What usually causes itStrong evidence
Numbness, tingling, burning or aching in the thumb, index and middle fingers and part of the ring finger, often worse at night or first thing in the morning, is typical of carpal tunnel syndrome, where the median nerve is squeezed at the wrist. In a survey of 2,466 Swedish adults, 14.4% had pain, numbness or tingling in that part of the hand, and 3.8% had clinically certain carpal tunnel syndrome. It is more common in women and older people, in pregnancy, and with diabetes, thyroid problems, arthritis, a past wrist fracture and work that involves a lot of repetitive or forceful hand use.
Other nerves can wake you too. Tingling in the ring and little fingers, worse with the elbow bent, is usually the ulnar nerve at the elbow. A trapped nerve in the neck sends a band of pain, pins and needles or numbness down one arm into the hand, sometimes without neck pain, and both hands numb and clumsy with unsteady walking can be pressure on the spinal cord in the neck. Burning or numbness in both hands and both feet is usually nerve damage (peripheral neuropathy); thoracic outlet syndrome, which is rare, causes pins and needles that can wake you; and in a series of 25 people, a wrist that wouldn't lift after sleeping with the arm over a chair or under a pillow was a squeezed radial nerve.
Sources 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11
The tendons, the joints and other causesStrong evidence
Pain on the thumb side of the wrist, worse moving the thumb or lifting with the thumb up, is often De Quervain's tenosynovitis, which is common in pregnancy and in the weeks after a birth. Osteoarthritis brings more pain and stiffness after the joints have been still, often at the base of the thumb or in the finger joints. Rheumatoid arthritis causes warm, swollen, stiff joints, often in both hands, with morning stiffness that usually lasts longer than 30 minutes, and the National Institute for Health and Care Excellence (NICE) asks for an urgent referral when the small joints of the hands are affected.
Gout causes a sudden, very painful, hot, red, swollen joint: in 724 people, attacks were 2.36 times as likely between midnight and 8am as in the daytime. A ganglion is a smooth lump on the wrist that is often painless and may ache with use; no source we read links ganglions with night pain. After a fall, a wrist that is very painful, swollen or out of shape may be broken.
Sources 12, 13, 14, 15, 16, 17, 18, 19
Why it's worse at night: what's knownEmerging evidence
Many people sleep with their wrists bent, US orthopaedic surgeons say, and NHS inform says a splint at night stops you bending your wrist while you sleep, a position that can squash the nerve. In a laboratory study of 15 people with carpal tunnel syndrome, the pressure in the tunnel was 32 millimetres of mercury with the wrist straight, 94 with it fully bent and 110 fully bent back (2.5, 31 and 30 in 12 people without it). In another, the pressure was lowest with the wrist close to straight. In a survey of 396 people, sleeping with the wrist bent went with more frequent pins and needles at night.
Elbows and necks bend in bed too: bending the elbow provokes the ulnar nerve, and sleep was disturbed in 56.5% of 186 people with a trapped nerve in the neck. In pregnancy, carpal tunnel symptoms went with fluid retention; that fluid gathering in the hands overnight makes things worse is a common explanation, but no study we read measured it. Osteoarthritis aches more after rest, and 81% of 123 people with hip or knee osteoarthritis had night pain that came and went, but no study we read measured night pain in hand arthritis, so that figure is borrowed.
Sources 4, 2, 20, 21, 22, 6, 23, 24, 25
Pain, sleep and the body clockEmerging evidence
Sleep and pain affect each other: in studies that follow people over time, sleep problems predict new and worse long-lasting pain more strongly than pain predicts poor sleep, a review found. In a laboratory study of healthy volunteers kept awake under controlled conditions, pain sensitivity followed a daily rhythm, highest in the middle of the night. Neither study was in people with hand pain, so applying them here is our inference. The NHS's sleep habits, and talking therapy for insomnia that lasts, are the tools for the sleep side.
Sources 26, 27, 28
Pregnancy and the weeks after a birthMixed evidence
Of 639 pregnant Dutch women, 219 (34%) reported carpal tunnel symptoms, more after 32 weeks and with fluid retention, and the symptoms went with sleeping problems. Across studies, 31% to 62% of pregnant women had it diagnosed from their symptoms and 7% to 43% on nerve tests.
How long it lasts is less clear. The NHS says carpal tunnel syndrome sometimes gets better by itself, particularly if pregnancy is the cause, but a review found symptoms still there in more than half of women a year after the birth and in about 30% at 3 years. Gradual swelling of the fingers is common in pregnancy; sudden swelling of the face, hands or feet with a severe headache or problems with your vision is a pre-eclampsia warning sign. De Quervain's is also common in the weeks after a birth.
Sources 24, 29, 1, 30, 31, 12
When night symptoms need checkingStrong evidence
The reassuring pattern, in our reading of the sources: tingling in the thumb-side fingers that wakes you and eases when you shake your hand, or pins and needles that go within minutes once the weight is off your arm. These patterns need help: weakness or numbness in one arm with a drooping face (999, even if it passes); both hands clumsy with unsteady walking (the same day); numbness or weakness that is getting worse; numbness that is constant, a weak thumb or the muscle at its base looking thinner (a GP soon, because untreated carpal tunnel syndrome can cause permanent nerve damage); and constant bone pain at night.
On its own, night pain is a weak sign: at a back pain clinic, 213 of 482 people had night pain, 90 of them every night, and none was found to have a serious disease. That study was in back pain, not hand pain.
Sources 32, 8, 7, 1, 3, 4, 33, 34, 35
Tests and scansEmerging evidence
Carpal tunnel syndrome is usually diagnosed from your symptoms and an examination of the hand, and often the neck. NHS inform says nerve conduction tests can be done but aren't essential, and blood tests can look for a condition that adds to it; ultrasound or magnetic resonance imaging (MRI) is used less often. Suspected rheumatoid arthritis needs blood tests and X-rays, which mustn't delay an urgent referral, and gout can be confirmed with a blood test or fluid from the joint. A wrist that won't lift after sleeping on the arm is diagnosed from the examination, with nerve tests if it doesn't start to recover, and clumsy hands with unsteady walking need an urgent assessment.
Sources 1, 2, 3, 15, 16, 11, 8
How it usually goesEmerging evidence
Carpal tunnel syndrome can settle by itself, especially in pregnancy, but often doesn't. In a UK trial of a night splint or a steroid injection, 16% of the splint group and 22% of the injection group had had surgery after 2 years. After surgery, night symptoms improve dramatically for most people within the first week or so, US orthopaedic surgeons say, and sleep scores improve within 1 to 3 months.
With mild or moderate ulnar nerve symptoms, 89.5% of people in a Swedish trial had improved at 6 months after advice about positions. A wrist that won't lift after sleeping on the arm started to recover after about 2.4 weeks on average. No one can promise a timescale.
Sources 1, 29, 36, 4, 37, 38, 11