A number of natural biological changes occur in a woman's body during pregnancy that directly affect the musculoskeletal system and can be a potential cause of related problems such as back pain and leg pain. Pregnancy-related changes typically involve the joints and connective tissues, making them loose, supple, and soft. These changes result in increased stress and strain on the spinal and pelvic joints in the lower back and hips. Back pain can develop as early as the first trimester and typically increases as the pregnancy continues.
Typical Features of Low Back Pain During Pregnancy
Back pain affects more than 50% of pregnant women. While it can occur at any time during pregnancy, back pain is usually most severe during the second and third trimesters.
Pregnancy-related symptoms and signs affecting the lumbar region result in decreased overall function and include, but are not limited to:
Pain of varying intensity that begins or flares up during movement or activity, such as sitting, standing, walking, lifting objects, sexual intercourse, bending over.
Sleep disturbances due to pain when turning in bed, insomnia and reduced sleep hours.
Reduced range of motion in the lower back.
Changes in balance and gait pattern, especially in the second and third trimesters.
These changes are often caused by a shift of the center of gravity towards the abdomen. This shift increases the curve of the lower spine and causes the sacrum (the part of the spine that connects the lower back to the hip) to curve backwards slightly. While pregnant women who lead a sedentary lifestyle are at higher risk of experiencing back pain, doing heavy physical work or being active during the day can also lead to back pain symptoms during pregnancy.
Some research shows that women with a high body mass index (BMI) may have a higher risk of developing back pain while pregnant. Back pain that continues after birth is called postpartum back pain. About 72% of women continue to experience postpartum pain in the lower back and pelvis for up to 1 year after giving birth, and in some cases this can last up to several years.
How Pregnancy-Related Changes Can Cause Back Pain
Women generally gain between 7 and 16 kilograms during pregnancy, experience a shift in their weight points, and undergo various hormonal and anatomical changes.
These natural changes increase the pressures and loads on the lower spine and pelvis, contributing to the following changes:
Changes in posture. The growing uterus and increased curvature of the lower spine change the posture of the spine, putting additional loads on the lower back.
Changes in muscle tissue and balance. The paraspinal muscles that support and fix the lumbar region are shortened and unbalanced by excessive stretching of the anterior abdominal muscles.
Discomfort in the sacroiliac joints. A 10-fold increase in the concentration of the relaxant hormone during pregnancy causes softening of the connective tissue in the pelvis and lower back, which leads to discomfort in the sacroiliac joints.
Pressure in the pelvic joint. The pelvis is a stabilizing structure in the lower body that transfers loads from the upper body to the legs. Hormonal changes, changes in posture and gait, and stress on ligamentous structures can cause increased forces on the pelvic joints in pregnant women.
Pressure on the spinal discs. Although rare, approximately one in 10,000 pregnant women (less than 1%) may develop a herniated disc in the lumbar spine due to increased stress on the discs due to simultaneous bodily changes. A herniated disc can irritate, or mechanically compress, a spinal nerve root in the lower back, causing its symptoms to radiate to the thigh, leg, and/or foot.
Transient osteoporosis. Carrying weight can cause temporary osteoporosis in some women, especially in the third trimester. This bone-weakening condition develops suddenly and causes hip pain and reduced range of motion in the hips.
Pre-existing low back conditions such as idiopathic scoliosis, rheumatoid arthritis, and ankylosing spondylitis can worsen during pregnancy and increase pain and other symptoms.
Muscle separation. As the uterus expands, two parallel layers of muscle (rectus abdominis muscles) running from the rib cage to the pubic bone can separate along the middle seam. This separation can worsen back pain.
Stress. Emotional stress can cause muscle tension in the back, which can be felt as back pain or back spasms. You may notice that your back pain increases during the stressful times of your pregnancy.
When to Seek Medical Assistance?
Back pain is often untreated and is considered a normal and inevitable part of pregnancy among women. To make pregnancy as pleasant as possible and delivery easier, back pain must be addressed and managed. Long-lasting low back pain during pregnancy is often a precursor to postpartum back pain. Pregnant women are encouraged to seek appropriate back pain treatment to prevent recurrence of pain in later stages.
Vaginal bleeding, right or left lower abdominal pain, groin pain, fainting sensations, and back pain associated with tarry stools may indicate a ruptured ectopic pregnancy, which is a medical emergency that needs immediate treatment.
Postpartum pain that lasts longer than 6-8 weeks should be treated after delivery to prevent chronic back pain or recurrent back problems. Over time, chronic pain can lead to psychological and psychosocial events that interfere with daily functioning and reduce overall quality of life.
As a general rule, any lower back symptoms should be discussed with a doctor without delay to ensure the safety of the mother and the growing fetus, as these symptoms may indicate an ectopic pregnancy, preterm delivery or infection.
Back Pain Treatments During Pregnancy
There are many things you can do to treat low back pain or make it less frequent and lighter:
Exercising: Regular exercise strengthens muscles and improves flexibility. This can reduce stress on your spine. Safe exercises for most pregnant women include walking, swimming and stationary cycling. Your doctor or physical therapist may recommend exercises to strengthen your back and abdomen.
Heat and cold: Applying heat and cold to your back can help. If your healthcare provider agrees, start by placing cold compresses (such as a bag of ice or frozen vegetables wrapped in a towel) on the painful area for up to 20 minutes several times a day. After two or three days, switch to heat – put a heating pad or hot water bottle on the painful area. Be careful not to apply heat to your abdomen during pregnancy.
Posture: Bending over strains your spine. That's why using proper posture while working, sitting or sleeping is a good move. For example, sleeping on your side with a pillow between your knees will reduce the stress on your back. When sitting at a table, put a rolled up towel or small pillow behind you for support; put your feet on a stool and sit upright with your shoulders back. While standing, pull your hips forward and your shoulders back. You can sit back to make up for your growing belly. Wearing a support belt can also help.
Counseling: If back pain is stress related, talking to a trusted friend or counselor can help.
If you need to pick something up off the ground, use your legs to squat rather than bend over.
Do not wear high heels. Choose low-heeled shoes with good arch support. Remember, you may need to buy a larger shoe size as the hormones loosen the joints.
Do not sleep on your back.
If your back pain persists, you can consult your doctor to see what else you can try. Always consult your doctor before taking pain relievers. In some cases, your doctor may recommend pain relievers or muscle relaxants that are safe during pregnancy.