Review Question - QID 216404

A 33-year-old woman presents to the emergency department with an episode of contractions of her extremities, tongue biting, and subsequent confusion. She is diffusely tremulous and nauseous on arrival. She has a history of alcohol use disorder and drinks 1 to 2 liters of hard alcohol daily with her last drink over a day ago. She currently takes oral contraceptive pills. She states she is also supposed to be taking a seizure medication but has not for some time. Her temperature is 98.5°F (36.9°C), blood pressure is 143/81 mmHg, pulse is 80/min, respirations are 20/min, and oxygen saturation is 97% on room air. Physical exam reveals an uncomfortable, diaphoretic woman. She is given a phenobarbital loading dose and is admitted to the hospital. She is ultimately discharged on phenobarbital to manage her seizure disorder. She returns to her primary care physician 2 months later with a positive home pregnancy test. She is concerned as she has been taking her medications as prescribed including her oral contraceptive pills. Which of the following is the most likely explanation for her positive pregnancy test?