Many pregnant women are concerned about the effects of exercising during pregnancy but the good news is that, for the vast majority of women, it is not only safe for the baby but good for you both! Here we discuss how to exercise safely and signs to look out for that suggest you shouldn’t exercise. If you have any concerns, or if you are not used to exercising regularly, you should always talk to your doctor or midwife before starting to exercise.
What are the benefits of exercising during pregnancy?
Women who exercise during pregnancy can expect to experience a number of benefits:
- a reduction in tiredness, varicose veins, ankle swelling and breathlessness
- reduced risk of developing gestational diabetes
- possible reduced labour time
- minimise excessive maternal weight gain
- reduced risk of pre-eclampsia
- reduced rate of pelvic and low back pain
- reduced stress, anxiety and depression.
For the baby, there may be less chance of becoming distressed during delivery (though this has many different causes) and it may help to enhance brain development during infancy.
When shouldn’t women exercise during their pregnancy?
Most pregnant women can exercise safely during pregnancy. However, there are a few conditions where it may be risky for the mother and/or the baby. The list below may be rather long, but the number of pregnancies that are actually affected by one of these conditions is quite low and they don’t always mean that you can’t do any exercise. However, you’ll need specialist advice about what is or isn’t safe for you to do.
If you have been diagnosed with something on the list below, or have any concerns about pregnancy-related symptoms, then it is always best to speak to your doctor or midwife before starting to exercise.
- Maternal conditions
- significant heart or lung disease
- poorly controlled; high blood pressure, type 1 diabetes, epilepsy or hypethyroidism
- pre-eclampsia/pregnancy induced high blood pressure
- •very low iron levels (haemoglobin level less than 10)
- being very overweight or underweight (bmi >40 or <12)
- being very sedentary prior to pregnancy
- smoking over 20 cigarettes a day
- severe back, pelvic or other joint pains
- Risk of premature labour / bleeding
- incompetent cervix (if you’ve had a history of recurrent late miscarriages then this can be the cause and you should talk to your doctor about whether you can keep exercising)
- multiple gestation (twins or more)
- persistent bleeding in the second or third trimester
- placenta praevia after 26 weeks (where the placenta is low-lying and covers the exit from the womb)
- premature labour during current or previous pregnancy
- if your waters have broken
- Foetal conditions - restricted growth of the baby during current pregnancy
Are the any risks to exercising during pregnancy for otherwise healthy women?
Beyond the conditions listed above, then there is no evidence that there is an increased risk of complications for the mother or the baby if the woman exercises during her pregnancy. Babies of mothers who exercise regularly throughout their pregnancy or have strenuous physical jobs may be born slightly smaller (but still of a healthy weight). However the evidence is mixed on this point.
One concern that is often raised is about the risk to the baby if a pregnant woman overheats (hyperthermia); for example, if they have a high fever during an illness. During the first trimester in particular, this can increase the risk of developmental problems in the baby. There is no evidence that becoming slightly warm during exercise can cause this – however the advice is always to make sure you don’t become uncomfortably warm during exercise. If you find yourself feeling a bit hot, stop and rest until your body temperature feels normal again. Drinking plenty of fluids during exercise will also help. Pregnant women shouldn’t exercise outside if it is a hot day and should avoid Bikram yoga, which is practised in a hot room.
Are there any signs I should look out for that mean I should stop exercising?
There are a few signs that mean you should stop exercising. If you experience any of these symptoms while you are exercising, then you should speak to your midwife or doctor straight away.
- Maternal symptoms
- feeling excessive breathless during exercise or feeling breathless before starting to exercise
- chest pain or palpitations
- fainting or dizziness
- being very tired
- headache
- calf pain or swelling
- Signs of premature labour / bleeding
- painful uterine contractions
- abdominal pain especially with back and/or pelvic pain
- amniotic fluid leakage (‘waters broken’)
- vaginal bleeding
- Foetal compromise
What sort of exercise should I do and how much?
The recommendation from the Royal College of Obstetricians and Gynaecologists is that pregnant women should do 30 minutes of moderate-intensity exercise on most days of the week. ‘Moderate intensity’ exercise means that you can still talk and hold a conversation but that your sentences will be shorter. If you are used to monitoring your heart rate during exercise, then this equates to a maximum of 50 to 70 per cent of your heart rate. But unless you are used to training in this way, there is no need to start monitoring your heart rate just because you are pregnant.
