You may be feeling nauseous and lethargic and exercise may be the furthest thought from your mind.   But it is important for both you and your baby.  So when you muster up the energy, I hope this addresses all your questions about exercising throughout your pregnancy.  

It can be overwhelming.    Your relatives, co-workers, and friends all share their unsolicited prenatal advice.   And what you read online conflicts with everyone’s expert opinion.  So who is right?  Your doctor or midwife is the ultimate boss, so make sure to clear any exercise plans by them first.   Sort out the facts from the wives’ tales.  Here are 6 myths and rumors you may be getting bombarded with:

1. “Don’t exercise, you will hurt the baby!”

Says who?!   In a study of almost 1500 US women, the rate of exercise-related injuries during pregnancy was 4.1 per 1,000 exercise hours.  Of these injuries, the majority were bruises or scrapes (55%).  (Evenson, Marshall and Vladitiul 2010).   That gives you some pretty good odds!   You are more likely to hurt yourself by tripping on an uneven sidewalk on your way to the gym.  The American Congress of Obstetricians and Gynecologists (ACOG) formally recommends, “In the absence of either medical or obstetric complications, ≥ thirty minutes of moderate exercise a day on most, if not all, days of the week is recommended for pregnant women.”   And the benefits? The benefits of physical exercise are infinite.  

Exercise during pregnancy can benefit your health in the following ways: 

• Helps reduce backaches, constipation, bloating, and swelling. 
• Helps prevent or manage gestational diabetes.
• Increases your energy and improves your mood.
• Improves your posture. 
• Promotes muscle tone, strength, and endurance. 
• Helps you sleep better.

Not only can exercise help keep you fit during pregnancy and improve your ability to cope with labor, it can also make getting back into shape post-baby much easier.  

A paper by Lehman College Professor Brad Schoenfield details how strength training can benefit pregnant women. Professor Schoenfeld is a specialist in exercise science and a faculty member in the Women’s Health Sciences department.  According to the conclusions he reached after an extensive review of the literature, strength training can reduce the occurrence of gestational diabetes and the severity of both postpartum depression and maternal hypertension while also easing postpartum weight loss.  Other benefits include a 54% reduction in the risk of developing preeclampsia during pregnancy (a disorder that can lead to hypertension,  edema,  and seizures).  

Exercise won’t hurt your  baby.  Quite the contrary!  It may actually help the baby. In a large Scandinavian study with almost 6000 women, sedentary pregnant women were compared with those who participated in more than one type of leisure sports activities.  Active women had a significantly reduced risk of preterm birth. Women who engaged in light physical activity (walking) had a 24% reduced risk of preterm delivery and women who engaged in moderate to heavy activity (sports such as tennis, swimming or weekly running, to competitive sports several times a week) had a 66% reduced risk (Hegaard 2008).

2. “If you have pain while exercising during the beginning of your pregnancy, stop everything because it’s only going to get worse.”

Not necessarily!  Your body changes throughout your pregnancy.  Each week something new happens.  For example, your fluctuating pregnancy hormones may be your worst enemy one week and your best friend the next.  Their role in pregnancy is to prepare your body for the growing baby’s occupancy and delivery.  Your pregnancy hormones allow your ligaments and joints to loosen and expand to make room for your growing uterus and pelvis.  These adaptations facilitate your baby’s descent down the birth canal.  These hormones also allow your blood vessels to widen to accommodate the increased blood flow you and your baby need during pregnancy.  These levels peak during the first fourteen weeks of pregnancy and again at the time of delivery.    

Some women love the effects of their increasing pregnancy hormones and others loathe them.    If you’ve always struggled with poor flexibility and stiffness, you may embrace this newly found mobility.  It is time to move up to the front of your pre-natal yoga class and show off your poses! In contrast, some of you may feel more out of alignment and unstable from the changes in your joint laxity.  You may twist your ankle or throw out your back when your joints are looser.  It will be helpful for you to partake in exercises that work both sides of your body equally, such as walking, running, cycling, or swimming.   And remember, these elevated hormone levels will decrease after your first trimester, so don’t write off exercises that may feel too uncomfortable, as they may become easier. 

You may also have pain from your uterine ligaments in your second trimester, but this too will change.  There are several ligaments supporting your growing uterus.  These ligaments stretch as your uterus expands and tighten with sudden movements.  In the nonpregnant woman, the uterus is an almost-solid structure weighing about 70 g (or 1.5 lbs) and with a cavity of 10 mL (or 2 teaspoons) or less. During pregnancy, the uterus is transformed into a relatively thin-walled muscular organ of sufficient capacity to accommodate the fetus, placenta, and amniotic fluid. The total volume of the contents at term averages about five liters but may be twenty liters (about five gallons) or more. By the end of pregnancy, the uterus has achieved a capacity that is 500 to 1000 times greater than in the nonpregnant state.  That equals approximately 1100g (or 2.4 lbs)! (Bloom 2009. 

During your second trimester, you will also experience some muscle soreness from your recent weight gain, change in posture, and new demands on your body.  Should this happen, please let your doctor or midwife know.  It may be a musculo-skeletal issue that can easily be addressed by a physical therapist or other health care provider.  

3. “Don’t let your heart rate get higher than 140 beats per minute when exercising. 

This “rule” was written in 1985, but then amended in 1994 by the American Congress of Obstetricians and Gynecologists.  However, many health care providers and institutions still follow this antiquated guideline.   James F. Clapp III, M.D. has been the world’s foremost researcher in the area of exercise and pregnancy since the early 1980`s.   It was based on his findings that this addendum was added in 1994 eliminating the 140-bpm heart rate rule and guiding women to use the “talk-test” as a way to measure intensity. The “talk-test” is when the expecting mother works out at an intensity where they can speak 3-5 word sentences.  Anything less, they are working out too hard, anything more, they can pick up the pace within their comfort level. (Clapp, JF (2012) Exercising Through Your Pregnancy. Nebraska: Addicus Books.)   Also, note that studies that were first done to determine appropriate heart rates for pregnant females were performed on pregnant female animals.  It was only recently that studies started taking into account pregnant human females.  This may be a good reason why guidelines keep changing. 

