Analysis of pregnanediol glucuronide (PDG) and progesterone (P4) in daily uring samples in the confirmatory cohort (ovulation identified by ultrasound). Solid line – median. Dashed line – 10th centile. Dotted line – 90th centile. Ov: day of ovulation. Day represents cycle day relative to day of ovulation. PDG: pregnanediol-3-glucuronide, P4: Progesterone, Architect: Abbott Architect chemiluminescent microparticle immunoassay. Cobas: Roche Cobas e411 electrochemiluminescence immunoassay.