reported an average of two to three races in the year following pregnancy. This increased after three to five years, however the runners still competed significantly less than pre-pregnancy⁵. Differences among level of physical demand, priorities, advice provided and supports in place may account for some of the changes.

Postpartum Performance

A systematic review of studies of postpartum elite athletes detected (with very low certainty evidence) no association between pregnancy and decreased postpartum performance, and even potentially improved performance³⁷. Several studies revealed that over half returned to at least their pre-pregnancy performance level, with some able to return to this level as early as three to nine months postpartum. The proportion of athletes with improved postpartum performances ranged from 11 to 90%^18,35,46.

There are several biological changes that occur throughout pregnancy that can contribute to improved performance. During pregnancy and continuing into the postpartum period, the heart can carry a larger volume of blood as a result of increased chamber capacities. Maximal aerobic capacity or VO₂max - a commonly used measurement of fitness among endurance sports - may decrease in the first six weeks postpartum, but thiswill usually return to or even increase from pre-pregnancy values by 12 weeks postpartum^36,40,47. 

 Several studies have evaluated the postpartum performance of distance runners in particular. A considerable number of runners posted improved performance in motherhood, and those that did not either returned to their pre-pregnancy performance level or saw only a small decrease^1,5. One study demonstrated that runners who gave birth younger than the estimated peak performance age had their top performance during motherhood, while those who became mothers after reaching the peak performance age experienced their top performances prior to motherhood¹. This suggests that for distance running, age may be a more significant factor in determining peak athletic performance than pregnancy. These findings may not be generalizable to all postpartum athletes.

Finally, many postpartum athletes report improved mental performance as a result of motherhood. Improvements such as more enjoyment of their sport, less pressure to perform, and more dedication to balance sport and motherhood have often been accompanied by enhanced physical performance. Athletes who were able to find a balance between motherhood and sport described a reciprocal relationship between the two roles².

CONCLUSION

Evidence from recent World Championships and existing literature show that it is feasible not only to return to competition but excel after pregnancy. Athlete mothers are making great strides and changing the narrative surrounding postpartum return to sport. It is important as clinicians, coaches, sport organizations and researchers that we continue to develop guidelines to aid in the return to sport process and provide a welcoming and supportive environment for these athletes to excel. If we are better able to support our athletes, then the likelihood of returning to competition postpartum will become more of the norm.

