A pregnant 30-year-old woman complains of persistent numbness on the palmar surface of her right hand and of pain in her right arm. Her symptoms are more severe in the morning. Neurologic examination reveals a sensory deficit in the right thumb and the index and middle fingers, as well as on the lateral half of the ring finger. The patient has weakness when abducting the thumb. Which of the following is considered first-line treatment?

Choice A reason: Gabapentin is used for neuropathic pain but is generally not first-line for mild to moderate carpal tunnel syndrome, especially during pregnancy. Choice B reason: Anti-inflammatory medications may be limited during pregnancy due to safety concerns and are not the most effective treatment for compressive neuropathy in the wrist. Choice C reason: Corticosteroids can provide relief but systemic steroids are generally avoided in pregnancy unless necessary; localized corticosteroid injections may be used but are second-line. Choice D reason: This choice is correct because wrist splinting, particularly at night, is the first-line conservative treatment for carpal tunnel syndrome, especially in pregnant patients. It helps maintain the wrist in a neutral position, reducing pressure on the median nerve and alleviating symptoms.