Energy Deficiency on Hormones in Contraceptive Users

Effects of a Modest Energy Deficit on Reproductive Hormones Across the Menstrual Cycle in Contraceptive Users

The purpose of the present study is to characterize the endocrine and metabolic responses to a modest, short-term energy deficiency (~250 kcal/day) across the menstrual cycle in recreationally active women using different contraceptive methods (oral contraceptive, hormonal IUD, and non-hormonal IUD). This study will leverage daily urinary hormone metabolite tracking and comprehensive metabolic assessments, providing foundational data addressing an important and previously unexamined interaction between energy availability and hormonal regulation in contraceptive users.

Study Overview

• Status: Not yet recruiting
• Conditions: Energy Deficiency Due to Short-term Fasting; Hormonal Contraception
• Intervention / Treatment: Behavioral: Energy Deficiency of approximately ~250 kcal/day

Detailed Description

The purpose of the present study is to characterize the endocrine and metabolic responses to a modest, short-term energy deficiency (~250 kcal/day) across the menstrual cycle in recreationally active women using different contraceptive methods. The investigators will be focusing on oral contraceptive users, hormonal IUD, and non-hormonal (i.e., copper IUD). Daily urinary hormone metabolite tracking and comprehensive metabolic assessments (i.e., resting metabolic rate, body composition via DXA, exercise logs, and energy intake) will be used to provide foundational data addressing an important and previously unexamined interaction between energy availability and hormonal regulation in contraceptive users.

Based on evidence that female reproductive hormones are sensitive to energetic stress, that estrogen plays a central role in regulating metabolism and endocrine function, and that hormonal contraceptive methods differentially alter endogenous hormone profiles, the central hypothesis of this study is that a modest, controlled energy deficiency (~250 kcal/day) will alter reproductive hormone profiles across the menstrual cycle in recreationally active women using contraceptives. Specifically, it is hypothesized that changes in urinary reproductive hormone measures will be detectable during an energy-deficient cycle compared to a baseline cycle, and that the magnitude and pattern of these changes will differ by contraceptive type, with hormonal oral contraceptive users demonstrating a different hormonal response to energy deficiency than copper or hormonal intrauterine device users.

A secondary hypothesis is that energy deficiency-induced hormonal changes will be associated with alterations in resting metabolic rate and body composition, and that these associations may be moderated by exercise energy expenditure and perceived stress. Collectively, these hypotheses are grounded in prior research demonstrating hormonal sensitivity to energetic perturbations and the distinct endocrine environments created by different contraceptive methods, while addressing a clear gap in the current literature regarding the interaction between energy availability and hormonal regulation in contraceptive users.

• Study Type: Interventional
• Enrollment (Estimated): 30
• Phase: Not Applicable

Contacts and Locations

• Study Contact: Name: Emily Lundstrom, PhD; Phone Number: 3234422180; Email: elundstr@usc.edu

Study Locations

• United States
  • California
    • Los Angeles, California, United States, 90033
      • University of Southern California Health Sciences Campus Center for Health Professions
      • Contact: Emily Lundstrom, PhD; Phone Number: 3234422180; Email: elundstr@usc.edu

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

• Female, aged 18-35 years
• Recreationally active (engaging in structured exercise between 8-15 hours per week)
• BMI of 18.5-29.9 as a BMI below or above these cut points results in highly varied menstrual cycle lengths17
• Not currently experiencing an eating disorder or disordered eating, or having a diagnosed eating disorder in the last 3 years
• Non-pregnant or planning to become pregnant
• Medically free from chronic diseases
• Currently using one of the following contraceptive methods for ≥3 months:

Monophasic oral contraceptive

• Hormonal intrauterine device (H-IUD)
• Copper intrauterine device
• Weight stable (no weight change >5% body weight within the past 3 months)
• Weight greater than or equal to 110 lbs
• Not suffering from known gynecological disease (i.e., PCOS, endometriosis, etc.) that may influence menstrual cycle regularity
• Willing and able to maintain current exercise habits throughout the study
• Willing to follow study dietary guidance to achieve a ~250 kcal/day energy deficit during Cycle 2

Exclusion Criteria:

• Amenorrhea or oligomenorrhea
• Perimenopausal or menopausal
• Currently pregnant, planning pregnancy, or breastfeeding
• Use of hormonal contraception other than monophasic oral contraceptives or hormonal IUD (implant, nuvaring, etc.)
• Initiation or change of contraceptive method within the past 3 months
• Diagnosis of polycystic ovary syndrome (PCOS), endometriosis, hypothalamic amenorrhea, or other known reproductive endocrine disorder
• Current or history of eating disorder or clinically diagnosed disordered eating
• Current participation in intentional weight loss or weight gain program
• Use of medications known to affect metabolism or hormone levels (e.g., systemic corticosteroids, thyroid medications, insulin, GLP-1 agonists)
• Known metabolic, cardiovascular, renal, hepatic, or endocrine disease
• Musculoskeletal injury limiting exercise participation within the past 3 months
• Smoking or nicotine use
• Contraindications to DXA scanning (e.g., pregnancy, recent high-radiation diagnostic imaging exceeding institutional limits)
• Inability or unwillingness to comply with study procedures

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Screening
• Allocation: Non-Randomized
• Interventional Model: Parallel Assignment
• Masking: None (Open Label)

