Fig. 4: Time series embedding and probability distribution for period length (all users, across groups).

Time series embedding (a) and probability distributions (b) of period length for the consistently not highly variable (teal) and consistently highly variable (orange) groups. a The period lengths of three consecutive randomly sampled cycles from each user in the cohort are plotted on the x, y, and z axes. Visually, we observe that both groups occupy a very similar region of the period length space (few orange points are placed outside the region occupied by the teal cluster). b The period length probability distributions of the cohort, where we observe that the orange and teal distributions are largely overlapping, with the same median of 4 days and a similar shape, indicating that period lengths are distributed very similarly for the two groups. We notice a slight peak in single day period reports in both groups, which we argue is reminiscent of app usage behavior: some users are interested in knowing (approximately) when they had their period, not in tracking how long it was, so they may only track the day it occurred and not continue tracking after that.