Gone are the days when pregnant women were advised to put their feet up and take things easy. A gentle stroll was once considered their physical limit and experts recommended they cover no more than a mile a day. But over the past 15 years the medical profession has been rethinking that advice.
The recently revised guidelines of the American College of Obstetricians and Gynaecologists (Acog), which are also advocated by UK experts, now recommend that pregnant women with no medical complications should do a minimum of 30 minutes of moderate activity most days.
Exercise was once thought capable of damaging a foetus by starving it of blood and oxygen, but studies have proven this is not the case. A pregnant woman's heart pumps far more blood than normal, so the foetus is not deprived when she works out. In fact, babies born to women who exercise tend to be less fat, more responsive and more alert.
Studies have also shown that active pregnant women typically report fewer backaches and less sickness, swelling and shortness of breath - and often have an easier labour. "Exercise gives them a more positive approach overall," says Professor Raul Artal, chair of the department of obstetrics and gynaecology at St Louis University Medical Centre and an adviser to Acog.
Certain precautions do need to be applied, however. According to Acog, jerky, bouncy or high-impact movements, such as aerobics or running, should be limited during later stages of pregnancy, while activities that take place in low- or high-oxygen environments, like skiing or scuba diving, should be avoided altogether. Since the body produces extra heat during pregnancy, there is also a danger of overheating when working out. Acog recommends wearing light clothing, drinking plenty of fluids to avoid dehydration and resisting the temptation to use Jacuzzis and steam rooms. Although using light hand weights is deemed fine throughout pregnancy, Artal advises against pushing heavy weights that may compromise blood flow to the womb.
Back pain is a common complaint during pregnancy, with at least 50% of women claiming to suffer. Specific antenatal yoga and Pilates classes or swimming can relieve it. Trying yoga for the first time, though, might not be a good idea. Artal says a woman's body secretes raised levels of relaxin, a hormone that makes muscles more supple and joints more pliable, especially during the final trimester. Women who do find that their joints become notably more mobile should avoid weight-bearing activities and anything requiring extreme suppleness as they are more at risk of injury.
If you can rise above the fatigue, morning sickness and back pain to keep up with your exercise regime during pregnancy, there is one more advantage ahead: gym workouts could seem a breeze after you've given birth. "Childbirth influences a woman's perception of pain," says Dr Richard Godfrey, an exercise physiology researcher at Brunel University. "Pain is a complex mixture of sensory, physical and psychological messages. It is thought that labour can reset the natural pain threshold so that a woman is able to cope with greater levels of discomfort when she resumes exercising. In short, nothing she does will seem as uncomfortable again."
