Two-year prospective, randomized trial comparing an innovative twice-a-week progestin regimen with a continuous combined regimen as postmenopausal hormone therapy  Antonio Cano, M.D., Juan J Tarı́n, Ph.D., José Luis Dueñas, M.D.  Fertility and Sterility  Volume 71, Issue 1, Pages 129-136 (January 1999) DOI: 10.1016/S0015-0282(98)00407-5

FIGURE 1 Percentage of women receiving intermittent or continuous progestin doses each month who recorded spotting (A) or bleeding (B). Open circles and interrupted line = intermittent dosing regimen; closed circles and continuous line = continuous dosing regimen. Fertility and Sterility 1999 71, 129-136DOI: (10.1016/S0015-0282(98)00407-5)

FIGURE 2 Regression lines of the proportion of women (p) with spotting (A) or bleeding (B) at time (x) of treatment with intermittent or continuous progestin doses according to the following model: probit (p) = intercept + B (x). (A), The bottom line, with the sharper slope, corresponds with the intermittent progestin dosing protocol. Pearson goodness-of-fit: P>.05. Parallelism test: P≤.01. Equations for the regression lines: y = 4.51 − 0.064 x (intermittent dosing regimen), and y = 4.35 − 0.030 x (continuous dosing regimen). (B), The bottom line corresponds with the intermittent progestin dosing protocol. Pearson goodness-of-fit: P>.05. Parallelism test: P≤1.00. Equations for the regression lines: y = 3.90 − 0.075 x (intermittent dosing regimen), and y = 3.95 − 0.075 x (continuous dosing regimen). Open circles = intermittent dosing regimen; closed circles = continuous dosing regimen. Fertility and Sterility 1999 71, 129-136DOI: (10.1016/S0015-0282(98)00407-5)

FIGURE 3 Evolution of endometrial thickness (mean ± SEM) for the intermittent and continuous progestin dosing groups during the study, as evaluated by vaginal ultrasound. Open bar = intermittent dosing regimen; striped bar = continuous dosing regimen. Fertility and Sterility 1999 71, 129-136DOI: (10.1016/S0015-0282(98)00407-5)

FIGURE 4 Concentrations of lipids and lipoproteins (means ± SEM) for the intermittent (A) and continuous (B) progestin dosing groups at baseline and at each 6-month visit. At each time point: open bar = cholesterol; striped bar = triglycerides; cross-hatched bar = HDL-C; stippled bar = LDL-C. Fertility and Sterility 1999 71, 129-136DOI: (10.1016/S0015-0282(98)00407-5)