A 28-year-old woman with a 3-year history of generalized tonic-clonic seizures presents to the neurology clinic. She has been seizure-free for 6 months on levetiracetam 1000 mg twice daily. MRI brain and EEG are normal. She is planning pregnancy within the next 6 months and asks about her antiepileptic drug (AED). What is the most appropriate next step in management?