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Pregnancy Considerations for the Active Individual

Kayla Causey, Sammi Iannucci, and Sarah McClellen

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Learning Objectives

Learner will appreciate the physiologic adaptations throughout pregnancy.
Learner will understand general safety limits of exercise for each trimester in a normal, healthy pregnant individual.
Learner will be able to list contraindicated treatment techniques as well as know when to stop activities.
Learner will identify benefits of aerobic and resistance training during pregnancy.
Learner will be able to provide practical recommendations for women who wish to continue running or training during pregnancy.

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Why should we consider this? (Barakat 2010, ACOG 2020)

Only 20% of healthy pregnant women meet activity recommendations.

Exercise during pregnancy is safe, beneficial, and encouraged

We need to be able to answer our patients’ questions

51% of women sought information from their PT (Prevett 2023)

For our higher performing athletes:

Return to sport / recover from physiologic changes more quickly

https://www.washingtonpost.com/sports/olympics/interactive/2021/olympics-mothers/

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Physiologic Changes

Musculoskeletal (ACOG 2020, Carmichael 2021)

Center of gravity, gait changes, relaxin

Cardiovascular (Carmichael 2021, Melzer 2010)

Increased blood volume, heart rate, preload, afterload

Respiratory (Carmichael 2021, Melzer 2010)

50% increased minute ventilation
Reduced pulmonary reserve → reduced and lagged anaerobic capabilities
Elevated diaphragm

Metabolic (Carmichael 2021, ACOG 2020, Milunsky 2002)

Enhanced blood glucose drops during exercise
Suggested increase of carbohydrate intake
Reduced temperature regulatory abilities → proper hydration

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General Contraindications

Consult with doctor: vaginal bleeding, dizziness, lightheadedness, dyspnea, racing heart rate, chest pain, unusual pains, limited movement of fetus (ACOG 2020)
Avoid activities with contact sports and activities with high risk of falls
Caution with altitude training (Huch 1996, Hinman 2015)

Above 8250 feet without 4-5 days of acclimation
Increased risk of fetal hypoxemia

Avoid scuba diving (Hinman 2015)

Fetus not protected from decompression sickness and gas embolism

Avoid exercise in hot, humid environments (Melzer 2010, Selman 2022)

Increased risk for neural tube defects during 1st trimester

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Contraindications to Exercise (Ribeiro 2019)

Absolute Contraindications

Ruptured membranes
Premature labor
Unexplained persistent vaginal bleeding
Placenta previa after 28 weeks
Pulmonary Embolism
Incompetent cervix
Intrauterine growth restriction
High-order multiple pregnancy (ex. triplets)
Uncontrolled Type 1 DM
Uncontrolled hypertension
Uncontrolled thyroid disease
Respiratory or systemic disorders

Relative Contraindications

Recurrent pregnancy loss
History of spontaneous preterm birth
Twin pregnancy after 28th week
Mild/moderate cardiovascular or respiratory disease
Symptomatic anemia
Malnutrition
Eating disorders

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Benefits of Exercise

Decreased incidence of (Ribeiro 2021)

Gestational diabetes
Hypertensive disorders
Operative deliveries
Excess weight gain
Weight retention postpartum
Postpartum depression
Preterm birth
Musculoskeletal discomfort (Melzer 2010)
WB exercise can improve work efficiency (Melzer 2010)

Improved cardiovascular function (Melzer 2010)

https://www.womensrunning.com/culture/alysia-montano-usa-champioknships-pregnant/

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Trimester Considerations

1st trimester (Weeks 1 - 12)

Avoid exposure in excessive heat (Milunsky 2022)
Prevalence of nausea, fatigue, discomfort (Selman 2022)
Begin deep core and pelvic floor exercises

2nd trimester (Weeks 12 - 26)

Increased weight gain and greater changes in center of gravity
Caution with prolonged supine exercise supine after 20 weeks (ACOG 2020, Hinman 2015)
May need to substitute dumbbells for barbell (Selman 2022)

3rd trimester (Weeks 27 - birth)

Continue to monitor symptoms during exercise
May need to increased rest times (Selman 2022)
Intensity of exercise will most likely decrease due to:

Center of gravity changes
Increased joint laxity
Discomfort
Increased load on pelvic floor muscles

1st trimester

Exposure to excessive heat

Risk of neural tube defect → as mentioned previously

Morning sickness → will be biggest limator in exercise regimen

2nd Trimester (13-26 weeks)

