Why nerves get squeezed in pregnancy

The NHS's general explanation of pins and needles is mechanical: it "happens when the blood supply to the nerves is cut off", usually from sitting or lying on part of your body, and "it usually stops when the weight is taken off the body part and your blood supply returns to the nerves".

Pregnancy adds three things to that. You are holding more fluid, so tissues swell inside tunnels that do not stretch. Your posture and centre of gravity shift, changing where load falls on the spine and pelvis. And there is more weight pressing on structures in the pelvis, particularly late on. The result is that a symptom which normally lasts a couple of minutes can become a nightly event.

Most of it resolves after birth. That is the general rule, not a promise about your particular symptom, which is why the sections below are about deciding whether yours needs looking at.

Where it is tells you what it probably is

Hands and fingers, worst at night

Numbness, tingling or aching in the fingers that wakes you, and that you shake out, is the classic pregnancy pattern. It usually comes from swelling inside the wrist pressing on the median nerve. Tommy's lists carpal tunnel syndrome among the common health problems of pregnancy, and it generally settles within a few months of birth. A wrist splint worn at night is the standard first treatment, and it is worth asking for rather than waiting out.

One leg, from the buttock down the back

The NHS describes sciatica as symptoms that "usually affect your bottom and the back of one leg, often including your foot and toes", with "tingling — like pins and needles", numbness and weakness alongside a sharp or burning pain. It adds a line that saves a lot of confusion: "You probably do not have sciatica if you only have back pain." Pain that stays in the back is back pain. Pain and tingling that travel down one leg is a nerve.

Outer thigh, a patch that feels dead or burning

A well-defined patch of numbness or burning on the outside of one thigh, with no weakness and nothing travelling below the knee, is a compressed nerve where it passes under the ligament at the front of the pelvis. It is uncomfortable rather than dangerous, tends to arrive in later pregnancy, and is worth mentioning at your next appointment rather than out of hours.

Feet and legs when you have been still

The NHS's mechanical explanation covers this: weight on a nerve, blood supply reduced, symptoms resolving when you move. Late pregnancy makes it easier to trigger and slower to clear. If it clears within minutes of moving, it is positional.

Pins and needles in several places at once

The NHS lists causes worth ruling out when tingling is widespread or persistent: diabetes, Raynaud's if fingers or toes change colour, hyperventilation if it comes with fast breathing and trembling hands, a trapped nerve in the back or neck, nerve damage, poor diet, and some medicines. Its advice is to see a GP "if you constantly have pins and needles" or "it keeps coming back", and explicitly not to self-diagnose.

The patterns that are not ordinary

The NHS gives a specific emergency list for sciatica-type symptoms. Go to A&E or call 999 if you have:

Sciatica on both sides.
Weakness or numbness in both legs that is severe or getting worse.
Numbness around or under your genitals, or around your bottom.
Difficulty starting to pee, an inability to pee, or loss of control over when you pee.
Not noticing when you need to poo, or being unable to control it.

The NHS's back pain advice for pregnancy repeats the core of it: call 999 or go to A&E if you have back pain and "you lose feeling in one or both of your legs, your bum, or your genitals". These symptoms point to compression of the nerves at the base of the spine, and the outcome depends on how fast it is treated. This is one of the few things in pregnancy where hours genuinely matter.

Separately, numbness or tingling that arrives suddenly on one side of the body, or with weakness in the face or arm, difficulty speaking, or a severe headache, is an emergency call rather than a maternity call.

What helps the ordinary kind

Change position often. The NHS's sciatica advice is to carry on with normal activities as far as you can and specifically "do not sit or lie down for long periods — even if moving hurts, it's not harmful and can help you get better faster".
Sleep on your side with support. A pillow between the knees keeps the pelvis level and takes strain off the lower back.
Splint the wrists at night if the problem is hands.
Keep moving your ankles and feet. The NHS's foot exercises — bend and stretch 30 times, rotate 8 times each way — are recommended for circulation and swelling, and cost nothing.
Ask about physiotherapy. In many areas you can self-refer to NHS musculoskeletal services without going through a GP.

When to call someone

Your local emergency number — 999 in the UK and Ireland, 911 in the US and Canada, 000 in Australia, 111 in New Zealand — for numbness in both legs, numbness around the genitals or bottom, new problems controlling your bladder or bowel, or sudden one-sided weakness (NHS).
Your GP for pins and needles that are constant or keep coming back, or that come with symptoms elsewhere (NHS).
Your midwife for hand or wrist symptoms interfering with sleep or with using your hands, and for anything that is getting steadily worse rather than staying the same.
Your maternity unit immediately if tingling or numbness arrives with a severe headache, blurred vision, sudden swelling or upper tummy pain — that combination belongs to the pre-eclampsia list (HSE, NHS).

The short version

Most pregnancy tingling is a squeezed nerve and settles after birth. Hands at night is usually carpal tunnel; one leg from the buttock down is usually sciatica; a numb patch on the outer thigh is usually a trapped nerve at the pelvis. Numbness in both legs, or anywhere near the saddle area, with bladder or bowel changes, is an emergency and not a pregnancy symptom at all.

Numbness and Tingling in Pregnancy