Long-acting Reversible Contraceptives, Iron, and Extreme Environments in Women
This observational study is looking at how long-acting reversible contraceptives (LARCs), like implants or intrauterine devices (IUDs), might affect your body's iron levels and how you respond to extreme environments such as heat, cold, and high altitudes. Researchers want to understand if these contraceptives, which are safe and effective for preventing pregnancy, have an impact on your physical responses in these challenging conditions. They will be measuring your iron status and how your body reacts to these environments. This study is for women aged 18 to 40 who have been using monophasic oral contraceptives or implantable contraception for at least one year. The study plans to enroll 33 participants, but its current status is unclear.
- Study design
- This is an observational study planning to enroll 33 women. It will look at how long-acting reversible contraceptives affect iron levels and responses to extreme environments.
- What's involved
- You would undergo testing of your blood volume, iron stores, and your body's responses to heat, cold, and high-altitude exposures. Core temperature will be measured intermittently during heat exposure, and ventilation during high-altitude trials.
- Compensation
- Not stated in the trial record.
- Follow-up
- Iron status is measured at the initial visit. Ventilation is measured intermittently throughout the high-altitude trial (5 times over 6-7 hours), and core temperature intermittently during heat exposure for 2 hours.
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NCT06909695
Influences of Long-acting Reversible Contraceptives on Iron Status and Physiological Responses to Extreme Environments in Women
Recruiting
Not specifiedAges 18–40ObservationalUnited States Army Research Institute of Environmental MedicineGovernment-funded
~33 participants
Updated 2026-04-30 on ClinicalTrials.gov
What's tested:Blood volume and environmental testing
At a glance
Recruiting sites
1 of 1 listed site is recruiting right now
RecruitingSuspended, closed, or not yet open
What they're measuring
Iron status
Measured over upon initial visit
+7 more outcomes measured
Conditions
Where it's being run
1 sites across 1 statesMassachusetts1
Study leadership
- Gabrielle Giersch, PhD · PRINCIPAL_INVESTIGATOR · United States Army Research Institute of Environmental Medicine
Who to contact
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Do you actually qualify for this trial?
Add a private profile and we'll compare every criterion below against your situation — and tell you which ones are met, uncertain, or excluding.
Eligibility criteria
Inclusion
• Females, age 18-40 y
Females taking monophasic oral contraceptives or utilizing implantable contraception (intrauterine device, implantable bar) for at least one year, and be at least one year removed from the removal end point (e.g. before year 4 for a 5-year IUD)
In good health as determined by OMSO (Office of Medical Support and Oversight)
Passed most recent Army Combat Fitness Test (ACFT) (military volunteers only) or exercise at least 2 times per week (civilian volunteers)
Willing to not drink alcoholic beverages for 24 hours before each testing session
Willing to not consume caffeine 12 hours prior to any testing sessions
Willing to refrain from any exercise and additional moderate to strenuous physical activity 24 hours prior to testing
Willing to stay and exercise in an altitude chamber (the size of a dorm room) for \~6 hours
Supervisor approval for federal civilian employees and non-HRV active-duty military personnel stationed at NSSC.
Exclusion
• Females who are pregnant, planning to become pregnant during the study, or breastfeeding.
Taking prescription, over the counter medication, or dietary supplements, other than a contraceptive (unless approved by OMSO and Principal Investigator (PI))
Tobacco or nicotine users, or anyone who has used tobacco or nicotine within the last four months
Physical problems/injuries (e.g., current stress fractures, musculoskeletal strains) that would affect walking or running on a treadmill
Allergy to skin adhesive
Heart, lung, kidney, muscle, endocrine, or nerve disorder(s) as determined by OMSO
History of heat intolerance or orthostatic intolerance
Diagnosed and/or treated for fluid/electrolyte imbalance within the last 30 days
History of obstructive disease of the gastrointestinal tract including (but not limited to) diverticulosis, diverticulitis and inflammatory bowel disease, peptic ulcer disease, Crohn's disease, ulcerative colitis.
Scheduled MRI within 2 weeks after completing a heat or cold test
Actively dieting with the intent to lose weight
History of cold injuries of any severity (e.g., frostbite, trench foot, chilblains).
Raynaud's syndrome
Cold-induced asthma/bronchospasm
Not willing to have small areas of skin on the body shaved (if deemed necessary for attachment of study instrumentation)
Born at altitudes greater than 2,100 m (7,000 ft) (e.g., Mexico City, Mexico)
Living in areas that are more than 1,200 m (4,000 ft) (e.g., Colorado Springs, CO) or have traveled to areas that are more than 1,200 m for five days or more within the last 2 months
Prior diagnosis of High Altitude Pulmonary Edema (HAPE) or High Altitude Cerebral Edema (HACE)
Abnormal blood count in accordance with OMSO - Normal Hb women: 11.1-15.9 g·dL-1 or Normal Hct women: 34.0-48%, or presence of abnormal blood chemicals (hemoglobin S or Sickle Cell Trait)
History of pneumothorax
History of hypertension
Blood donation within 8 weeks of beginning the study
Any recent (within 4-6 weeks) and or expected history of prolonged periods of immobility or limited activity (including recent or upcoming surgery)
Evidence of apnea or sleeping disorder (narcolepsy, insomnia, etc.)
What this trial measures
- Iron statusupon initial visit
Iron stores as measured by ferritin levels
- Ventilationintermittently throughout high-altitude trial (5 timepoints overall over ~6-7 hours)
ventilatory response to high altitude exposure at rest and during exercise
- Thermoregulation in the heat - core temperaturemeasured intermittently throughout trial (at least every 5 minutes) for 2 hour exposure
Measure of core temperature
- Thermoregulation in the cold - skin blood flowmeasured intermittently throughout cold trial (at least every 5 minutes) for 2 hour exposure
Measure of thermoregulation during resting cold stress to include skin blood flow
- Thermoregulation in the heat - skin temperaturemeasured intermittently throughout trial (at least every 5 minutes) for 2 hour exposure
- Thermoregulation in the heat - sweating rateOnly measured during heat stress visit, at one timepoint immediately after exercise on heat stress visit (post-exercise, within 10-20 minutes)
Calculated from pre- and post-nude body mass corrected for fluid consumed and urine produced
- Thermoregulation in the cold - core temperaturemeasured intermittently throughout cold trial (approximately every 5-10 min) for 2 hour exposure
- Thermoregulation in the cold - skin blood flowmeasured intermittently throughout cold trial (approximately every 5-10 minutes) for 2 hour exposure