A 29-year-old female with generalized anxiety disorder and a history of major depressive episode has been stable on sertraline 100 mg daily for three years. She is now at 28 weeks gestation and presents with re-emergence of significant anxiety symptoms including persistent worry, insomnia, and somatic tension over the past four weeks. Her GAD-7 score is 16, up from 6 at her first trimester visit. She reports strict medication adherence confirmed by pharmacy refill records. Her prenatal course has been uncomplicated with normal thyroid studies. She denies substance use, major psychosocial stressors beyond normal pregnancy-related concerns, and has a supportive partner. The PMHNP is evaluating the factors contributing to her symptom re-emergence during the third trimester. Which of the following best represents the appropriate evaluation of this clinical scenario?