References

1. Forstmann N, Meignié A, De Larochelambert Q, et al. Does maternity during sports career jeopardize future athletic success in elite marathon runners? Eur J Sport Sci 2023; 23: 896–903.
2. Darroch F, Hillsburg H. Keeping pace: Mother versus athlete identity among elite long distance runners. Womens Stud Int Forum 2017; 62: 61–68.
3. Davenport MH, Ray L, Nesdoly A, et al. We’re not Superhuman, We’re Human: A Qualitative Description of Elite Athletes’ Experiences of Return to Sport After Childbirth. Sports Medicine 2022; 53: 269–279.
4. Mcgannon KR, Curtin K, Schinke RJ, et al. (De)Constructing Paula Radcliffe: Exploring media representations of elite running, pregnancy and motherhood through cultural sport psychology. Psychol Sport Exerc 2012; 13: 820–829.
5. Darroch F, Schneeberg AMY, Brodie R, et al. Effect of Pregnancy in 42 Elite to World-Class Runners on Training and Performance Outcomes. Med Sci Sports Exerc 2023; 55: 93–100.
6. Massey KL, Whitehead AE. Pregnancy and Motherhood in Elite Sport: The Longitudinal Experiences of two Elite Athletes. Psychol Sport Exerc 2022; 60: 1–10.
7. Carmichael MA, Thomson RL, Moran LJ, et al. The impact of menstrual cycle phase on athletes’ performance: a narrative review. International Journal of Environmental Research and Public Health 2021; 18: 1–24.
8. Goldsmith E, Glaister M. The effect of the menstrual cycle on running economy. Journal of Sports Medicine and Physical Fitness 2020; 60: 610–617.
9. Dokumacı B, Hazır T. Effects of the Menstrual Cycle on Running Economy: Oxygen Cost Versus Caloric Cost. Exercise and Sport 2019; 90: 318–326.
10.  McNulty KL, Elliott-Sale KJ, Dolan E, et al. The Effects of Menstrual Cycle Phase on Exercise Performance in Eumenorrheic Women: A Systematic Review and Meta-Analysis. Sports Medicine 2020; 50: 1813–1827.
11.  Bø K, Artal R, Barakat R, et al. Exercise and pregnancy in recreational and elite athletes: 2016 evidence summary from the IOC expert group meeting, Lausanne. Part 1—exercise in women planning pregnancy and those who are pregnant. Br J Sports Med 2016; 50: 571–589.
12.  Pullen E, Miller B, Plateau C. Experiences of Pregnancy in Elite Female Athletes on the World Class Programme. Loughborough, UK, June 2021.
13.  Darroch FE, Giles AR, Hillsburg H, et al. Running from responsibility: athletic governing bodies, corporate sponsors, and the failure to support pregnant and postpartum elite female distance runners. Sport Soc 2019; 22: 2141–2160.
14.  World Health Organization. WHO guidelines on physical activity and sedentary behaviour. 2020.
15.  Davenport MH, Nesdoly A, Ray L, et al. Pushing for change: a qualitative study of the experiences of elite athletes during pregnancy. Br J Sports Med 2022; 56: 452–457.
16.  Beilock SL, Feltz DL, Pivarnik JM. Training Patterns of Athletes during Pregnancy and Postpartum. Res Q Exerc Sport 2001; 72: 39–46.
17.  Wowdzia JB, McHugh TL, Thornton J, et al. Elite Athletes and Pregnancy Outcomes: A Systematic Review and Meta-analysis. Med Sci Sports Exerc 2021; 53: 534–542.
18.  Sundgot-Borgen J, Sundgot-Borgen C, Myklebust G, et al. Elite athletes get pregnant, have healthy babies and return to sport early postpartum. BMJ Open Sport Exerc Med 2019; 5: 1–9.
19.  Mourot L, González-Alonso J, Solli GS, et al. Training Characteristics During Pregnancy and Postpartum in the World’s Most Successful Cross Country Skier. Front Physiol 2018; 9: 1–9.
20.  Wowdzia JB, Tom ·, Hazell J, et al. Maternal and Fetal Cardiovascular Responses to Acute High-Intensity Interval and Moderate-Intensity Continuous Training Exercise During Pregnancy: A Randomized Crossover Trial. Sports Medicine 2023; 53: 1819–1833.
21.  Donnelly GM, Brockwell E, Rankin A, et al. Beyond the Musculoskeletal System: Considering Whole-Systems Readiness for Running Postpartum. J Womens Health Phys Therap 2022; 46: 48–56.
22.  Soma-Pillay P, Nelson-Piercy C, Tolppanen H, et al. Physiological changes in pregnancy. Cardiovasc J Afr 2016; 27: 89–94.
23.  Artal R, O’Toole M. Guidelines of the American College of Obstetricians and Gynecologists for exercise during pregnancy and the postpartum period. Br J Sports Med 2003; 37: 6–12.
