Estradiol Concentrations for Adequate Gender-Affirming Feminizing Therapy: A Systematic Review
Bibliographic record
Abstract
Purpose: Guidelines recommend serum estradiol concentrations of 100–200 pg/mL for transgender women prescribed oral, subcutaneous, or transdermal estradiol with or without adjunct antiandrogen as gender-affirming feminizing hormone therapy (HT). The purpose of this systematic review was to evaluate if the guideline range of 100–200 pg/mL for estradiol concentration is associated with indicators of adequate gender-affirming feminizing HT, specifically feminizing sufficiency, insufficiency, testosterone suppression, or toxicity in transgender women. Methods: The Populations/Intervention/Comparator/Outcome model was applied to the study question, whereby the target population included transgender, gender-diverse, and nonbinary adults using gender-affirming feminizing HT by any route of administration, with or without adjunct antiandrogen use. The comparator was defined as estradiol concentrations within (100–200 pg/mL or 367–734 pM) versus outside (</>100–200 pg/mL) the guideline range; evaluated outcomes were listed by the same clinical guidelines that recommend using the 100–200 pg/mL range. Embase, MEDLINE, and Web of Science were queried over a 24-year time frame (January 1, 1999–April 20, 2023); the search was restricted to English. The extracted outcomes were categorized as indicators of therapeutic insufficiency, sufficiency, toxicity, or hormone concentration. Results: There were 49 studies that met the inclusion criteria, of which 9, 42, 25, and 5 studies included indicators of therapeutic insufficiency, sufficiency, toxicity, or hormone concentration, respectively. The search did not identify articles demonstrating that the 100–200 pg/mL guideline range provides optimal feminizing outcomes or reduces adverse events. Conclusions : Evidence does not support using the guideline range of 100–200 pg/mL to indicate sufficient feminization in transgender women using gender-affirming feminizing HT.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.010 | 0.051 |
| Meta-epidemiology (narrow) | 0.001 | 0.001 |
| Meta-epidemiology (broad) | 0.010 | 0.009 |
| Bibliometrics | 0.008 | 0.010 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.003 | 0.003 |
| Open science | 0.002 | 0.001 |
| Research integrity | 0.002 | 0.001 |
| Insufficient payload (model declined to judge) | 0.004 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".