Figure 3.

Difference in progesterone (P₄) concentration within the first hour after awakening in women with regular menstrual cycles and postmenopausal women. P₄ concentration at each examined time point is depicted in (A). The relative mean increase in P₄ concentration 30 and 60 min after awakening over the individual baseline (P₄-MnInc %) and integrated P₄ concentration ranging from the time immediately upon awakening to 60 min after awakening (i.e. area under the P₄ curve with respect to baseline, P₄auc) are depicted in (A and B) 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).