So how do you know how hard to work out?  What are the current guidelines?  You need to measure how you feel, not what your heart rate monitor reads.  You should be able to hold a conversation and not feel overheated or out of breath.   If you can’t speak normally while you’re working out, you’re probably pushing yourself too hard. This could lead to vaginal bleeding, uterine contractions or other problems, according to Dr. Roger W. Harms, of the Mayo Clinic.  While there have been no studies looking specifically at the effects of intense training on pregnancy, guidelines set by the federal Department of Health and Human Services say that women can sustain the level of physical activity they engaged in prior to pregnancy.  Make sure to keep your body cool by staying hydrated and wearing loose or moisture-wicking clothing.  

4. “Too much exercise will take nutrients away from your baby.”

Some propose that exercise reduces the rate of oxygen and nutrient delivery to the developing fetus as the body shunts blood away from internal organs to supply the exercising muscles.  This won’t happen.  The normal physiologic adaptation to pregnancy is increased cardiac output and blood volume. This additional blood flow constitutes a significant portion of your pregnancy weight gain.    Additionally, the placenta (the organ that connects the baby to the mom’s blood supply) is designed to ensure constant nutrient delivery during a healthy pregnancy. There is no retrospective evidence to suggest that exercise leads to fetal distress, premature delivery, or low birth weight (Kramer 2002).   

5. “If you never exercised before pregnancy, don’t start now.”

Don’t let this rumour deter you.  The American Congress of Obstetrics and Gynecology (ACOG) encourages pregnant women to be evaluated before starting a new exercise program and participating in low-impact activities.  Stretching, walking, pelvic floor exercises and breathing exercises are also safe.  Besides the psychological health benefits of feeling better, releasing stress, sleeping better, and clearing your head,  women show physical improvements in their cardiovascular endurance, blood pressure levels, body fat index, muscular strength and endurance, and maximum heart rate.  (ACOG 2002)

A supervised and structured exercise regimen provides little if any risk to the mom or baby.  That being said, pregnancy isn’t a time to be ultra-competitive.  It is a time to take care of yourself and the little one in your belly.  

You do, however, have a legitimate excuse to bench yourself from some activities.   Collision sports such as hockey and basketball should be avoided as should sports with a high incidence of falling, such as skiing and horseback riding.  Since a protective cup for your belly hasn’t yet been invented, you need to avoid the risk of trauma to your baby through a direct blow or fall.  Tuck those riding boots and skates away for a few more months.  

If you have abdominal pain while exercising that is lasting longer than a few seconds, you should contact your doctor or midwife immediately. It may be from preterm labor, preeclampsia, placental abruption, or a medical problem unrelated to pregnancy.  

When else should you throw in the towel? The American College of Sports Medicine (ACSM) lists several reasons to discontinue exercise and seek medical advice during pregnancy:

1. Any signs of bloody discharge from the vagina.
2. Any “gush” of fluid from the vagina (premature rupture of membranes).
3. Sudden swelling of the ankles, face, or hands.
4. Persistent, severe headaches and/or visual disturbance; unexplained spell of faintness or dizziness.
5. Swelling, pain, and redness in the calf of one leg (phlebitis).
6. Elevation of pulse rate or blood pressure that persists after exercise.
7. Excessive fatigue, palpitations, chest pain.
8. Persistent contractions (>6 to 8/hour) that may suggest onset of premature labor.
9. Unexplained abdominal pain.
10. Insufficient weight gain (<1.0 kg/month or <2.2 pounds/month) during the last two trimesters.

 

 You should see your doctor or midwife immediately for an evaluation should these symptoms occur.  If you are experiencing back pain, join pain, muscle soreness, or other pregancy-related pain, please come in for an evaluation.  You will feel better as soon as you you lie on my specialized prenatal treatment table! 

 

REFERENCES

American College of Obstetricians and Gynecologists. (2002) Exercise during pregnancy and the postpartum period. American College of Obstetricians and Gynecologists Committee Opinion No. 267. Obstet Gynecol. 99:171–173.

American College of Sports Medicine (2013).  ACSM’s Resource Manual for Guidelines for Exercise Testing and Prescription. New York: Lippincott Williams & Wilkins

Bloom S, Cunningham F, Leveno K, Hauth J, Rouse D, Spong C.  (2009).  Williams Obstetrics. McGraw Hill: New York.

\Evenson KR, Marshal SW, Vladutiu CJ.  Physical activity and injuries during pregnancy. J Phys Act Health. 2010 November; 7(6): 761–769.

Hakakha M, Brown A. (2010). Expecting 411. Boulder: Windsor Peak Press. 

Hegaard HK, Hedegaard M, Damm P, Ottesen B, Petersson K, Henriksen TB. Leisure time physical activity is associated with a reduced risk of preterm delivery. Am. J. Obstet. Gynecol. 2008;198(2):180 e1–180 e5. 

http://my.clevelandclinic.org/healthy_living/pregnancy/hic_correct_posture_and_body_mechanics_during_pregnancy.aspx

Kramer, M.S. (2006) Aerobic exercise for women during pregnancy. Cochrane Database Syst Rev. 2006;(3):CD000180. 

United States Department of Health and Human Services, Healthy People 2010. (2000, Nov). Retrieved from

http://www.healthypeople.gov/2020/default.aspx