Carpal Tunnel Syndrome in Pregnancy

Carpal tunnel syndrome in pregnancy is compression of the median nerve at the wrist, occurring or worsening in pregnancy, caused by oedema and fluid retention in the carpal tunnel, usually in the second and third trimesters, producing nocturnal tingling, numbness and pain in the thumb, index, middle and radial half of the ring finger.

• Symptoms occur in about 30 to 60 percent of pregnant women, with nerve conduction abnormalities in up to 60 percent; clinical syndrome requiring treatment in about 2 to 35 percent.
• Risk factors: pre-existing carpal tunnel syndrome, obesity, excessive weight gain, gestational hypertension and pre-eclampsia, gestational diabetes, hypothyroidism, repetitive wrist work, primigravida, and multiple pregnancy.
• It is usually bilateral, worse in the dominant hand, and most cases resolve within weeks to 3 months of delivery.
• Persistence beyond 3 to 12 months postpartum occurs in about 10 to 30 percent, particularly with breastfeeding, and prior symptoms.

• Burning, tingling and numbness in the thumb, index, middle and half of the ring finger, often waking the patient at night and relieved by shaking the hand (flick sign), worse in the morning and with gripping, driving, typing or holding a phone.
• Weak grip, dropping objects, clumsiness; pain may extend to the forearm or shoulder.
• Signs: Tinel sign (tapping over the median nerve at the wrist), Phalen test (wrist flexion for 60 seconds), Durkan carpal compression test (pressure for 30 seconds), reduced sensation in median distribution sparing the thenar eminence, thenar wasting and weak thumb abduction in advanced cases.
• Check blood pressure and urine protein for pre-eclampsia, check for generalised oedema, face or hand swelling.
• Red flags: severe constant numbness, thenar atrophy, weakness (urgent referral); bilateral generalised swelling with hypertension, headache and visual symptoms (pre-eclampsia).

• Clinical diagnosis; nerve conduction studies are rarely required in pregnancy but can confirm severity when diagnosis is uncertain, or when surgery is planned.
• Check blood pressure, urine protein, fasting or random glucose (and oral glucose tolerance test if indicated), TSH, and FBC (anaemia, B12 deficiency).
• Cervical spine examination to exclude cervical radiculopathy; consider thoracic outlet syndrome and de Quervain tenosynovitis, which is also common in pregnancy and postpartum.
• Differentials: cervical radiculopathy, pronator syndrome, ulnar neuropathy, peripheral neuropathy (including from vitamin B12 or B6 deficiency), diabetic neuropathy, acroparaesthesia of pregnancy, de Quervain tenosynovitis, and Raynaud phenomenon.

Conservative (first line; most women improve)

• Neutral position wrist splint (wrist at 0 to 5 degrees) worn at night and during activities that provoke symptoms, for at least 4 weeks and continued through the pregnancy as needed; improves symptoms in about 70 to 80 percent.
• Activity modification: avoid prolonged wrist flexion and repetitive gripping, ergonomic keyboard and mouse positioning, frequent breaks, avoid sleeping on the hands.
• Elevate the hands at night; cold compress; hand and median nerve gliding exercises; avoid excessive salt and fluid retention.
• Treat the cause of oedema when present (hypertension, pre-eclampsia).
• Analgesia: paracetamol 1 g orally up to four times daily (maximum 4 g daily). Avoid NSAIDs in pregnancy, particularly from 20 weeks, because of fetal renal effects and ductus arteriosus constriction.
• Oral vitamin B6 (pyridoxine) 50 to 100 mg daily has weak evidence; do not exceed 100 mg daily because of sensory neuropathy.

Corticosteroid injection (for persistent or moderate symptoms)

• Methylprednisolone acetate 40 mg (or triamcinolone 20 to 40 mg) with lidocaine 1 percent 1 mL injected into the carpal tunnel, ulnar to the palmaris longus tendon, with or without ultrasound; relief in about 70 to 80 percent for weeks to months; can be repeated once after 6 to 12 weeks. Safe in pregnancy when given locally in low dose; monitor glucose in gestational diabetes. Avoid injection into the nerve (stop if electric shock sensation).
• Short course oral prednisolone 20 mg daily for 1 to 2 weeks has been used, but local injection is preferred, and oral steroids carry glucose and blood pressure effects.

Surgery

• Carpal tunnel release under local anaesthesia is reserved for: severe disease with motor weakness, thenar wasting, constant numbness, or intractable pain not controlled by splinting and injection. Otherwise defer surgery until after delivery.

Postpartum

• Expect resolution within 3 months in most women; review at 6 to 12 weeks postpartum.
• Refer for nerve conduction studies and surgery if symptoms persist for over 3 to 6 months after delivery or are severe, or if weakness develops.
• Breastfeeding: paracetamol and local injection are compatible; avoid repeated oral steroid courses.

Follow up

• Review each antenatal visit; check blood pressure and urine; escalate for sudden bilateral swelling.