Fig. 1: Crossover experimental design examining the effects of estradiol and progesterone administration in the perimenstrual (natural E2 and P4 withdrawal) phase of the cycle.

In the “Experimental Design” panel, we outline (1) how at-home LH testing was used to schedule the experimental interval (study medication, laboratory visits), and (2) how cycle phases were coded during the experimental interval using both LH testing and self-reported menses onset. In the “Placebo Condition” and “Active Condition” panels, we describe the timing and other details of medication administration, along with hypothesized hormone levels in the two conditions.