Fig. 1. Mean concentrations of estradiol and ionized calcium across the menstrual cycle. Data are presented as means (±SE). The PMS group is represented by circles; the asymptomatic group by squares. EF denotes early follicular phase; LL denotes late luteal phase of the menstrual cycle. The asterisk indicates p<0.05 for the change from EF to Day 0 or from Day 0 to LL.