Exercise should form a major part of a healthy pregnancy. Certain modifications should however be made to ensure safety and effectiveness.
Numerous changes in the body occur during pregnancy, with implications from each affecting and determining exercise requirements and safety.
- Change: Increased body weight.
Implication: Changes in centre of gravity. Difficulties in changes directions rapidly.
- Change: Increased ligament laxity.
Implication: Caused by increases in levels of hormone ‘relaxin’. Increased risk of falls and injury.
- Change: Increased resting heart rate.
Implication: Less exercise required to reach a high heart rate.
- Change: Decreased blood pressure.
Implication: Should avoid rapid changes in posture, never stop exercising suddenly and avoid supine (lying on back) exercise.
- Change: Increased blood volume, haemoglobin levels and VO2 max.
Implication: Occurs due to an increased requirement to deliver oxygen to the foetus and muscles. Must reduce intensity and duration of exercise to ensure adequate blood supply.
- Change: Weakening of pelvic floor muscles.
Implication: Exercise putting excessive pressure on the pelvic floor should be avoided, especially high impact exercise. Exercises to strengthen the pelvic floor should be undertaken.
- Change: Lower back pain.
Implication: Caused by a shift of the centre of gravity forwards and upwards. To compensate, the shoulders are slumped and the back is arched. Strengthening of postural muscles to avoid the negative changes is required.
Exercise during pregnancy has the tendency to affect the following factors:
- Onset of labour: Continued exercise during pregnancy does not cause the premature onset of labour. Exercisers deliver at term more than non-exercisers.
- Course of labour: 50% less medical intervention in exercisers. More spontaneous deliveries in exercisers. Decreased length of labour for exercisers.
- Foetal growth: No adverse effects.
- Foetal stress/distress: No increases.
- Maternal wellbeing: Exercise causes reduced weight gain, and a maintenance (or increase) of fitness.
- Breast feeding: No adverse effects.
There are several situations to avoid during exercise when pregnant:
- Exercise where balance is a safety factor
- Supine exercise (on back)
- Jarring and ballistic exercise
- Excessive fatigue
- Sudden changes in direction and posture
There are five major contraindications to exercise in pregnancy:
- Foetal disease
- Myocardial disease
- Heart failure
- Recent embolism
- Infectious disease
Exercise is an important part of a healthy pregnancy. With proper programming and responsible prescription, this will lead to increased health and wellbeing for both the mother and infant.