This piece was written by one of our contributors; medical student – Mary Moore.
In the past, pregnant women were considered vulnerable and were often advised to reduce their level of physical activity. In many cases, this belief can still exist in society today. However, it is recommended that pregnant and postpartum women engage in 150 minutes of moderate intensity physical activity per week and muscle strengthening activities twice per week (1)
Despite this advice, physical activity participation is often lower in pregnant women than in the general population – it is estimated that only 3-15% of pregnant women are meeting the guidelines compared with 24-26% of non-pregnant women (2). This suggests that women who were active before becoming pregnant are falling out of the habit.
Exercising while pregnant is usually regarded as safe and is recommended by the Chief Medical Officer (CMO) in the UK and by health organisations around the world. Unless otherwise advised by your physician with medical evidence to back their decision, exercising while pregnant provides many benefits for both mother and baby.
Benefits of exercise during pregnancy
There are many benefits to exercising while pregnant which can include:
- Reduced likelihood of gestational diabetes (pregnancy-related diabetes)
- Decreased risk of pre-eclampsia (a condition that causes high-blood pressure during pregnancy and labour)
- Reduced lower back pain, easier labour and delivery
- Reduced risk of perinatal depression and poor body image
#1: Reduced likelihood of gestational diabetes
Gestational diabetes is the most common medical issue associated with childbirth, affecting up to 10% of pregnancies (3). If gestational diabetes develops, both mother and child are at increased risk of developing obesity and even diabetes (3). Women who are physically active/exercise before and/or during pregnancy have been shown to have decreased risk of developing gestational diabetes by 59% during pregnancy (4,5). Exercise also prevents excess weight gain in pregnancy and is associated with reduced risk of large-for–gestational age newborns, a common concern with gestational diabetes (6, 7).
#2: Decreased risk of pre-eclampsia
Pre-eclampsia is a condition that occurs during pregnancy that includes high blood pressure, proteinuria (protein in the urine), and oedema (swelling) in the mother, and can occur in up to 8 in 100 pregnancies. Physical activity and exercise is known to be helpful in treating high blood pressure. Women who engaged in regular physical activity during pregnancy displayed a reduction in the risk of pre-eclampsia and high blood pressure during pregnancy by as much as 24% (8).
#3: Reduced low back Pain, labour and delivery
Almost 80% of women report experiencing low back pain while pregnant. Research shows that regular exercise can prevent or counteract lower back stress and prevent low back pain (9). Also regular exercise has been shown to be beneficial with several aspects of labour – Women who participated in an exercise program throughout their pregnancy were less likely to need a Caesarean section or operative-assisted vaginal delivery (10). Exercise is also associated with reduced risk of premature labour and duration of labour (11, 12).
#4: Reduction in perinatal depression and poor body image
Evidence shows that exercise throughout pregnancy (1 – 4 times per week) is associated with lower rates of depression, which is a common concern in pregnant women (14, 15, 16, 17). Also, researchers have found that women who exercised during pregnancy felt better about their body image compared with non-exercisers (18, 19).
In addition to these outcomes, pregnant women may continue to experience the same benefits as the adult population, including improved sleep and mood.
When is it not safe to exercise?
Your doctor may advise against exercise in some circumstances, such as if you are classed as a high-risk pregnancy. Familiarity with absolute (do not exercise) and relative (talk with a medical professional before exercising) contraindications to exercise is important for both the physician and patient (20, 21, 22).
Absolute contraindications refer to conditions where moderate-to-vigorous intensity physical activity (MVPA) is not recommended as the risks outweigh the potential benefits and could result in adverse effects for the mother and/or foetus, however, activities of daily living may continue (light housework, going to work, ambulating).
These conditions include:
- Severe respiratory diseases (e.g. chronic obstructive pulmonary disease, restrictive lung disease, cystic fibrosis, etc.)
- Severe acquired or congenital heart disease with exercise intolerance
- Uncontrolled or severe arrhythmia
- Placental abruption
- Vasa previa
- Uncontrolled type 1 diabetes
- Intrauterine growth restriction (IUGR)
- Active preterm labour (i.e. regular and painful uterine contractions before 37 weeks of pregnancy)
- Severe pre-eclampsia
- Cervical insufficiency
Relative contraindications refer to conditions where activity should be approached with caution and discussion with a healthcare professional is advised. The advantages and disadvantages of low-to-moderate intensity physical activity should be considered and may potentially proceed subject to modifications, supervision and with continuous monitoring (decreasing intensity of exercise, frequent rest periods during exercise, monitoring heart rate, working with a qualified healthcare and exercise professional) (20, 21, 22).