Number of Arms

3

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Monophasic low dose oral contraceptive users; The first group will be only individuals who are on a low dose, monophasic oral contraceptive that they have elected to be on prior to enrollment in the study. They will undergo a baseline monitoring menstrual cycle that will include daily urinary hormone monitoring, baseline metabolic and body composition assessments, and assessment of baseline energy expenditure and energy intake. During a two week washout week, participants will not be monitoring hormones, but will be subjected to a ~250 kcal/day energy deficit. Following this imposed energy deficiency, they will resume urinary metabolite testing and exercise intake and expenditure tracking. They will undergo this monitoring for a final menstrual cycle and metabolic and body composition assessments, and assessment of energy expenditure and energy intake.	Behavioral: Energy Deficiency of approximately ~250 kcal/day; Following an initial baseline menstrual cycle, participants will be subjected to at least two weeks of a ~250 kcal/day energy deficit monitored through daily diet tracking.
Experimental: Hormonal IUD; The second group will be only individuals who have a hormonal IUD that they have elected to be on prior to enrollment in the study. They will undergo a baseline monitoring menstrual cycle that will include daily urinary hormone monitoring, baseline metabolic and body composition assessments, and assessment of baseline energy expenditure and energy intake. During a two week washout week, participants will not be monitoring hormones, but will be subjected to a ~250 kcal/day energy deficit. Following this imposed energy deficiency, they will resume urinary metabolite testing and exercise intake and expenditure tracking. They will undergo this monitoring for a final menstrual cycle and metabolic and body composition assessments, and assessment of energy expenditure and energy intake.	Behavioral: Energy Deficiency of approximately ~250 kcal/day; Following an initial baseline menstrual cycle, participants will be subjected to at least two weeks of a ~250 kcal/day energy deficit monitored through daily diet tracking.
Experimental: Non-Hormonal (i.e., Copper) IUD; The last group will be only individuals who have a non-hormonal/copper IUD that they have elected to be on prior to enrollment in the study. They will undergo a baseline monitoring menstrual cycle that will include daily urinary hormone monitoring, baseline metabolic and body composition assessments, and assessment of baseline energy expenditure and energy intake. During a two week washout week, participants will not be monitoring hormones, but will be subjected to a ~250 kcal/day energy deficit. Following this imposed energy deficiency, they will resume urinary metabolite testing and exercise intake and expenditure tracking. They will undergo this monitoring for a final menstrual cycle and metabolic and body composition assessments, and assessment of energy expenditure and energy intake	Behavioral: Energy Deficiency of approximately ~250 kcal/day; Following an initial baseline menstrual cycle, participants will be subjected to at least two weeks of a ~250 kcal/day energy deficit monitored through daily diet tracking.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Urinary hormone exposure	Participants will be asked to track daily urine concentrations of estrogen and progesterone throughout a baseline (i.e., non-energy-deficient state) menstrual cycle and a menstrual cycle with an imposed energy deficit. The outcome will compare hormone exposure measured by the urinary concentrations between the two cycles.	From enrollment to energy deficit menstrual cycle is 3 months/90 days

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Estimated versus actual resting metabolic rate	Body composition and estimated metabolic rate will be collected using DXA. The DXA will be measured at baseline and at the conclusion of the energy-deficient menstrual cycle. Resting metabolic rate will be measured via indirect calorimetry testing at baseline, at the beginning of the second monitored (i.e., energy-deficient) menstrual cycle, and at the conclusion of the energy-deficient menstrual cycle. The estimated and actual metabolic rate will be compared as an assessment of energy status. Participants will also be asked to track exercise using a paper log or wearable device to estimate exercise energy expenditure (EEE), and daily intake (EI) will be measured via a paper log or an application. These values will be subtracted (EI-EEE) and normalized to fat-free mass collected via DXA to estimate energy availability.	From enrollment to completion 90 days/3 months
Eating behaviors and attitudes will be measured using the EDEQ and the Three Factor Eating Questionnaire	The Eating Disorder Examination Questionnaire is a 12 item questionnaire scaled from 0 to 3 (0 being 0 days and 3 being 6 to 7 days) assessing feelings around eating behaviors, body image, and restraint. The Three Factor Eating questionnaire is an 18-question survey that assesses cognitive restraint, emotional eating, and uncontrolled eating on a 4 point Likert scale (0 being never and 3 being at least once a week).	From enrollment to conclusion 90 days/3 months
Subjective stress levels will measured using the Perceived Stress Scale	The Subjective Stress Scale measures percieved stress through 10 questions about recent stress perceptions on a 0 to 4 Likert scale (0 being never; and 4 being very often).	From enrollment to conclusion 90 days/3 months
Low Energy Availability Indicators will be assessed using the LEAF-Q	The low energy availability in Females Questionnaire (LEAF-Q) is used to identify female athletes 'at risk' of low energy availability. This questionnaire assesses physiological symptoms associated with LEA, including 25 questions arranged into 3 sections; eating and reproductive assessment, injury assessment, and gastrointestinal symptom assessment. A total score of ≥8 out of 25 questions indicates that the athlete is at risk of LEA. There is a standardized scoring system that varies by question and subquestion.	From enrollment to conclusion 90 days/3 months
Body composition will be measured using DXA	Dual-energy x-ray absorbtometry will be used to assess body composition including segmental analysis of body fat and lean mass.	From enrollment to conclusion 90 days/3 months

Collaborators and Investigators

• Sponsor: University of Southern California

Study record dates

Study Major Dates

• Study Start (Estimated): September 1, 2026
• Primary Completion (Estimated): June 1, 2027
• Study Completion (Estimated): December 1, 2027

Study Registration Dates

• First Submitted: April 23, 2026
• First Submitted That Met QC Criteria: June 10, 2026
• First Posted (Actual): June 16, 2026

Study Record Updates

• Last Update Posted (Actual): June 16, 2026
• Last Update Submitted That Met QC Criteria: June 10, 2026
• Last Verified: June 1, 2026

More Information

Terms related to this study

• Other Study ID Numbers: HS-26-00204

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No