What is this study trying to find out about female athletes and menstrual cycles?

This study aims to understand how natural menstrual cycles and oral contraceptive use influence strength, hydration, and energy balance in female athletes. Researchers will observe hormone fluctuations and their effects on athletic performance and health. The study is sponsored by Faculdade de Motricidade Humana and hopes to improve knowledge specific to female athletes.

Who may be eligible for this female athlete clinical trial?

Women aged 18 to 30 who are biologically female and have been active in federated sports for at least one year may be eligible. Participants must have had menarche at least three years ago and be either naturally menstruating with regular cycles or using combined oral contraceptives for at least three months. Please review eligibility criteria for more details.

Is there any cost to participate in this female athlete clinical trial?

Study-related care, including all assessments and tests, is provided at no cost. However, personal expenses like travel may vary and are not guaranteed to be covered. Participants should plan accordingly for any travel or accommodation costs.

Actively Recruiting

Age: 18Years - 30Years

FEMALE

Healthy Volunteers

ID07591818

Menstrual Cycle and Oral Contraceptive Use in Athletic Performance and Health-related Hydration and Energy Balance Status

Led by Faculdade de Motricidade Humana · Updated on 2026-05-18

Participants Needed

Research Sites

26 weeks

Total Duration

AI-Summary

What this Trial Is About

Researchers are investigating how natural menstrual cycles and oral contraceptive use affect strength, hydration, energy balance, and body composition in female athletes. This observational study focuses on hormonal changes during specific menstrual phases and oral contraceptive cycles to better understand their impact on athletic performance and health. The study addresses gaps in knowledge about how estrogen and progesterone influence muscle strength, hydration status, and energy availability in female athletes. The study involves 40 female athletes divided into two groups 24 naturally menstruating athletes and 16 oral contraceptive users. Naturally menstruating participants will be assessed during early follicular, late follicular, and mid-luteal menstrual phases, while oral contraceptive users will be evaluated during active pill and withdrawal phases. Testing includes strength measurements using handgrip dynamometry, bench press, and leg press, along with hormonal blood tests, body water and hydration assessments, energy expenditure and balance measurements, and body composition analysis. Participants will attend sessions during each menstrual or contraceptive phase for detailed assessments of strength and hydration. Researchers will monitor hormone levels, body water compartments, hydration markers, energy intake and expenditure, and resting metabolism. The study aims to validate measurement methods and explore relationships between hormone fluctuations and energy availability. Total participation spans multiple menstrual or contraceptive phases, with data collected longitudinally to capture variations over time.

CONDITIONS

Brief Title

Effects of the Menstrual Cycle and Oral Contraceptive Use on Health and Performance in Athletes

Who Can Participate

Age: 18Years - 30Years

FEMALE

Healthy Volunteers

Eligibility Criteria

You may qualify if you...

Cisgender female individuals (biologically female, not undergoing gender-transition therapy)
Age between 18 and 30 years
Classified as at least Tier 2 athletes
Minimum of 1 year of federated sports participation
Menarche occurred at least 3 years prior to enrollment
Menstrual cycle length between 21 and 35 days with at least nine consecutive cycles in the previous year (natural menstrual cycle group only)
Confirmed ovulatory cycle with luteinizing hormone surge and progesterone >16 nmol/L (natural menstrual cycle group only)
Use of combined monophasic oral contraceptives with a 21-day regimen (oral contraceptive group only)
Use of the same oral contraceptive for at least 3 months prior to enrollment (oral contraceptive group only)

You will not qualify if you...

Pregnancy or childbirth within the previous 12 months
Active smoking
Diagnosis of metabolic, cardiovascular, or respiratory disease
Use of continuous or extended-cycle oral contraceptives

Research Team

Flávio Jerónimo

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