Winkles JF, Colvin A, El Khoudary SR, Santoro N, Sammel M, Crawford S. Using a Composite Summary of Daily Sex Hormones to Gauge Time Until Menopause: A Focus on Pregnanediol Glucuronide (PDG). J Clin Endocrinol Metab. 2025 Sep 16; 110(10):2832-2844.