Current Guidelines on Training During Pregnancy and the Postpartum Period: Jenny

A few years ago, this picture almost broke the Internet! It sparked huge controversy as people from all over the world offered unsolicited opinions on whether a woman in her third trimester should be exercising in this manner or at this intensity. It seems at this time, on a general scale, people follow one of two trains of thought: either exercise is unsafe during pregnancy, or exercise is essential for a healthy pregnancy. So what does science say? The short of it is, the safety and benefits of exercise during pregnancy depend on the person.

http://bokuman.deviantart.com/art/Most-Fruitful-Yuki-100218181

Lets get the legal stuff out of the way first: this series is NOT a substitute for medical advice; it’s not a green light to go postal and lift cars on your way to work! While I recognize that most expectant mothers and moms have what can be described as 'superhuman capabilities', not ALL exercises are recommended during pregnancy, and not all women will have the same response to training. The best pre-natal training plan is one that is developed and monitored by an interdisciplinary team, with input not only from your physician, but also from your trainer, and most importantly, from yourself!

In 2003, both the American College of Obstetricians and Gynaecologists (ACOG) and the Society of Obstetricians and Gynecologists of Canada (SOGC) created guidelines regarding exercise during pregnancy and the postpartum period.  The major recommendation of each of these guidelines was this:

“All women without contraindications should be encouraged to participate in aerobic and strength-conditioning exercises as part of a healthy lifestyle during pregnancy(1,2).”

Five-time US 800m champion Alysia Montaño; Photo From: theguardian.com

Participation in regular weight bearing exercise during pregnancy has been shown to have numerous positive effects including psychological benefits, improving maternal fitness, restricting weight gain without compromising fetal growth, and hastening postpartum recovery(3). Both the Canadian and American guidelines further suggest that not only may a woman continue to exercise during pregnancy, but she also may BEGIN to exercise during pregnancy, as long as she does so slowly and smartly(1,2). For the previously inactive woman, the 'best' time to begin an exercise program is in the second trimester, once the nausea, vomiting, and fatigue that characterize the first trimester of pregnancy have subsided(2). Aerobic exercise, (read: cardio), should be taken on gradually, beginning with 15 minute sessions of continuous exercise three times per week, slowly increasing to 30 minute sessions, 4 times per week (2). For elite athletes, the SOGC recommends a custom program, with supervision from an obstetric care provider who has an in-depth knowledge of the impact of strenuous exercise on both fetal and maternal outcomes(2). Although Alysia Montano, (pictured above) is unbelievably inspiring, her physical activity regimen will not be ideal for all pregnant women; in general, for previously active women, the SOGC recommends the following with regards to aerobic training during pregnancy:

“Reasonable goals of aerobic conditioning in pregnancy should be to maintain a good fitness level throughout pregnancy, without trying to reach peak fitness, or train for an athletic competition(2)”

Having said all of this, it is important that exercising pregnant women focus on balancing their training with proper nutrition, adequate hydration, and rest; they must also avoid large increases in their body temperature by exercising in loose clothing in a temperature controlled environment (3). Here are some other tips provided in these guidelines to help ensure safe and efficient pre-natal and postpartum training:

Women should choose activities that will minimize the risk of loss of balance and fetal trauma(2,3). As changes occur in weight and weight distribution, coordination and balance may be affected; exercise programs should be modified if they pose a significant risk of abdominal injury or fatigue, such as the removal contact sports, water skiing and scuba diving (3). Bicycle riding should be avoided after the first trimester as a result of changes in balance and risk of falling(3).

Exercising in the supine or prone positions should be avoided after the first trimester (1-3) as compression of the vena cava (a large vessel returning blood to the heart), may be caused by the pregnant uterus. Additionally, the ability to perform abdominal exercises may be impeded by the development of diastasis recti (separation or tearing of the rectus abdominal muscles at their midline junction) and associated abdominal muscle weakness(2).