These conditions include:
- Mild respiratory disorders
- Mild congenital or acquired heart disease
- Well-controlled type 1 diabetes
- Mild pre-eclampsia
- Preterm premature rupture of membranes (PPROMs)
- Placenta previa after 28 weeks
- Untreated thyroid disease
- Symptomatic, severe eating disorders
- Multiple nutrient deficiencies and/or chronic undernutrition
- Moderate-heavy smoking (>20 cigarettes per day) in the presence
- of comorbidities
Exercise Guidelines During Pregnancy
Not active? Start gradually
If you have an uncomplicated pregnancy* and you’re new to activity, starting gradually building up your activity levels. Moderate activity is an activity that makes you breathe faster whilst still being able to hold a conversation.
Already active? Keep going
If you have an uncomplicated pregnancy* and you’re already active, it is safe to continue with physical activities throughout pregnancy. Pregnant women who are already active should be encouraged to adapt, not stop, their physical activity. Some activities may feel different due to the physiological changes associated with being pregnant and may require adaptation as pregnancy progresses. For example, contact sports can be replaced with non-contact sports or a suitable alternative activity. Strength exercises performed whilst lying flat on the back can be adapted to side or sitting exercises. Adaptations should also be considered for any physical work-related tasks.
Generally, if it feels pleasant keep going, if it is uncomfortable stop and seek advice.
Break up sitting time
Avoid prolonged periods of sitting and to break up sedentary time with at least light physical activity. This reflects the guidelines for the adult population which indicate we should move more, and sit less.
Typically, an uncomplicated pregnancy refers to one where a woman does not experience any symptoms or conditions that are caused or aggravated by their pregnancy. This means that most pregnant women can participate in physical activity throughout pregnancy except for those who experience certain contraindications (more below)
Exercises to avoid
There are also a number of types of exercise that should not be completed during pregnancy, including:
- Supine (lying face up) position after first trimester (However, pregnancy specific yoga or pilates classes should not include these exercises and can be encouraged)
- Exercise with a high risk of contact, falling, or abdominal trauma (e.g. horse riding or skiing)
- Exercise at altitudes greater than 6000 feet (due to concerns that the fetus may not receive enough oxygen)
- Activities completed in high temperatures (due to overheating).
- Scuba diving (due to possibility of decompression sickness and gas embolism)
Stop exercise immediately if you experience any) (23, 24, 25, 26):
- Vaginal bleeding
- Abdominal pain
- Regular or painful contractions
- Dizziness or faintness that does not resolve with rest
- Calf pain or swelling
- Shortness of breath before exertion or persistent SOB that does not resolve with rest
- Chest pain
- muscle weakness affecting balance
- severe pelvic girdle pain that does not improve within a week or two, or interferes with day to day living.
A Note on High-intensity Exercise During Pregnancy
It is becoming increasingly more common for pregnant women to be taking part in high intensity sports and strenuous exercise throughout pregnancy. While there are limited studies that have examined the safety of high-intensity exercise on the developing baby, the results seem reassuring (27, 28, 29, 30). High intensity exercise has been associated with decreased risk of preterm birth with increased frequency of first trimester vigorous recreational physical activity. Great care should be taken to avoid prolonged bouts of highly vigorous activity as this is associated with a reduction in blood flow to the foetus and reduction in foetal heart rate, which can resolve soon after exercise is stopped (27, 28, 29, 30). Short bouts of high intensity work followed by adequate rest are necessary.
The national guidance for being active during pregnancy is underpinned by three key safety messages
- No evidence of harm: Pregnant women may be concerned that physical activity is not safe. However, there is no evidence suggesting adverse outcomes to mum or baby for healthy women resulting from moderate intensity physical activity.
- Don’t bump the bump: Certain activities may represent an increased risk of injury through physical contact. Therefore, avoid contact sports and activities where there is a high risk of falls/trauma.
- Listen to your body and adapt : Some activities may feel different due to physiological changes and may require adaptation as pregnancy progresses. A general rule is if it feels pleasant keep going, if it is uncomfortable stop and seek advice.
- See figure 1 for a detailed overview of the various types of physical activity to engage in during pregnancy.
Useful Resources for mums-to-be (and professionals)
Figure 1. UK National Guidelines for Physical Activity During Pregnancy (31) (https://c530d8c7-bdad-4776-b32f-0ab61851288f.filesusr.com/ugd/2eb4ca_25c747c05f6644bcbbcaa02a0f3849e9.pdf)
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(2) Liu, J., Laditka, J. N., Mayer‐Davis, E. J., & Pate, R. R. (2008). Does physical activity during pregnancy reduce the risk of gestational diabetes among previously inactive women?. Birth, 35(3), 188-195.
(3) de Barros, M. C., Lopes, M. A., Francisco, R. P., Sapienza, A. D., & Zugaib, M. (2010). Resistance exercise and glycemic control in women with gestational diabetes mellitus. American journal of obstetrics and gynecology, 203(6), 556-e1.
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(31) UK National Guidelines for Physical Activity During Pregnancy (https://c530d8c7-bdad-4776-b32f-0ab61851288f.filesusr.com/ugd/2eb4ca_25c747c05f6644bcbbcaa02a0f3849e9.pdf)