Figure 2.

Difference in estradiol-17β (E₂) concentrations within the first hour after awakening in women with regular menstrual cycles and postmenopausal women. E₂ concentration at each examined time point is depicted in (A). The relative mean increase in E₂ concentration 30 and 60 min after awakening over the individual baseline (E₂-MnInc %) and integrated E₂ concentration ranging from the time immediately upon awakening to 60 min after awakening (i.e. area under the E₂ curve with respect to baseline, E₂auc) are depicted in (B and C) respectively. Each data point in (A) and each bar in (B and C) represents mean±s.e.m. Asterisks denote the level of significance between both groups: **P<0·01; ***P<0·001 (by the Mann–Whitney test).