24.  Bø K, Artal R, Barakat R, et al. Exercise and pregnancy in recreational and elite athletes: 2016/17 evidence summary from the IOC Expert Group Meeting, Lausanne. Part 3 - Exercise in the postpartum period. Br J Sports Med 2017; 51: 1516–1525.
25.  Donnelly G, Moore I, Brockwell E, et al. Reframing return-to-sport postpartum: the 6 Rs framework. Br J Sports Med 2022; 56: 241–248.
26.  Deering RE, Christopher SM, Heiderscheit BC. From childbirth to the starting blocks: Are we providing the best care to our postpartum athletes? Journal of Orthopaedic and Sports Physical Therapy 2020; 50: 281–284.
27.  Bø K, Artal R, Barakat R, et al. Exercise and pregnancy in recreational and elite athletes: 2016/2017 evidence summary from the IOC expert group meeting, Lausanne. Part 5. Recommendations for health professionals and active women. Br J Sports Med 2018; 52: 1080–1085.
28.  Thein-Nissenbaum J. The postpartum triathlete. Physical Therapy in Sport 2016; 21: 95–106.
29.  Christopher SM, Gallagher S, Olson A, et al. Rehabilitation of the Postpartum Runner: A 4-Phase Approach. J Womens Health Phys Therap 2022; 46: 73–86.
30.  Donnelly GM, Rankin A, Mills H, et al. Infographic. Guidance for medical, health and fitness professionals to support women in returning to running postnatally. Br J Sports Med 2020; 54: 1114–1115.
31.  Inge P, Orchard JJ, Purdue R, et al. Exercise after pregnancy. AJGP 2022; 51: 117–121.
32.  Lee R, Thain S, Tan LK, et al. Asia-Pacific consensus on physical activity and exercise in pregnancy and the postpartum period. BMJ Open Sport Exerc Med; 7. Epub ahead of print 17 May 2021. DOI: 10.1136/bmjsem-2020-000967.
33.  Donnelly G, Brockwell E, Goom T. Return to running postnatal - guideline for medical, health and fitness professionals managing this population. Physiotherapy 2020; 107: e188–e189.
34.  De Borja C, Chang CJ, Watkins R, et al. Optimizing Health and Athletic Performance for Women. Curr Rev Musculoskelet Med 2022; 15: 10–20.
35.  Bø K, Backe-Hansen KL. Do elite athletes experience low back, pelvic girdle and pelvic floor complaints during and after pregnancy? Scand J Med Sci Sports 2007; 17: 480–487.
36.               L’Heveder A, Chan M, Mitra A, et al. Sports Obstetrics: Implications of Pregnancy in Elite Sportswomen, a Narrative Review. J Clin Med; 11. Epub ahead of print 1 September 2022. DOI: 10.3390/jcm11174977.
37.  Kimber ML, Meyer S, McHugh TL, et al. Health Outcomes after Pregnancy in Elite Athletes: A Systematic Review and Meta-analysis. Medicine and Science in Sports and Exercise 2021; 53: 1739–1747.
38.  Nose-Ogura S. Advancement in female sports medicine and preventive medicine. Journal of Obstetrics and Gynaecology Research 2021; 47: 476–485.
39.  Giles AR, Phillipps B, Darroch FE, et al. Elite Distance Runners and Breastfeeding. Journal of Human Lactation 2016; 32: 627–632.
40.  Potteiger J, Welch J, Byrne J. From parturition to marathon: a 16-wk study of an elite runner. Med Sci Sports Exerc 1993; 25: 673–677.
41.  Tenforde AS, Toth KES, Langen E, et al. Running Habits of Competitive Runners During Pregnancy and Breastfeeding. Sports Health 2015; 7: 172–176.
42.  Deering RE, Mountjoy ML. REDs and the lactating athlete: an evidence gap. Br J Sports Med 2023; 57: 1065–1066.
43.  Appleby KM, Fisher LA. “Running in and out of Motherhood”: Elite Distance Runners’ Experiences of Returning to Competition after Pregnancy. Women Sport Phys Act J 2009; 18: 3–17.
44.  Palmer FR, Leberman SI. Elite athletes as mothers: Managing multiple identities. Sport Management Review 2009; 12: 241–254.
45.  Joel Tighe B, Williams SL, Porter C, et al. Barriers and enablers influencing female athlete return-to-sport postpartum: a scoping review. Br J Sports Med 2023; 0: 1–8.
46.  Penttinen J, Erkkola R. Pregnancy in endurance athletes. Scand J Med Sci Sports 1997; 7: 226–228.
47.  Almquist NW, Sandbakk Ø, Solli GS. Performance-Related Physiological and Haematological Changes During Pregnancy and Postpartum in a Well-Trained Cyclist Performing Endurance Training. Front Physiol 2022; 13: 762950.

 Header image by RUN 4 FFWPU (Cropped)