Reproductive Outcome Registration in Phase 3 Weight‐Management Pharmacotherapy Trials: A Cross‐Sectional Meta‐Research Study

ABSTRACT Aims To quantify registered reproductive outcome measures in women and men in adult Phase 3 weight‐management pharmacotherapy trials and compare them with registered body‐composition measures. Materials and Methods Cross‐sectional meta‐research study of ClinicalTrials.gov records as registered on 31 August 2026. Eligible trials were randomised, controlled, Phase 3 or 2/3, with registered minimum age ≥ 18 years, a pharmacological intervention, weight or BMI as a registered primary outcome and a weight‐related registered condition. Registered outcome fields were classified with a published dictionary. Analyses used exact Clopper–Pearson intervals and paired counts; programme‐level, mechanism and age‐relaxed analyses were post hoc. Results Of 230 trials (91 development programmes; 3711 registered outcome measures), two registered any reproductive outcome measure (0.87%, 95% CI: 0.11–3.11), both in polycystic ovary syndrome populations with non‐industry sponsors; none of 227 trials without a reproductive indication did. No trial enrolling men registered a named male gonadal‐endocrine or semen measure (0/228, 95% CI: 0.00–1.60). Among trials of glucagon‐like peptide‐1‐based agents it was 2/152 (1.32%). Body composition was registered in 33 trials, 31 without any reproductive measure and none the reverse; at programme level, 22 versus none. Admitting trials with minimum age below 18 years gave 7/254 (2.76%), including two industry trials registering gonadal hormones in adolescent safety panels. Conclusions Qualifying reproductive outcomes were rarely registered in adult Phase 3 weight‐management pharmacotherapy trials on ClinicalTrials.gov , including 31 of 33 trials registering body composition. This identifies a gap in publicly registered evidence, not absence of measurement; registering reproductive assessments where undertaken would improve their discoverability.