Women's Back Pain Has Different Causes Than Men's - Addressing Pelvic, Hormonal, and Muscular Factors

Women Report Back Pain More Often Than Men

In Japan's 2022 Comprehensive Survey of Living Conditions, conducted by the Ministry of Health, Labour and Welfare, the rate of people reporting low back pain was 91.6 per 1,000 men and 111.9 per 1,000 women, ranking first among all reported symptoms for both sexes. The figure for women is about 20 percent higher. This is not simply a matter of women being more sensitive to pain. Women have several causes of back pain that men do not.

Structural differences in the pelvis, hormonal fluctuations across the menstrual cycle, the physical changes of pregnancy and childbirth, and comparatively lower muscle strength. These factors act in combination and shape patterns of back pain specific to women. Applying advice written for men has only limited effect precisely because the causes are different.

Pelvic Structure Gives Rise to Back Pain

The Female Pelvis Is Wider and Shallower

Adapted for childbirth, the female pelvis is wider and shallower than the male pelvis. That structure is an advantage for delivery but a disadvantage mechanically. A wider pelvis increases the inward slant of the femur running from the hip joint to the knee. This slant, known as the Q-angle, was originally used as a measure for assessing load on the knee, and how much it affects the lower back is not known. Still, since both the width of the pelvis and the position of the center of gravity differ from men, it is hard to imagine that the muscles around the pelvis are used in exactly the same way.

Mobility of the Sacroiliac Joint

The sacroiliac joints (the joints at the back of the pelvis) in women are often described as more mobile than in men. The reasoning is that this property is needed for the pelvis to widen during childbirth, and that to the same degree it can show up as instability in daily life and lead to back pain. During pregnancy, the ligaments around the pelvis loosen under the influence of a hormone called relaxin. The same explanation is sometimes applied to the premenstrual phase, but a study published in 2007 found that blood levels of relaxin stayed roughly constant through the cycle, including around ovulation and the luteal phase, and were not swayed by the fluctuations of other sex hormones. Explaining premenstrual back discomfort by relaxin does not hold up.

Menstrual-Related Back Pain

Pain Caused by Prostaglandins

Back pain during menstruation is caused by prostaglandins secreted from the uterine lining. Prostaglandins serve to contract the uterus and expel menstrual blood, but when secreted in excess they also act on the tissue around the uterus, producing a dull ache in the lower back and pain in the lower abdomen. The amount of prostaglandin produced varies from person to person, and those with heavier menstrual pain tend to have stronger back pain as well.

Premenstrual Heaviness in the Lower Back

Many people find their hands, feet, and face swell more easily before menstruation, and it is known that the body's fluid balance is affected by hormonal fluctuations. Which hormone works in which way to cause that swelling, however, has not been settled. The explanation that fluid accumulates in the intervertebral discs and makes the lower back feel heavy is also common, but it is not a verified mechanism. The sensation of a heavy, sluggish lower back before menstruation is something many people report, and it is reasonable to think that changes in how pain is perceived and a breakdown in posture are layered on top of the hormonal shifts.

The Close Relationship Between Swayback and Back Pain

Why Swayback Is Common in Women

Swayback (excessive lumbar lordosis) is said to be common in women. The causes are mixed: habitual wear of high-heeled shoes, the lingering shift in center of gravity from pregnancy, weak abdominal muscles, and a tendency toward anterior pelvic tilt. In a swayback posture, pressure on the facet joints of the lumbar spine is easily distributed unevenly. That said, the degree of curve in the lower back and the presence of pain do not line up neatly, and some people with a pronounced curve have no pain at all. Rather than treating posture itself as the enemy, it is more practical to build a state in which the core and gluteal muscles described below can work and support the curve of the lower back.

A Self-Check for Swayback

Stand with your back against a wall, touching the back of your head, your shoulder blades, your buttocks, and your heels to it. If more than one palm's thickness fits between your lower back and the wall in that position, swayback is likely. Ideally, the gap is just barely wide enough for a palm.

Protecting Your Back with Core Training

Activating the Transverse Abdominis

The transverse abdominis is the deepest muscle of the abdomen, and it stabilizes the lumbar spine as a natural corset. When it is weak, the lumbar spine becomes unstable and the load on the discs and facet joints increases. The draw-in (hollowing the belly) is the most basic exercise for training the transverse abdominis selectively. Lie on your back with your knees bent, exhale while drawing your navel toward your spine, and hold for 10 seconds. Do 10 repetitions for 3 sets, every day.

Strengthening the Glutes

The gluteal muscles stabilize the pelvis and distribute load away from the lumbar spine, which makes them important. When sitting for long hours at a desk weakens the gluteal muscles, the burden on the lower back increases. Hip lifts (raising the hips while lying on your back) and clamshells (opening and closing the knees while lying on your side) are gluteal exercises that are easy to do at home.

Stretches for Daily Life

Iliopsoas Stretch

When the iliopsoas (the muscle at the front of the hip joint) shortens, the pelvis tilts forward and swayback worsens. From a half-kneeling position, stretch the front of the hip on the rear-leg side. Hold for 30 seconds, 3 times on each side. Doing it during breaks from desk work is effective.

Piriformis Stretch

The piriformis is a muscle deep in the buttock, and when it stiffens it compresses the sciatic nerve, producing pain or numbness from the buttock down the back of the thigh (piriformis syndrome). Lie on your back, rest one ankle on the opposite knee, then hold the thigh of the lower leg with both hands and draw it toward your chest. Hold for 30 seconds, 3 times on each side.

Correcting a Rounded Back and Swayback

On all fours, exhale as you round your back (cat pose) and inhale as you arch it (cow pose). Repeating this movement 10 times improves mobility of the lumbar spine and eases tension in the surrounding muscles. Doing it after waking and before bed is ideal.

Dangerous Back Pain That Needs Medical Care

Most back pain is a musculoskeletal problem and can be handled with better daily habits and exercise. If any of the following apply, however, see a medical institution promptly: strong pain even at rest (especially at night), numbness or weakness in the legs, trouble with urination or bowel movements, accompanying fever, or rapid weight loss. These may be signs of conditions requiring specialist treatment, such as a herniated disc, spinal canal stenosis, an infection, or a tumor. If back pain does not improve for four weeks or more, a visit to an orthopedic clinic is also advisable.