Training Considerations During Pregnancy: Part 3 Common Anatomical Considerations

Common anatomical considerations during pregnancy include weight gain and associated shifting of the centre of gravity, postural changes, and joint laxity due to hormonal changes.

Weight Gain and Shifting Centre of Gravity

The rapid weight gain and altered weight distribution typical in pregnancy leads to a number of postural and biomechanical changes in the mother’s body. Whilst the pregnancy obviously affects posture, posture can also be affected by employment demands, daily activities and poor habits. These can all place stress on the skeletal system, vertebrae and the pelvic girdle.

As the foetus develops the mother’s centre of gravity shifts forwards and upwards. This growing abdominal region and the resultant changes in the centre of gravity of the mother can have a marked effect on her balance and on her ability to rapidly change direction. This shift in centre of gravity also destabilises the mother’s core and increases the risk of tripping and falling.

Posture and pregnancy

At the same time increased lumbar lordosis increases anterior slide of the lumbar vertebrae thus increasing the risk of intravertebral disc pressure and hence the risk of localised back pain.

Increased tightness of the musculature surrounding the spine along with increased thoracic kyphosis and an increase in breast size can increase round shoulder appearance in the mother. This increased breast size is due to increases in HPL (Human Placental Lactogen) hormones. As the mother’s shoulders begin to round the shoulder abductors are affected and compressive forces in the shoulder are increased.

This rounding of the shoulders also causes the mother’s head to move forward, leading to additional stress on the posterior neck musculature. This will also cause tightness in the upper trapezius. This may increase intravertebral pressure in the cervical region and cause the mother to experience headaches.

The trainer’s focus should be on instructing the mother in proper postural habits to minimise strain, especially on the back. At all times the trainer should be concentrating on decreasing the risk of injury.

Joint laxity

The mother’s many hormonal changes may cause joint laxity and hyper-mobility. There is an increased laxity in joints due to the release of relaxin by the placenta. This is designed to increase laxity in the pelvic ligaments and pubic symphysis, thus widening and allowing greater flexibility of the birthing canal.

This laxity can lead to a waddling gate and increase the sheering effects on the pelvis joints during movement. The effect of relaxin also has a global effect on all the joints of the body, increasing their flexibility and thus decreasing the stability of the joint. This decreased stability increases the susceptibility to injury during gross or compound movements. The mother may experience significant laxity changes between the first and second baby.