Sciatica in pregnancy is common, usually mechanical, and usually improves after birth. It also carries the one genuine surgical emergency in this A–Z, which is why the warning signs come first and are written in plain words rather than by name.
Go to an emergency department or call emergency services immediately if you have any of: pain or weakness in both legs; numbness or altered sensation around the saddle area — inner thighs, buttocks, genitals or back passage; difficulty passing urine, not feeling the flow, or losing control of your bladder or bowel. This is compression of the nerve bundle at the base of the spine. It is rare, it does not wait, and acting within hours is what prevents permanent damage.
The short answer: shooting pain from the buttock down one leg, often with tingling or numbness in the same line, made worse by sitting and by standing up. Keep moving in short bouts rather than resting completely, side-lie with a pillow between the knees, and ask for a physiotherapy referral early. Much of what is called sciatica in pregnancy is pelvic girdle pain instead, and the two are treated differently. Paracetamol yes, ibuprofen not after 20 weeks.
Why it happens
The sciatic nerve is the largest in the body, formed from nerve roots in the lower spine and running through the buttock and down the back of the leg. Pregnancy affects it in two ways. Relaxin softens the ligaments of the lumbar spine and pelvis, allowing more movement and altering how load is distributed; and the changing posture increases the curve of the lower back, which narrows the spaces the nerve roots pass through. The piriformis muscle in the buttock, which the nerve runs beneath or through, also tightens as gait changes.
Note what is usually not the cause: the baby's head pressing directly on the nerve. That explanation is common and rarely accurate — the mechanism is spinal and muscular, which is why treatment works on the spine and muscles.
Sciatica or pelvic girdle pain?
| Sciatica | Pelvic girdle pain | |
|---|---|---|
| Path | Travels down the leg, sometimes past the knee | Stays in the pubic bone, groin, hip or back of pelvis |
| Sensation | Burning or shooting, with pins and needles or numbness | Sharp mechanical pain, sometimes clicking |
| Worse on | Sitting, standing up, coughing, sneezing | Stairs, getting out of a car, rolling over, standing on one leg |
| Relieved by | Walking, changing position, lying on the unaffected side | Symmetrical movement, keeping the knees together |
Both are treated by physiotherapy and both are worth a referral. Getting the label right matters because the exercises differ, and doing PGP exercises for sciatica wastes weeks you would rather not waste.
What helps
- Do not rest completely. Short frequent bouts of gentle movement beat lying still, and prolonged sitting is usually the single worst position.
- Side-lie on the unaffected side with a pillow between the knees and one supporting the bump.
- Warmth — a warm bath or a covered heat pack on the buttock and lower back.
- Ask for physiotherapy early. Midwife referral or self-referral where available.
- Avoid lifting and twisting together, and get up from sitting by sliding forward first rather than hinging at the waist.
- Paracetamol at the lowest effective dose. Ibuprofen is avoided after 20 weeks.
Also call the same day — not an emergency, but not next week either — for progressive weakness in one leg, a foot that drags or catches when you walk, numbness that is spreading, or pain that is not controlled by paracetamol and is preventing sleep entirely.
Sciatica in pregnancy — at a glance
Relaxin softens the lumbar and pelvic ligaments while the deepened curve of the lower back narrows the spaces the nerve roots pass through, and a tightening piriformis muscle in the buttock adds to it — the baby's head pressing on the nerve is a common explanation and rarely the actual one. The presentation is sharp or burning pain travelling from the buttock down one leg, often past the knee, with pins and needles or numbness in the same line, worse on sitting, standing up, coughing and sneezing. Much of what is labelled sciatica in pregnancy is pelvic girdle pain instead, which stays in the pelvis and is provoked by asymmetrical movements; the distinction matters because the physiotherapy differs. Management is short frequent movement rather than rest, side-lying with a pillow between the knees, warmth, an early physiotherapy referral, and paracetamol with ibuprofen avoided after 20 weeks. Pain or weakness in both legs, saddle numbness, or any change in bladder or bowel control is compression of the nerve bundle at the base of the spine and needs emergency assessment within hours.
Inside Baby Novum: the daily check-in records pain alongside activity and sleep, which is precisely what a physiotherapist asks for at a first appointment — what makes it worse, what time of day, how long it has been going on — and precisely what nobody reconstructs accurately from memory. Encrypted on the device, no account, no server copy.
Frequently Asked Questions
What does sciatica in pregnancy feel like?
A sharp or burning pain that starts in the buttock or lower back and travels down one leg, sometimes past the knee to the foot, often with pins and needles or numbness along the same path. It is usually one-sided. Sitting, standing up from sitting, coughing and sneezing typically make it worse.
Is it definitely sciatica?
Often not. True sciatica means irritation of the sciatic nerve, and the pain travels down the leg in a line. A great deal of what gets called sciatica in pregnancy is actually pelvic girdle pain, which sits in the buttock and hip, is provoked by asymmetrical movements like stairs and getting out of a car, and does not shoot down the leg. The distinction matters because the physiotherapy is different.
What relieves sciatica in pregnancy?
Keep moving in short bouts rather than resting completely — prolonged sitting is usually the worst thing for it. Side-lying with a pillow between the knees, warmth, and gentle stretches for the piriformis and lower back. Physiotherapy is the main treatment, and it is worth asking for a referral early. Paracetamol is the usual painkiller; ibuprofen is avoided after 20 weeks.
When is leg pain in pregnancy an emergency?
When it involves both legs, or when there is numbness around the saddle area — the inner thighs, buttocks and genitals — or any change in bladder or bowel control, including difficulty starting to pass urine or not feeling it when you do. That is compression of the nerves at the base of the spine and it needs emergency assessment the same hour, not the same day. Permanent damage is prevented by acting quickly.
Will sciatica affect the birth or go away afterwards?
It does not prevent a normal birth, though it is worth noting in your birth plan so positions can be chosen around it. Most pregnancy-related sciatica improves substantially after birth as the mechanical load and the hormonal ligament laxity resolve. Symptoms that persist beyond the early postnatal weeks are worth following up rather than waiting out.