Sciatica during pregnancy is most often caused by the combined effects of weight gain, postural shifts, and hormone-driven loosening of pelvic ligaments, all of which can put pressure on the sciatic nerve. About 22% of pregnant women experience sciatica at some point during their pregnancy, and it becomes more common as the baby grows larger in the third trimester.
How Pregnancy Puts Pressure on the Sciatic Nerve
The sciatic nerve is the longest nerve in your body, running from your lower back through your hips and buttocks and down each leg. During pregnancy, several things happen at once that can irritate or compress this nerve.
As your uterus expands and your baby gains weight, the added load presses directly on structures in your lower back and pelvis. Your growing belly also pulls your center of gravity forward, which forces your spine to curve more dramatically in the lower back to keep you balanced. This exaggerated curve, combined with the extra weight, narrows the spaces where the sciatic nerve exits the spine and travels through the pelvis.
On top of that mechanical pressure, your body produces a hormone called relaxin throughout pregnancy. Relaxin loosens the muscles, ligaments, and joints around your pelvis, back, and abdomen to prepare your body for delivery. While this loosening is necessary for childbirth, it can make your pelvic joints less stable. That instability allows bones and soft tissues to shift in ways that irritate the sciatic nerve. Relaxin can also contribute to pelvic girdle pain, a related but distinct condition that sometimes gets confused with sciatica.
The Baby’s Position Matters
Later in pregnancy, your baby’s specific position inside the uterus can make sciatica better or worse. When the baby settles lower into the pelvis or shifts to a position where their head or body rests against the sciatic nerve, pain can flare suddenly. This is why many women notice sciatica appearing or worsening in the third trimester, and why the pain sometimes changes from day to day as the baby moves.
Disc Herniation Is Rare but Possible
True disc herniation, where a cushioning disc between vertebrae bulges and presses on a nerve root, is an extremely uncommon cause of sciatica in pregnancy. One study found an incidence of just 0.1 per 100,000 pregnancies, which is lower than the rate in non-pregnant women of the same age. The vast majority of pregnancy-related sciatica comes from the postural and hormonal changes described above, not from structural disc problems.
Sciatica vs. Pelvic Girdle Pain
Many women assume any pain in the lower back or buttocks during pregnancy is sciatica, but posterior pelvic girdle pain is actually more common and feels different. With sciatica, pain typically follows a clear path: it starts in the lower back or buttock and shoots down one leg, sometimes reaching the foot. You can usually point to where it hurts.
Pelvic girdle pain is harder to pin down. It produces a stabbing, dull, or burning sensation in the back of the pelvis that can spread to the buttock, groin, and back of the thigh. The location and character of the pain often shifts as the pregnancy progresses, and many women describe it as impossible to locate precisely. If your pain stays in the pelvic area without traveling down your leg in a defined line, pelvic girdle pain is the more likely explanation.
Stretches That Relieve Sciatic Pain
Physical therapy, massage, and targeted stretching are the primary ways to manage sciatica during pregnancy. Several stretches specifically help by releasing tension in the muscles around the sciatic nerve.
A seated piriformis stretch is one of the simplest. Sit in a chair with your feet flat on the floor, then place the ankle of your affected side on the opposite knee. Keeping your back straight, lean forward until you feel a stretch through your buttock. Hold for 30 seconds and repeat throughout the day. The piriformis muscle sits deep in the buttock directly over the sciatic nerve, and when it tightens, it can compress the nerve and mimic or worsen sciatica symptoms.
A table stretch works well for the lower back. Stand facing a table with your feet slightly wider than your hips, then lean forward with your hands on the table, keeping your arms straight and your back flat. Pull your hips away from the table until you feel a stretch in your lower back and the backs of your legs. Gently moving your hips side to side deepens the stretch. Hold for 30 seconds to a minute.
A modified pigeon pose targets the hip rotators. Start on your hands and knees, slide one knee forward between your hands, and extend the opposite leg back. Place a rolled towel or yoga block under the hip of your forward leg to make room for your belly and reduce strain. Lean forward slowly, using a pillow under your head and arms for support. Hold for about a minute on each side.
Non-weight-bearing exercise like swimming can also help by taking pressure off the spine and pelvis while keeping muscles active.
Support Belts and Pain Relief
Maternity support belts (sometimes called belly bands) can reduce sciatic pain by redistributing the weight of your baby across your back and abdomen. This takes pressure off the pelvic ligaments and helps stabilize the sacroiliac joint, the joint at the base of your spine that becomes especially loose during pregnancy due to relaxin. These belts tend to work best during activities like walking, climbing stairs, or standing for long periods.
When Sciatica Becomes an Emergency
In very rare cases, severe nerve compression can affect a bundle of nerves at the base of the spine called the cauda equina. Warning signs include weakness in both legs, numbness in the area where you would sit on a saddle (inner thighs, buttocks, and groin), difficulty urinating or inability to fully empty your bladder, and loss of bowel control. These symptoms require immediate medical attention because permanent nerve damage can result without prompt treatment.
What Happens After Delivery
For most women, sciatica improves within a few weeks to a few months after giving birth. Once the baby is delivered, the direct pressure on the sciatic nerve is relieved, and relaxin levels gradually drop, allowing pelvic ligaments to tighten back up. Recovery can take longer if there was an injury during childbirth, a particularly long or difficult labor, or a pre-existing spinal condition. Women who had back labor, a breech delivery, or significant postural changes during pregnancy may also notice symptoms lingering longer as the body readjusts.