Chapter 11 - Exercise during Pregnancy
Many pregnant women are concerned about the effects of exercising during pregnancy, but there is now clear evidence that moderate physical activity is not only safe, but also beneficial for both mother and baby. 1,2,3 The recommendation from the Royal College of Obstetrics and Gynaecology (RCOG) and Department of Health 1, 3 is that pregnant women should do 30 minutes of moderate intensity exercise most days of the week.
Benefits of Exercise During Pregnancy 1-4
- reduction in hypertensive disorders
- improved cardiorespiratory fitness
- lower gestational weight gain
- reduction in risk of developing gestational diabetes
Further low – moderate quality evidence exists for in the woman…5, 6
- tiredness, varicose veins, ankle swelling and breathlessness
- rate of pelvic and low back pain
- labour time
- stress, anxiety and depression
For the baby…
- potentially reduced chance of foetal distress during delivery
- may help to enhance brain development during infancy
Pre Exercise Evaluation
Box 1: Cautions and Contraindications to exercise
- Incompetent cervix
- Persistent bleeding in the 2nd or 3rd trimester bleeding
- Placenta praevia after 26 weeks
- Premature labour during current or previous pregnancies
- Ruptured membranes
- Pre-eclampsia/pregnancy induced high blood pressure
- Multiple gestation at risk of premature labour
- Restricted growth of the baby during current pregnancy
- Significant heart or lung disease, poorly controlled hypertension
- Haemoglobin <10
- Poorly controlled Type 1 diabetes, epilepsy or hyperthyroidism
- BMI >40 or <12
- Severe back, pelvic or other joint pains
There are very few absolute contraindications to exercise during pregnancy and these are mostly related to the pregnancy itself e.g. risk of premature labour or presence of pre-eclampsia. However, there are a number of medical conditions where women need to be cautious and specialist input may be required 1 (box 1). In addition, any woman undertaking exercise for the first time should be screened in the usual way to consider any risk factors from their general health. See Contraindications.7
Outside the conditions listed, 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; however, there are a few types of exercise that should be avoided (box 2).
The 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.8
Hyperthermia (>39.2°C): During the first trimester in particular, hyperthermia can increase the risk of developmental problems (e.g. spina bifida). There is no evidence that becoming slightly warm during exercise can cause this, however, the woman should be advised to not become uncomfortably hot. Keeping hydrated will help.
When to stop exercising:
Box 2: Type of Exercise to Avoid
- Scuba diving
- Exercising at high altitude (>6000 feet)
- Exercising in hot temperatures (including Bikram yoga)
After first trimester:
- Contact sports e.g. rugby, martial arts (unless practiced alone)
- Sports where there is a risk of falling e.g. riding, skiing
- Sports where there is a risk of being hit in the abdomen by equipment e.g. tennis, squash
Advise to stop exercising if there is:
- Chest pain, palpitations, presyncope or dizziness, excessive breathlessness
- Painful uterine contractions / preterm labour, abdominal pain especially accompanied with back and/or pubic pain
- Amnioticfluid leakage, PV bleeding
- Reduced foetal movement
- Pelvic pain
- Calf pain or swelling
- Excessive fatigue
- Muscle weakness
‘F.I.T.T.’ For Pregnancy
As with any exercise advice, consider the woman’s exercise history and preferences. If they are used to exercising, then they can probably just adapt what they are already doing. During the first trimester morning sickness and fatigue may limit exercise ability but otherwise women can do most of what they have done previously. In later trimesters they may need more modifications, but most women will naturally reduce the intensity and impact of the exercise as it becomes more challenging.
FREQUENCY – most days of the week
INTENSITY – moderate; an easy way of monitoring the intensity is telling the woman that they should still be able to talk but their sentences will be shorter. Those women who are training more seriously may be used to monitoring their heart rate in which case they should be advised to work at 50% - 70% of their heart rate max. However there is no indication for someone to start monitoring their heart rate just because they are pregnant.
TIME – 30-60 minutes
TYPE – mixture of cardio, strength and stability, for example;
- Swimming / aqua aerobics (water temp not >32deg)
- Jogging / running
- Yoga / Pilates / pelvic floor exercises
- Gym (inform the instructor)
- Dancing etc
Advice for those not used to exercising regularly prior to becoming pregnant; walking is a good way to start. Begin with 10 minute walks every other day and then build up to 30 minutes on most days at a moderate intensity. Once they are used to doing some walking on a regular basis they can add in other types of exercise.
Modifications and Considerations
Due to the production of relaxin, ligaments around the spine, hips and pelvis will soften in preparation for delivery so reducing their stability and potential increasing the risk of injury. Stability exercises (e.g. Pilates – as long as it is modified for pregnancy by an experienced instructor) will help to counter this. Also, this softening will effectively increase a woman’s flexibility so to protect their joints they should not stretch beyond their normal range.
Avoid exercising lying supine or standing still for long periods after 16/40 weeks due to venous compression and pooling.8
The combination of increasing lumbar lordosis and weight puts more strain on the joints, especially in the back and pelvis. In addition as the pregnancy progresses, stress incontinence will become more likely (prevalence 32-64%9). Stability and pelvic floor exercises will help to protect against this; back and pelvic pain is not an inevitability during pregnancy (prevalence 45%10). As the woman progresses through the second and third trimesters they should reduce the amount of any weights they are lifting.
Post Partum Exercise Advice
Hormone levels remain high for at least 4 to 6 weeks after delivery meaning ligaments will still be relatively soft, increasing the risk of injury. These effects will last longer if the woman is breast feeding. Coupled with recovery from the birth and fatigue from caring for a new born, regular training should not be restarted for 6 weeks after delivery (longer if there were complications) (see box 3). Pelvic floor exercises should be restarted as soon as possible and when feeling ready the woman can start going for short walks (before 6 weeks if they want to).
Box 3: Restarting exercise post partum
Uncomplicated vaginal delivery (i.e. no forceps/suction, no tearing)
- Pelvic floor exercises and walking as soon as feels ready
- Increase walking gradually, e.g. 10-30 minutes a day, low to moderate intensity
- Add in other exercise when feels ready and after 6 week check
Complicated vaginal delivery / caesarean section
- Pelvic floor exercises as soon as feels ready
- After 6 week check and when feels ready, gradually build up activity levels, starting with walking
Download the Royal College of Obstetricians & Gynaecologist Guidelines for patients here
Take home message: Exercise is an important part of any treatment plan for a patient who is pregnant. It can improve their health and reduce the risk of gestational diabetes.
Consider: Advising on point of referral the importance of this lifestyle approach for their own well-being.
Benefits for GPs and teams: Reduced appointments and visits.
Use the CMO infographic to help explain to pregnant women the benefits of activity.