Use of pelvic belts and core stability exercises can be helpful to continue being able to exercise (Melzer 2010)
Prolonged supine exercise: supine positioning may result in decreased venous return due to aortocaval compression → hypotension, avoid supine exercise (ACOG, 2020)

quadirep is good position to do strengthening exercises in instead

Eliminate barbell over abdomen

Due to greater changes in size of stomach → exercises with barbell resting on the pelvis (hip thrust) and barbell overhead (overhead press) may be uncomfortable or cause individual to use altered mechanics to get bar overhead

Plyometrics

Listen to your body, can make modifications
Increased laxity, weight gain, and changes in COG → may make it more difficult to maintain balance

3rd trimester

Monitor symptoms

Communicate to medical providers the presence of abnormal symptoms or changes in body’s response to exercise
Increased rest times

Due to increase cardiovascular demands and increased load on pelvic floor

Postural control/stability

Breath work, coordination of pelvic floor muscles
Postural endurance: thoracic extensors, thoracic rotators, transversus abdominis, obliques, hip flexors, hip extensors
Ex. Pallof press, glute bridge, bird dog, single sided carry, deep breathing

Limit lumbar flexion

Due to changes in abdomen

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Sport and Activity-Specific Implications

LonnaeONeal. Natasha Hastings runs down the obstacles of being a pregnant olympic hopeful. Andscape. https://andscape.com/features/natasha-hastings-runs-down-the-obstacles-of-being-a-pregnant-olympic-hopeful/. Published May 30, 2019.

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General Considerations for the Active Individual

In general: vigorous intensity exercise into the 3rd trimester is safe for most healthy pregnancies.

No higher than 90% HRM (Salvesen 2021)
RPE 12-14 (Evenson 2021)
“Talk Test” to measure exercise intensity (ACOG 2020)
Maintain appropriate hydration to prevent hyperthermia (Bo et al. 2016, ACOG 2020)
Maintain appropriate caloric intake especially carbs around exercise (Carmichael 2021)
Consider pre pregnancy fitness level and intensity of exercise

Salvesen - Study performed looking at uteroplacental blood flow during strenuous treadmill running in the 2nd trimester. 6 olympic level athletes age 28-37 training 15-22 h per week. Women ran 3-5 submax workloads on treadmill with 60-90% max o2 consumption. Circulation assessed using doppler ultrasound of uterine and umbilical arteries before, during, and after exercise. Mean uterine artery volume BF was reduced to 60-80% after warming up and stayed at 40-75% of initial value during exercise. Fetal HR was within normal ranges (110-160 bpm) if woman stayed below 90% of max heart rate. Going over 90% caused fetal bradycardia in some cases, an abnormal response.
Even greater blood glucose drops with exercise and maternal glucose is fetus’s main source of energy
Previous thinking was don’t do anything during pregnancy you haven’t done before, but many previously sedentary women may have a renewed interest in becoming more active and improving their health and that of their baby

It is now encouraged as long as its progressive as any exercise plan would be for a sedentary person
There are even some things you should add into your physical activity that you haven’t focused on with workouts before such as core work to minimize ab separation, the TA in particular is good to learn how to activate it now and not after pregnancy, also learning to properly brace spine helps with postural changes

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(Bo et al. 2016)

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Running Considerations

Cardiovascular (Salvesen et al. 2012)

Keep HR <90% max
Avoid high intensity runs at altitude

Thermoregulation (Bo et al. 2016)

60%–70% of VO2max to keep core temp from raising > 103°F
Hydration, avoid direct sun, avoid blacktop, light loose clothing

Metabolical (Carmichael 2021)

Make sure adequate carb intake is being met

Musculoskeletal (Carmichael 2021) (Bo et al. 2016)

Repetitive nature and heavy impact of running combined with postural changes and joint laxity may cause increased discomfort especially in 3rd trimester
Changes to gait including decreased step length, increased double support time, and wider stance
Running on a slight incline which encourages a forward lean improves lordosis

https://www.runnersworld.com/training/a20849722/what-you-need-to-know-about-running-and-pregnancy/ (runnersworld.com)

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Managing Running Expectations (Bo et al. 2016)

Most runners decrease training volume and fewer than ⅓ continue into 3rd trimester
Goal of fitness maintenance and not setting PRs or marathon training
Using RPE/HR/talk test and not mileage/speed
Expectations each trimester

