Backache in pregnancy is a common problem faced by almost all pregnant women. A pregnant woman’s pelvis has to expand at the time of birth to allow the baby through. To facilitate this expansion, the ligaments that normally hold the joints of the pelvis (and other parts of the body) together become slightly softer and more elastic which makes them more susceptible to strain. The joints of the spine are particularly at risk because the expanding uterus shifts the centre of balance and changes posture. Standing for any length of time is likely to impose unusual stresses on the back, and this strains the supporting ligaments and results in backache.
Slight movements of the vertebrae, one on the other, can cause nerves to be pinched and result in pain such as sciatica. This nerve pinching is further aggravated by the retention of fluid in the whole body, which causes the nerves to be slightly swollen and therefore more easily pinched.
The best way to reduce the likelihood of backache is not to gain weight excessively and to avoid all heavy lifting. At antenatal classes, physiotherapists show the correct way to lift, and teach exercises to help relieve the backache.