What's Happening
One nerve — from your lower back to your foot — under pressure.
The sciatic nerve is the longest nerve in the body, running from the lower lumbar spine, through the piriformis muscle in the buttock, and down the back of the leg to the foot. When something compresses or irritates it, the result is unmistakable — a sharp, shooting, burning, or electric sensation that follows that nerve pathway.
During Pregnancy, sciatica most commonly develops because of two overlapping changes. The first is the postural shift caused by your growing belly — as your lumbar spine curves more sharply inward, the vertebrae and discs at L4 and L5 can compress the nerve roots that form the sciatic nerve. The second is that the piriformis muscle, which the sciatic nerve passes through or next to, tightens in response to pelvic instability caused by relaxin — which can compress the nerve directly.
"Many moms describe sciatic pain as feeling like an electric shock from their hip to their foot. Others describe it as a deep, persistent ache through the buttock. Both are sciatic nerve irritation — just at different points along the pathway."
Why It Happens When It Does
The factors that trigger and intensify it.
Third trimester weight and positioning. As baby grows and moves lower into the pelvis in preparation for birth, the pressure on the lumbar spine and piriformis muscle increases. This is why sciatica often begins or worsens in the final weeks of Pregnancy.
Prolonged sitting. Sitting compresses the lumbar discs and tightens the piriformis simultaneously. Many moms notice the worst episodes after long periods of sitting — in the car, at a desk, or on the couch.
Asymmetrical movement. Activities that shift weight to one side — climbing stairs, stepping up into a car, even walking unevenly — can suddenly compress the nerve and trigger a sharp episode.
SI joint instability. When the sacroiliac joint is unstable, the body compensates with muscle tension throughout the hip and buttock — including the piriformis. This compensatory tension is a major driver of Pregnancy sciatica.
What Actually Helps
Approaches that address the nerve, the joint, and the muscle.
SI Joint Stabilization
Reducing the instability at the sacroiliac joint often reduces the compensatory piriformis tension that compresses the nerve. Targeted SI joint support — not just belly support — is the most effective structural intervention.
Piriformis Stretching
Gentle piriformis stretches — a figure-four stretch, seated or lying down — can release the muscle tension that compresses the sciatic nerve. These are safe in Pregnancy and can provide significant immediate relief.
Positioning During Sleep
Sleeping on the non-affected side with a pillow between the knees reduces piriformis tension overnight and often dramatically reduces morning symptoms. A pregnancy pillow that supports the belly reduces lumbar strain simultaneously.
What To Avoid
Prolonged sitting without lumbar support, carrying weight on the affected side, and any movement that requires rotating the hip outward suddenly. These positions directly compress the piriformis against the sciatic nerve.
Talk With Jenn About Your Sciatica
Tell Jenn where you feel it and when it's worst — she'll explain what's driving it and which Body After Baby support addresses the root cause.
Talk With Jenn →Postpartum
After delivery — when sciatica often persists longer than expected.
Sciatica frequently resolves after delivery as the mechanical pressure from the uterus is removed. However, for many moms it persists — or new episodes emerge — in the Postpartum period.
The continued presence of relaxin in the body keeps the SI joint and surrounding ligaments loose for months after delivery. Combined with the asymmetrical demands of carrying, feeding, and caring for a newborn, the piriformis and lumbar spine remain vulnerable to the same irritation pattern that caused Pregnancy sciatica.
If sciatica persists beyond six to eight weeks Postpartum, a women's health physical therapist can assess whether the origin is piriformis tightness, SI joint instability, or lumbar disc involvement — and treat accordingly.