Considerations for Exercise in Pregnancy: An overview of safe and beneficial pre-natal training.
Updated: Jun 16, 2021
GUIDELINES
'Women with uncomplicated pregnancies should be encouraged to engage in aerobic and strength and conditioning exercises before, during, and after pregnancy.
The 2018 update to the U.S. Department of Health and Human Services Physical Activity Guidelines for Americans reinforces prior recommendations of at least 150 minutes of moderate intensity aerobic activity per week during pregnancy and the postpartum period.' (American College of Obstetricians and Gynaecologists, 2020)
'The guidelines advise that women who habitually engaged in vigorous-intensity aerobic activity or who were physically active before pregnancy can continue these activities during pregnancy and the postpartum period. Pregnant women who were sedentary before pregnancy should follow a more gradual progression of exercise.' (ACOG, 2020)
'Pregnant women should incorporate a variety of aerobic and resistance training activities to achieve greater benefits. The findings of the systematic reviews also demonstrated that combining aerobic exercise and resistance training during pregnancy was more effective at improving health outcomes than interventions focused on aerobic exercise alone.'
(Canadian Guidelines, 2019)
BENEFITS OF EXERCISE
Higher incidence of vaginal delivery.
Lower incidence of:
Excessive gestational weight gain
Gestational diabetes mellitus
Gestational hypertensive disorders
Preterm birth Cesarean birth
Lower birth weight
(ACOG, 2020)
'According to the subgroup analysis, a higher rate of normal delivery and lower rate of cesarean delivery were observed in the intervention group when exercise was performed during the second and third trimesters.' (Poyatos-León, 2015)
'Dose–response relationship between increasing intensities of physical activity and decreasing odds of pre-eclampsia, gestational diabetes, gestational hypertension, and a reduction in depressive symptoms and circulating maternal blood glucose.' (Canadian Guidelines, 2020)
Our meta‐analysis supports the hypothesis that physical exercise during pregnancy increases the likelihood of normal delivery, probably due to an improvement in maternal cardiovascular function and/or a limited pregnancy weight gain. The improvement in aerobic condition during pregnancy may play a role in allowing women to maintain more effectively the effort required during childbirth, particularly during the second stage of delivery, and principally during pushing efforts.' (Poyatos-León, 2015)
RISK OF COMPLICATION
'Concerns that regular physical activity during pregnancy may cause miscarriage, poor fetal growth, musculoskeletal injury, or premature delivery have not been substantiated for women with uncomplicated pregnancies' (ACOG, 2020)
'Physical activity is not associated with miscarriage, stillbirth, neonatal death, preterm birth, preterm/prelabour rupture of membranes, neonatal hypoglycaemia, low birth weight, birth defects, induction of labour or birth complications.' (Canadian Guidelines, 2019)
'Although exposure to heat from sources such as hot tubs, saunas, or fever has been associated with an increased risk of neural tube defects, exercise would not be expected to increase core body temperature into the range of concern.' (ACOG, 2020)
Examples of exercises that have been extensively studied in pregnancy and found to be safe and beneficial:
Aerobic exercises
Resistance exercises (e.g. using weights & bands)
Walking
Dancing
Stretching exercises
Stationary cycling
Water aerobics
REASONS TO STOP ACTIVITY And consult a healthcare provider:
Persistent excessive shortness of breath that does not resolve on rest.
Severe chest pain.
Regular and painful uterine contractions.
Vaginal bleeding.
Persistent loss of fluid from the vagina indicating rupture of the membranes.
Persistent dizziness or faintness that does not resolve on rest.
(Canadian Guidelines, 2019)
TRAINING SAFELY
Safety precautions for prenatal physical activity:
Avoid physical activity in excessive heat, especially with high humidity.
Avoid activities which involve physical contact or danger of falling.
Avoid scuba diving.
Lowlander women (ie, living below 2500 m) should avoid physical activity at high altitude (>2500 m).
Those considering athletic competition or exercising significantly above the recommended guidelines should seek supervision from an obstetric care provider. Maintain adequate nutrition and hydration—drink water before, during and after physical activity.
Know the reasons to stop physical activity and consult a qualified healthcare provider immediately if they occur.
