Related Experiment Video
Updated: Nov 29, 2025
Establishment of Rat Models Mimicking Gender-affirming Hormone Therapies
Published on: January 10, 2025
Sustained Breast Development and Breast Anthropometric Changes in 3 Years of Gender-Affirming Hormone Treatment
Christel J M de Blok1,2, Benthe A M Dijkman1,2, Chantal M Wiepjes1,2
1Department of Endocrinology, Amsterdam UMC, VU University Medical Center, HV, Amsterdam, the Netherlands.
Context:
Breast development is important for most trans women. An important limitation of current breast development measurement methods is that these do not allow for 3D volume analyses.
Objectives:
To examine breast development and change in anthropometry during the first 3 years of gender-affirming hormone treatment using 3D imaging. Associations with clinical or laboratory parameters and satisfaction with the gained breast development were also studied.
Design:
Prospective cohort study.
Setting:
Specialized tertiary gender identity clinic in Amsterdam, the Netherlands.
Participants:
Participants were 69 adult trans women with a median age of 26 years (interquartile range, 21-38).
Interventions:
Gender-affirming hormone treatment.
Main Outcome Measures:
Volumetric and anthropometric breast development and satisfaction.
Results:
Breast volume increased by 72 cc (95% confidence interval [CI], 48-97) to 100 cc (standard deviation 48). This resulted in a cup-size
Conclusions:
Sustained breast growth and development during hormone treatment was observed during the full 3-year observation period. The breasts of trans women are positioned more laterally and caudally on the chest compared with cis women. Although modest breast volumes were observed, breast development was satisfactory to most trans women.
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