Causes of Lower Back Pain during Pregnancy

Back pain is a common symptom of pregnancy that as many as 50% to 70% of pregnant women experience. While it most commonly occurs in the later stages of pregnancy as the baby bump grows larger, back pain can also be one of the early signs of pregnancy.

There are two types of back pain that can occur during pregnancy – lumbar pain (lower back pain) and posterior pelvic pain (which is felt below the waistline). Lumbar back pain is generally similar to lower back pain experienced by individuals who are not pregnant.

It has been found that women most at risk for developing back pain are those who are overweight or have a history of back pain prior to becoming pregnant. There are several causes of lower back pain during pregnancy.

1. Hormonal Changes

During pregnancy, the body releases a hormone called relaxin which causes the ligaments in the pelvic area to loosen. This occurs in preparation for child birth to facilitate the passing of the baby through the birth canal. The changes in the joints and loosening of the ligaments in the pelvic area can also affect the back.

Additionally, relaxin doesn’t only act on ligaments in the pelvic area, it also loosens other ligaments in the body – including those along the spine. Loosening of ligaments in the back decreases the stability of the lower back leading to a reduction in support at a time when the back is placed under added stress.

2. Changes in Center of Gravity

As the baby bump grows larger, a woman’s center of gravity will gradually move forwards, causing a change in posture to balance the increasing bump size. Changes in posture and the increasing weight of the bump places strain on the ligaments, back which may lead to back pain.

3. Weight Gain

Just as individuals who experience excessive weight gain can develop back pain, pregnant women are no different. Over the course of nine months, a woman gains as much as 12 to 18kgs – and that is if she follows the recommended guidelines for weight gain during pregnancy. If she is already overweight to begin with, this worsens her risk for developing back pain during pregnancy.

The increased weight from the pregnancy and baby adds to the weight that the back is required to support. As most of the weight is added to the front of the body, it exacerbates the strain on the back. Increased weight gain can also lead to spinal nerve compression – which is yet another cause of back pain.

4. Posture and Activities

Poor posture increases and aggravates back pain because it adds stress to the spine. Failing to utilise correct posture when picking things up can also exacerbate back pain.

Other activities that can escalate back pain include standing for long periods and carrying heavy objects in front, for instance, an older child.

5. Weak Abdominal Muscles

Individuals with back pain are often encouraged to strengthen their abdominal muscles because they help to support the back. During pregnancy, the expanding uterus stretches the abdominal muscles which weaken them. Without the abdominals to stabilise the pelvis, it falls to the back muscles and spine to handle the increasing task of supporting the added weight and changing center of gravity.

6. Stress

There is a strong link between stress and lower back pain. During pregnancy, stress can be increased which may also contribute to lower back pain.

There are many causes of lower back pain during pregnancy – all or some of which may be contributing factors. Most of the causes of lower back pain are the same as those causing lower back pain in regular back pain sufferers – increase weight, weak muscles, stress, and poor posture. Many of these causes can be corrected to help reduce the experience of back pain during pregnancy.