Statistical analysis
All analyses will be performed using the most recent version of STATA. Baseline data will presented as mean with SD for normally distributed data, and median with interquartile ranges for nonnormally distributed data. Data on tobacco use and alcohol use will be presented as percentage of users. The analyses will be blinded with regard to the treatment regimen for the researcher performing the data analyses. Estradiol use will be coded as 0 (normal dosage) or 1 (double dosage), and progesterone will be coded as 0 (no use), 1 (200 mg), or 2 (400 mg). Thereafter, linear mixed model analyses with measurements clustered within participants will be performed, with breast volume as continuous outcome variable and time with set time points at 0, 3, 6, and 12 months as determinants [We considered an average increase of 30% of breast volume – corresponding to one bra cup size increase – as a clinically relevant outcome after one year of study treatment. From previous studies, it is known that the ratio of two consecutive breast volume measurements is 1.08 with a standard deviation of 0.27 [