Although exercise in pregnancy should be done under medical guidance, assuming there are no medical risks and no sudden increase in exercise levels, there are numerous benefits including a reduction in fatigue, constipation, varicose veins, and swollen feet and ankles. Those who exercise are also less likely to experience stress, anxiety and depression, and will experience better sleep patterns.
Research has also shown that there may be a protective effect on coronary heart disease, osteoporosis and hypertension.
Conversely, being sedentary during pregnancy can result in reduced cardiovascular and muscular fitness, excessive weight gain, and increased risks of gestational diabetes mellitus, pre-eclampsia, and varicose veins.
Research also suggests that the foetuses of exercising women may tolerate labour better than those of non-exercising women and that foetal stress during labour is less in women who continue to exercise at 50% of the levels they were before pregnancy, than it is in those who had exercised before and discontinued within the first three months of the pregnancy.
Precautions to take:
Both exercise and pregnancy raise the metabolic rate, so it is important to keep body temperature from rising excessively (hyperthermia), for example by exercising with few or loose clothes, in a cool environment or with the use of a fan. Pregnant women do, however, perspire more readily which helps with temperature control but plenty of water should be drunk to remain hydrated.
Pregnant women are more likely to become hypoglycaemic (low blood sugar), so adequate calories should be eaten before and after exercise.
Avoid exercising supine (lying on your back) after the 16th-20th weeks. The pressure of the baby can compress the vena cava and reduce blood flow in the mother, resulting in feeling faint, associated with lower maternal cardiac output in this position and symptomatic hypotension.