Exercise intensity should not exceed pre-pregnancy levels(3). Because there are changes in circulation, and consequently heart rate and blood pressure in the pregnant population, exercise intensity should not be regulated by heart rate, but rather by how hard a woman believes she is working; generally, a 'moderate to hard' intensity is safe for women who are accustomed to this level of exercise (3). Tools that can be used to monitor exercise intensity in this manner include the 'talk test' and the Borg Scale for Rating of Perceived Exertion (2). 

Resistance exercise and flexibility training may also be included in the prenatal exercise prescription (1-3). There are certainly some precautions that must be observed here! With regards to resistance exercise, heavy weightlifting, powerlifting and other activities that require straining should be avoided(3). Neither the Valsalva maneuver nor breath holding should be used during pregnancy, nor should any other activities or techniques that result in the 'pressor response' (a quick and large increase in blood pressure) (1-4). General recommendations for resistance training during pregnancy include the following(4):

• Avoid breath holding/Valsalva Manueuvers
• Use weight machines or resistance bands rather than free weights to decrease the risk of injuries caused by changing centre of balance
• Decrease resistance (weights), increase repetitions and use shorter sets
• Focus on maintaining proper form during all lifts!
• Avoid Powerlifting activities

With regards to flexibility training, both the woman and her trainer must be aware of the effects of Relaxin on ligaments and joint laxity. Flexibility training should be very slow and controlled, focusing on joint stability in new found positions (1-4). 

Initiation of pelvic floor exercises in the immediate postpartum period may reduce the risk of future urinary incontinence(2). Returning to exercise postpartum is an extremely individualized issue! There is no definitive period of time that a woman must wait before returning to exercise, however, the decision should be made in consultation with her medical team, considering issues such as the duration and intensity of labour, whether she underwent a cesarian delivery, her activity level pre-pregnancy and prenatally, and how she is recovering post-delivery (4). According to the American College of Obstetricians and Gynaecologists, exercise routines may be resumed gradually as soon as it is physically and medically safe (1). Many women begin to plan their return to exercise with their physician at their 6-week postpartum check-up.

For the breastfeeding new mother, moderate exercise during lactation does not affect the quantity or composition of breast milk, nor does it impact infant growth(2). Mothers who find that their baby does not feed as well immediately post-exercise may consider pumping breast milk pre-exercise, or waiting an hour post-exercise before feeding (2). 

Signs that you should stop exercising and seek medical attention include (1-4):

• Vaginal bleeding
• Dyspnoae (shortness of breath) before exertion
• Cramping
• Dizziness or Significant Nausea
• Headache
• Chest Pain
• Muscle Weakness
• Calf Pain or Swelling (need to rule out thrombophlebitis/blood clots)
• Preterm Labour
• Decreased Fetal Movement
• Amniotic Fluid Leakage
• Persistant Pain
• Chronic Fatigue

Lastly, there are some very stringent....

GUIDELINES ON WHO SHOULD NOT EXERCISE (1,2):

As you read through this article, I'm hoping you gleaned one very important thing: Training during the Pregnancy and Postpartum period, while generally safe, is extremely individualized and complex. Decisions on the frequency, type, intensity, and length of your training sessions should be based on your training history, prenatal health and made with input from a variety of WELL INFORMED sources including your physician, trainer, and yourself! Listening to your body is essential, as is open and honest communication with your healthcare team! Up next, read my close friend Zartaj's personal 'Training for Two' Story! 

1. Artal R, O'Toole, M. Guidelines of the American College of Obstetricians and Gynecologists for exercise during pregnancy and the postpartum period. British Journal of Sports Medicine (2003).

2. Davies Gregory A.L, Wolfe Larry. A, Mottola Michelle. F, MacKinnon Catherine. Joint SOGC/CSEP clinical practice guidelines: exercise in pregnancy and the postpartum period. Canadian Journal of Applied Physiology. 28(3):329-341. (2003)

3. Artal R, Clapp J, Vigil D. ACSM Current comment: exercise during pregnancy. Available at: https://www.acsm.org/docs/current-comments/exerciseduringpregnancy.pdf

4. Pivarnik J, Mudd L. Oh baby! Exercise during pregnancy and the postpartum period. ACSM Health and Fitness Journal. 13(3): 8-13. (2009).