1st - increased fatigue, body is adapting
2nd - best time to moderately challenge the body
3rd - increased discomfort due to postural changes,

larger demand on hips and knees with weight gain, and

laxity is greatest, Braxton Hicks contractions

https://www.bing.com/images/search?view

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Resistance Training in Pregnancy

Few studies have been performed at high % RM and heavy weight

Prevett et al (2023): Survey-based study of 679 women who lifted ≥80% 1RM

Most adjusted/modified weight around 28-30 weeks (~60% 1RM)
Delivery complications not affected between-groups by presence of

Supine lifts (71% engaged in)
Valsalva (34% engaged in)
Olympic lifts (72% engaged in)

What does this tell us?

Perhaps, we are being too cautious.

Perhaps, no one wants to advise incorrectly.

Definitely, we need more research.

https://www.telegraph.co.uk/weightlifting/2021/02/26/top-athletes-keeping-careers-track-pregnancy/

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Approaching the Valsalva Maneuver and Supine Lifting

Valsalva “flagged” for concern but not proven

Concern for decrease in maternal BP affecting fetal blood flow (Pivarnik 2016)
Valsalva medical ≠ valsalva weightlifting
Modification: free-breathing through press, especially later in pregnancy

Two additional studies disprove a harmful reaction (Meah 2021, Gould 2021)

Limitations exist in % 1RM and population

Supine Lifting (Prevett 2023, ACOG 2020, Hinman 2015)

Symptomatic supine lifting needs modification
No supine lifting in 3rd trimester
Further research and guidelines also being explored

https://blogs.lt.vt.edu/zcornwel/2014/03/05/baby-shaming/

Valsalva and Supine lifting are both relatively controversial due to possible concerns to fetus and mom.

Medical valsalva - or close glottis bearing down, involves relaxation of the pelvic floor. Commonly used for assessing prolapse, cardiac condition assessment, and birthing
Weightlifting valsalva - involves a drawing up through the pelvic floor (kegel) which also limits stress on the pelvic floor and limits stress incontinence. We should be educating our resistance training women (pregnant AND not) how to perform this type of valsalva. This will also help to reduce incontinence.
There is a time and a place for teaching the valsalva with a relaxed pelvic floor and this might come later close to the delivery process.
We still need more objective data on what happens at these high percent RMs

Modifications to the valsalva might need to be made later in pregnancy when it becomes harder to perform this maneuver. This can be done with free-breathing or steady exhale through the press movement.

Two other studies disprove a harmful reaction - however these studies might not have been completely representative a resistance of the response that we want to look at.

Mesh 2021 study: unfortunately, this study utilized a 40% 10 rep max load - which averaged ~100 pounds on the leg press. This is not typically the range that our athletes will be working in.

Gould 2021 study: showed that use of valsalva does not decrease placental BF in a semi-reclined 1RM Bench press. Unfortunately, the population was not representative of our higher performing athletes. Weights were capped in the study at 50#. Was it truly a 1RM? We don’t know.

Supine Lifting:

Symptomatic supine positioning through the first and second trimesters DOES indicate a change in blood flow, so we definitely need to consider modifications

Due to the increasing size and weight of the baby, modifications definitely elicited in 3rd trimester (we can coach on semi-reclined positioning OR machines that achieve similar work to the muscle group)

This area of research also being challenged.

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Resistance Training: Other PT Implications

Pain (ACOG 2020)

Musculoskeletal changes
Lower resistance, focus on form, reduce overhead lifting

Form (Selman 2022)
Check barbell form as to not put pressure on abdomen (olympic lifts, hip thrusts)
Less core engagement as pregnancy progresses

Intensity (Salvesen 2012)

< 90% HR max so as to not compromise fetal BF

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Multidisciplinary Team

OB
Pelvic floor PT
Dietician
Psychologist - general, sport psychologist
Primary Care Provider
Coach/Trainer

Athletic Trainer
Strength/Conditioning Coach
Personal trainer
Recreational coach - (e.g. CrossFit)

https://www.theguardian.com/sport/2022/may/18/im-a-pregnant-woman-making-choices-shauna-coxsey-on-climbing-and-the-bullies-who-want-her-to-stop

