Fig. 8

Secondary outcomes: Method of determining menstrual phase. A Progesterone concentrations (log10 ng/mL) and days since last menstrual period. Each symbol is a single sample. Samples are categorized into follicular (blue) or luteal (green) phases based on days since LMP (top) or serum progesterone (bottom). The same samples are shown in both plots. Gray symbols have undefined phase. B The number of samples categorized as follicular phase, luteal phase, or undefined by serum progesterone and by days since LMP. Squares are colored based on whether the methods categorized those samples as the same phase (green), opposite phases (orange), or one method was undefined (gray)