Effect of high altitude on acute mountain sickness in women during their menstrual cycle

HighCycle Study: Effect of High Altitude on Acute Mountain Sickness in Women Related to Their Menstrual Cycle Phase: A Prospective Cohort Study at 3600 m

Observational University of Zurich · NCT06499714

This study looks at how different phases of the menstrual cycle affect the chances of healthy women getting acute mountain sickness when they travel to high altitudes.

Quick facts

Study typeObservational
Enrollment90 (estimated)
Ages18 Years to 44 Years
SexFemale
SponsorUniversity of Zurich Academic / other
Locations1 site (Bishkek, Bishkek)
Trial IDNCT06499714 on ClinicalTrials.gov

What this trial studies

This observational study investigates how the phase of the menstrual cycle affects the incidence of acute mountain sickness (AMS) in healthy women traveling to an altitude of 3600 meters. The study will involve a prospective cohort of women aged 18-44 who are premenopausal and have regular menstrual cycles. Participants will be monitored for symptoms of AMS after exposure to high altitude, allowing researchers to assess the relationship between menstrual cycle phases and AMS incidence.

Who should consider this trial

Good fit: Ideal candidates for this study are healthy, non-smoking women aged 18-44 who live at low altitudes and have regular menstrual cycles.

Not a fit: Patients who are pregnant, nursing, or using hormonal contraceptives other than oral contraceptives may not benefit from this study.

Why it matters

Potential benefit: If successful, this study could provide insights into how menstrual cycle phases influence susceptibility to acute mountain sickness, potentially leading to better prevention strategies for women.

How similar studies have performed: While studies on acute mountain sickness exist, this specific focus on menstrual cycle phases in women at high altitude is relatively novel and has not been extensively tested.

Eligibility criteria

Show full inclusion / exclusion criteria
Inclusion Criteria:

* Healthy, non-smoking women, age 18-44 years, without any disease and need of regular medication (including oral contraceptives).
* BMI \>18 kg/m2 and \<30 kg/m2
* Born, raised and currently living at altitudes \<1000 m
* Written informed consent
* Premenopausal, eumenorrheic cycle

Exclusion Criteria:

* Other types of contraceptives (hormonal intrauterine device, vaginal ring, subcutaneous injections or implants, among others)
* Pregnancy or nursing
* Anaemic (haemoglobin concentration \<10g/dl)
* Any altitude trip \<4 weks before the study
* Allergy to acetazolamide and other sulfonamides

Where this trial is running

Bishkek, Bishkek

Study contacts

How to participate

  1. Review the eligibility criteria above with your treating physician.
  2. Visit the official trial page on ClinicalTrials.gov for the most current contact information and recruitment status.
  3. Contact the listed study coordinator or principal investigator to request pre-screening. Pre-screening is free and never obligates you to enroll.
Conditions Acute Mountain SicknessWomenHypoxiaPreventionAcetazolamideAltitude
Last reviewed 2026-06-13 by the Find a Trial editorial team. Information on this page is for educational purposes and is not medical advice. Always consult qualified healthcare professionals about clinical trial participation.