Why Women Are Still Left Out of Clinical Trials—And What It Means for Everyone

New research warns that gender disparities in medical research could persist for decades without systemic reforms.

The Hidden Crisis in Medicine
Imagine a world where half the population gets medications tested primarily on the other half. That’s not dystopian fiction—it’s today’s reality. For over a century, women have been underrepresented in clinical trials, leading to gaps in knowledge about how diseases and treatments affect them differently. From heart disease to COVID-19, this imbalance has left women vulnerable to misdiagnoses, ineffective treatments, and unexpected side effects. A new study led by researchers at the University of Kentucky reveals that without urgent action, this inequity could persist until 2040.

The Study: What We Did
We analyzed female participation in clinical trials for three major infectious diseases—COVID-19, Ebola, and HIV—spanning nearly 30 years (1994–2022). Using advanced statistical modeling, we asked:
How has women’s participation changed over time?
What drives these trends—disease-specific factors or systemic barriers?
What happens if we do nothing?

Our Approach:
Analyzed 15 major trials (3 COVID-19, 5 Ebola, 7 HIV). Used a Bayesian hierarchical model (think of it as a "weather forecast" for clinical trial trends) to separate systemic biases from disease-specific quirks. Projected future participation rates to 2040, including uncertainty ranges.

Key Findings:
Progress? Barely.
COVID-19 trials: 34% female participation in 2020 → 36% in 2022.
Ebola trials: 33% in 2014 → 37% in 2020.
HIV trials: A glacial 6% increase over 30 years (33% in 1994 → 39% in 2020).

A Bleak Forecast:
By 2040, even optimistic projections fall short of equality:
COVID-19: 38% (range: 23–55%)
Ebola: 38% (24–55%)
HIV: 41% (27–57%)

The Real Culprit: Systemic Barriers
Trends across diseases—despite differing contexts—point to structural inequities, such as: Recruitment practices favoring men. Restrictive eligibility criteria excluding pregnant women. Lack of accountability in trial demographics reporting.

Why This Matters
When women are excluded, everyone loses:
Safety Risks: Drugs like Ambien and aspirin were later found to have dangerous side effects in women because early trials underrepresented them.
Efficacy Gaps: Dosages optimized for men may be less effective—or even harmful—for women.
Pandemic Preparedness: Underrepresentation in COVID-19 trials left critical questions about vaccine safety for pregnant women unanswered for months.

Project documentation & code: https:/gBJC2V9K/lnkd.in/