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Clinician Resources

American College of Obstetrics and Gynecology Guidelines: Physical Activity and Exercise During Pregnancy and the Postpartum Period: ACOG Committee Opinion, Number 804 - PubMed (nih.gov)

Clinical Guideline

Running In Pregnancy - Webinar from the American Academy of Sports PT given by Carey Rothschild (must be a member of AASPT)

Expert opinion with analysis of RCTs

Pregnant & Postpartum Running with Dr. Rachel Selman DPT, CSCS - Episode from the Strength Running Podcast

Expert opinion

Heavy Resistance Podcast with Dr. Christina Prevett, PT PhD - Episode from The Pelvic Health Podcast

Expert opinion with research overview

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References

Barakat R, Refoyo I, Coteron J, Franco E. Exercise during pregnancy has a preventative effect on excessive maternal weight gain and gestational diabetes. A randomized controlled trial. Braz J Phys Ther. 2019;23(2):148-155. doi:10.1016/j.bjpt.2018.11.005
American College of Obstetrics and Gynecologists.Physical Activity and Exercise During Pregnancy and the Postpartum Period: ACOG Committee Opinion, Number 804. Obstet Gynecol. 2020;135(4):e178-e188. doi:10.1097/AOG.0000000000003772
Prevett C, Kimber ML, Forner L, de Vivo M, Davenport MH. Impact of heavy resistance training on pregnancy and postpartum health outcomes. Int Urogynecol J. 2023;34(2):405-411. doi:10.1007/s00192-022-05393-1
Carmichael RD. Considerations for the Pregnant Endurance Athlete. Strength and Conditioning Journal. 2021;43(6):35-41. doi:https://doi.org/10.1519/SSC.0000000000000655
Melzer K, Schutz Y, Boulvain M, Kayser B. Physical activity and pregnancy: cardiovascular adaptations, recommendations and pregnancy outcomes. Sports Med. 2010;40(6):493-507. doi:10.2165/11532290-000000000-00000
Milunsky A, Ulcickas M, Rothman KJ, Willett W, Jick SS, Jick H. Maternal heat exposure and neural tube defects. JAMA 1992;268:882 –5
Huch R. Physical activity at altitude in pregnancy. Semin Perinatol 1996; 20: 303–14
Hinman SK, Smith KB, Quillen DM, Smith MS. Exercise in Pregnancy: A Clinical Review. Sports Health. 2015;7(6):527-531. doi:10.1177/1941738115599358

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References

Selman R, Early K, Battles B, Seidenburg M, Wendel E, Westerlund S. Maximizing Recovery in the Postpartum Period: A Timeline for Rehabilitation from Pregnancy through Return to Sport. Int J Sports Phys Ther. 2022;17(6):1170-1183. Published 2022 Oct 1. doi:10.26603/001c.37863
Ribeiro MM, Andrade A, Nunes I. Physical exercise in pregnancy: benefits, risks and prescription. J Perinat Med. 2021;50(1):4-17. Published 2021 Sep 6. doi:10.1515/jpm-2021-0315
Evenson KR, Hesketh KR. Monitoring Physical Activity Intensity During Pregnancy. Am J Lifestyle Med. 2021;17(1):18-31. Published 2021 Nov 25. doi:10.1177/15598276211052277
Salvesen KÅ, Hem E, Sundgot-Borgen J. Fetal wellbeing may be compromised during strenuous exercise among pregnant elite athletes. Br J Sports Med. 2012;46(4):279-283. doi:10.1136/bjsm.2010.080259
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. British Journal of Sports Medicine. 2018;52(17):1080-1085. doi:10.1136/bjsports-2018-099351
Pivarnik JM, Szymanski LM, Conway MR. The elite athlete and strenuous exercise in pregnancy. Clin Obstet Gynecol 2016;59(3):613–9.
Meah VL, Strynadka MC, Steinback CD, Davenport MH. Cardiac Responses to Prenatal Resistance Exercise with and without the Valsalva Maneuver. Med Sci Sports Exerc. 2021;53(6):1260-1269. doi:10.1249/MSS.0000000000002577
Gould S, Cawyer C, Dell'Italia L, Harper L, McGwin G, Bamman M. Resistance Training Does Not Decrease Placental Blood Flow During Valsalva Maneuver: A Novel Use of 3D Doppler Power Flow Ultrasonography. Sports Health. 2021;13(5):476-481. doi:10.1177/19417381211000717

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Questions?