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Regenerative Medicine

Combined hormonal contraceptives remodels architecture and mitochondrial proteins in skeletal muscle

1703 - Combined hormonal contraceptives remodels architecture and mitochondrial proteins in skeletal muscle

Thursday, February 19, 2026

5:00 PM - 6:30 PM AST

Presenting Author(s)

AH

Arielle Hall, DO

Resident Physician
University of Pittsburgh Medical Center
Pittsburgh, Pennsylvania, United States

Co-Author(s)

AB

Abraham Brown, BS

Medical Student
Lake Erie College of Osteopathic Medicine
Pittsburgh, Pennsylvania, United States
JK

Jagruti Kosaraju, MS

Research Technician
University of Pittsburgh
Pittsburgh, Pennsylvania, United States
NV

Nithila Vijayan, n/a

Research Intern
South Fayette High School
Pittsburgh, Pennsylvania, United States
ZC

Zachary Clemens, PhD

Post-Doctoral Fellow
University of Pittsburgh
Pittsburgh, Pennsylvania, United States
EC

Ellen Casey, MD

Physician
Hospital for Special Surgery
NY, New York, United States

Corresponding Author(s)

AS

Amrita Sahu, PhD

Assistant Professor
University of Pittsburgh
Pittsburgh, Pennsylvania, United States

Submitter(s)

AH

Arielle Hall, DO

Resident Physician
University of Pittsburgh Medical Center
Pittsburgh, Pennsylvania, United States

Objectives: Women are more prone to musculoskeletal injuries, yet female-focused research is lacking. This pilot study explores the effect of combined hormonal contraceptives (CHCs) on skeletal muscle health, aiming to understand their role in enhancing strength, resilience, and injury recovery.

Design: Twelve-week-old female C57BL/6J mice were divided into three groups and orally administered exogenous sex hormones (Group 1: Control, Group 2: 2 mg/kg ethinyl estradiol and 200 mg/kg levonorgestrel [L-EE/LNG], Group 3: 5 mg/kg ethinyl estradiol and 200 mg/kg desogestrel [H-EE/DSG] for six weeks. Estrus cycling was confirmed with daily vaginal cytology. Tibialis anterior (TA) muscles were collected and frozen for histological analysis of myofiber size, collagen-2, lipid, and mitochondrial health (SDHA).

Results: There was a significantly higher percentage of large muscle fibers ( >2,500µm²) in the H-EE/DSG group compared to both the control and L-EE/LNG groups (p < 0.05), suggesting hormone dosage impacts fiber size distribution. Lipids remained unchanged across groups (p >0.05). While there was no difference between L-EE/LNG and control for SDHA expression levels, a 25% increase in SDHA with H-EE/DSG group compared to controls was found. Likewise, there was no difference between L-EE/LNG and control for collagen II expression, however, we found a 16.8% increase in collagen II with H-EE/DSG group compared to controls.

Conclusions: Higher estrogen levels in combined hormonal contraceptives (CHCs) may increase myofiber size, collagen II expression, and mitochondrial health in skeletal muscle, potentially enhancing force production, strength, and endurance. These findings suggest estrogen dose plays a potential role in muscle adaptation. Future research will expand sample sizes and include groups with varied progesterone types and levels to assess their specific effects. The ultimate goal is to understand how different hormone combinations in CHCs influence muscle health, aiding the development of hormone-informed regenerative rehabilitation strategies for women, particularly athletes at higher risk for musculoskeletal injuries.