Hip pain

Hip pain during pregnancy: Causes and mechanisms

Hip pain, especially when it worsens at night and disrupts sleep, is a common complaint among expectant mothers in the second half of pregnancy. This discomfort can range from a mild, dull ache to a sharp pain that makes walking difficult. The causes of this condition are complex and related to your body’s preparation for labor.

Main causes of hip pain

• Effect of the hormone relaxin. This hormone softens the ligaments and joints of the pelvic girdle, including the sacroiliac joints and the pubic symphysis. This increased flexibility is necessary for childbirth, but it also makes the joints less stable. The muscles around the hips and buttocks have to work harder to stabilize the pelvis, leading to overuse and pain.
• Pressure of the uterus on the sciatic nerve (Sciatica). The growing uterus can compress the sciatic nerve—the largest nerve in the body, which runs from the lower back through the buttocks to the legs. This causes sciatica, pain that may start in the lower back or buttock and radiate along the back or side of the thigh.
• Weight gain and posture changes. Additional weight places direct load on the hip joints. Moreover, the shift in the center of gravity forces you to alter your gait (the so‑called “waddling gait”), which can also lead to hip pain and pelvic pain.
• Sleeping position. Doctors recommend sleeping on the side, preferably the left, for better circulation. However, prolonged lying on one side creates direct pressure on the hip joint, which can cause pain, especially at night. More details are in the article "Sleep during pregnancy".