(Canadian Guidelines, 2019)
PRACTICAL APPLICATIONS
'High-impact activities with increased risk of blunt trauma should be avoided, and it also is important that the pregnant athlete avoid overheating when performing their sport or participating in intense training.' (ACOG, 2020)
What's the risk? What's the benefit? Which exercises have low risk and high benefit?
No evidence of higher risk of complication or miscarriage from any specific movement, however some movements may lend themselves to higher likelihood of falls, equipment malfunction or human movement error.
Centre of gravity may change as pregnancy progresses and anatomy changes so exercise modification may be warranted. E.g.
Standing -> seated overhead work.
Flat shoes to squat in rather than raised heels.
Less/ no lying exercises that may be difficult to get up from. Low quality evidence suggests avoiding long periods in a supine position. (Canadian Guidelines, 2020)
Bent over row with a bar could be swapped for cambered bar or DB single arm row with support.
Exercising in a prone position seems unlikely to be worth pursuing as pregnancy progresses. E.g. floor push ups, lying row variations, supermans.
Exercises with impact and risk of fall seem unlikely to be worth doing at this time. I.e. box jumps, burpees, skipping, high step ups.
Dynamic movements with changes in direction or unstable single leg movements (without support) seem unlikely to offer any unique benefit at this time.
Olympic lifting seems unwise beyond the first trimester, even in athletic populations, due to bar contact.
No contact sports, kickboxing, horse riding, downhill skiing, ice hockey, or gymnastics for obvious reasons.
Non-stationary cycling is not recommended due to risk of fall from environmental changes such as traffic or road surfaces. Jogging seems dependent on the above and exercise history. Brisk walking, stationary cycling, swimming and water aerobics are deemed as safe, low impact, cardiovascular options.
Very high intensity exercise is unlikely to provide additional benefits for those not currently accustomed to it. Use of RPE can be used to gauge intensity of work.
Due to pressure on the bladder as pregnancy progresses some movements that may cause a leak of urine may benefit from a reduction in load or a modification.
VALSALVA MANOUEVER
Definition: a forced expiration against a closed glottis. This can occur when a person strains while having a bowel movement or lifting a heavy weight when holding their breath.
'[Resistance training] was not considered a safe activity in early guidelines... because of potential injury and possible fetal heart decelerations resulting from Valsalva manoeuvres. Consequently, there is sparse literature on this topic. Athletes who wish to continue strenuous activity during pregnancy should have an understanding of the risks, obtain approval from their HCPs, and to consider decreasing resistance load compared with pre-pregnant conditions.' (ACOG, 2020)
'Women who experience light-headedness with excessive Valsalva manoeuvre (straining while holding one’s breath) when exercising should avoid the breath-hold.' (Canadian Guidelines, 2020)
DIASTASIS RECTI
Definition: separation of rectus abdominis muscles away from the midline, sometimes seen during or following pregnancy.
'Continuing aerobic exercise such as walking is associated with decreased odds of developing diastasis recti. While there has been less research on resistance exercises as compared with aerobic exercises in pregnancy, available evidence regarding resistance exercise in pregnancy has not identified adverse impacts on the mother, the fetus or the neonate.' (Canadian Guidelines, 2019)
'Abdominal strengthening exercises, including abdominal crunch exercises and the drawing-in exercise have been shown to decrease the incidence of diastasis recti abdominus and decrease the inter-rectus distance in women who gave birth vaginally or by cesarean birth.' (ACOG, 2020)
ONLINE COACHING
If you've become pregnant or are looking to become pregnant and would like to engage in an active, healthy pregnancy, online coaching can help you.
Work with a certified personal trainer to:
Achieve the benefits of exercise in pregnancy and reduce risks associated with being sedentary
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Post references
Birsner, M. and Gyamfi-Bannerman, C., 2020. Physical Activity And Exercise During Pregnancy And The Postpartum Period. [online] Acog.org.
Mottola, M. and Davenport, M., et al. 2018. 2019 Canadian guideline for physical activity throughout pregnancy. British Journal of Sports Medicine, 52(21), pp.1339-1346.
Poyatos-León, R. and García-Hermoso, A., 2015. Effects of exercise during pregnancy on mode of delivery: a metaanalysis. Acta Obstetricia et Gynecologica Scandinavica, 94(10), pp.1039-1047.