It’s good to do a variety of exercise that will include activities to raise your heart rate, improve your strength and work on your core muscles. For example:
- swimming/aqua aerobics (the water temperature should not be above 32° C)
- walking
- jogging/running
- yoga/pilates
- gym and gym classes
- dancing
- pelvic floor exercises
In general, if you are used to exercising, then you can continue what you usually do, provided you feel well enough (with a few exceptions, see below). As you progress into your second and third trimester then you’ll naturally need to reduce the intensity and impact of the exercise and some exercises may become more difficult to do. If you are exercising with a trainer or in a class you should always tell the instructor that you are pregnant so they can show you any modifications to exercises that you might need.
Are there any sports I shouldn’t do if I’m pregnant?
Most of the activities that aren’t suitable during pregnancy relate to the risk of trauma to the abdomen, for example:
- contact sports such as rugby or martial arts (unless practiced alone)
- sports where there is a risk of falling such as riding or skiing
- sports where there is a risk of being hit in the abdomen by equipment such as tennis or squash
- scuba diving
- exercising at high altitude (above 6,000 feet)
What if I haven’t been exercising regularly before I became pregnant?
If you aren’t used to doing much regular exercise before you became pregnant, then it is still a good idea for you to become more active. If you are very unfit you should talk to your doctor first, but otherwise going for walks is a good way to start.
Begin with fifteen-minute walks three times a week and then build up to 30 minutes on most days. You should aim to be walking at a ‘moderate intensity’ which means you should feel slightly sweaty and breathless, but you are still able to talk. Once you are used to doing some walking on a regular basis you can start to do other types of exercise (see above).
How might my exercise need to be different now I’m pregnant?
There are some specific things you need to be aware of during pregnancy. Due to hormonal changes during pregnancy, a women’s flexibility can increase. Therefore stretching exercises should be used to maintain or restore rather than increase your usual flexibility. This increased flexibility, coupled with your expanding bump and weight gain, mean that there can be more pressure through your joints. To minimise your chance of injury or pain, include some core stability and strength type exercises. A pilates class run by an instructor who is trained in advising pregnant women is a good place to start.
As your bump starts to expand (as you progress through your second trimester) then it is not advisable to lie flat on your back. This is because the weight of the baby presses down on the big vein in your abdomen so it may restrict blood flow to your baby and you (causing you to feel light headed). If you are used to doing exercises such as pilates, yoga and some free weights exercises which include lying on your back, then you will need to modify these. Your instructor or trainer should be able to give you suitable adaptations (for example, doing the exercise in a more upright position) or give you an alternative exercise to work the same muscles. If you’re lifting weights as part of your exercise routine you’ll need to reduce the amount you lift as your pregnancy progresses.
The most important thing is to listen to your body. If it feels uncomfortable or painful it’s not the right exercise for your stage of pregnancy. For further advice talk to your trainer or class instructor, if you have one; or ask your midwife, physiotherapist or specialist.
What about exercising after the baby arrives?
Your hormone levels remain high for at least four to six weeks after delivery, meaning that your ligaments will still be soft and your risk of injury is still slightly higher than usual. These effects will last longer if you are breast-feeding. In addition you have the small matter of the birth itself to recover from, along with the joys and challenges of caring for your newborn! For all these reasons there is no need immediately rush back into exercising after you’ve given birth. Pelvic floor exercises are good to start as soon as possible (or restart, as hopefully you’ve been practising them during your pregnancy as well). After that, walking is the best first step; take your baby out in their pram and you can both escape the house! Often this can help to combat any ‘baby blues’ and also help your baby to sleep.
After an uncomplicated vaginal delivery (no forceps or suction, and no tearing) you can begin walking, pelvic floor and stretching exercises as soon as you feel able to. Increase the amount of walking gradually, e.g. ten to 30 minutes a day, at low to moderate intensity. After your six-week check you can start doing other activities, when you feel ready to.
After a complicated vaginal delivery or Caesarean section, you should wait for six weeks and until you’ve had your check with your GP before starting to build up your physical activity. Start with walking and continuing your pelvic floor exercises.
This article is based on a presentation given by ISEH consultant Eleanor Tillett at the Sports Injuries and Sports Orthopaedics Conference in January 2015.