Exercise during pregnancy

During an uncomplicated pregnancy exercise is actively recommended for a host of associated maternal and foetal benefits. (1, 2) Sadly, a recent study (that surveyed over 1000 subjects’ physical activity during pregnancy) showed the majority of women did not reach the recommended activity levels (3).

Many pregnant women said they felt anxious about exercise and were unsure of safe levels and modifications to their normal routine. In addition to this, feelings of nausea, fatigue, discomfort during exercise or simply being too busy, are described as limiting factors (4). As exercise professionals, in conjunction with other health care providers, we have an important role in educating and encouraging exercise during pregnancy.

What are the physiological changes during pregnancy? One of the biggest and most rapid changes is a huge increase in cardiac output. Blood volume increases by 50% and heart rate by about 20 beats per minute. Despite the increase in cardiac output, there is an overall decrease in blood pressure.

This is primarily due to smooth muscle relaxation of blood vessel walls caused by relaxin and progesterone (5,6). This smooth muscle relaxation can produce postural hypotension, slow down peristalsis in the gut affecting digestion and even affect bladder tone.

The role of relaxin during pregnancy is not clear, and is beyond the scope of this discourse. Suffice to say that the theory that it stretches ligaments to facilitate foetal descent and exit is not completely satisfactory, not least because peak levels occur at 12 weeks (7).

The effects of these issues as well as changes in hormone levels and a growing foetus mean that these changes vary as time progresses. Giving the woman advice as to what she could expect and how to cope with this can be very helpful.

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Pregnancy is an exciting but anxious time for many women. Here Rachele Quested helps make sense of the latest research and brings a common sense approach to pre and post- natal exercise.

Addressing biomechanical changes during pregnancy The changes that occur in muscle balance, control and posture during pregnancy are generally caused by the foetus moving in a ventral direction as it grows, moving the centre of gravity forwards and changing the overall equilibrium of the spine (8). Part of a fitness professional’s assessment must

take into account how a woman’s body adapts to this. Muscle and ligament length tension relationships alter as

a consequence. The abdominals lengthen, the pelvic floor

has to deal with increased weight and glutei inhibition produces the characteristic waddling gait in late pregnancy as the body problem-solves and widens the base of support to cope (9).

Training balance and control, such as that developed with Pilates training, can be very helpful throughout pregnancy. This can help counteract the negative influence of some of these changes, assist in general activities of daily living (ADLs) as well as exercise and possibly helping with pain syndromes.

What are the key benefits of exercise during pregnancy? The Royal College of Obstetrics and

The REPs Journal 2010;18(September):18-20