RecruitingEarly Phase 1

Breathing for Two: Inspiratory Muscle Strength Training for Supporting Healthy Blood Pressure in Pregnancy

United States80 participantsStarted 2026-06-08

Plain-language summary

This is an interventional study that will test whether a breathing exercise called Inspiratory Muscle Strength Training (IMST) can safely and effectively lower blood pressure during late pregnancy. The goal is to see if a home-based breathing training can help prevent or reduce high blood pressure disorders in pregnancy. The main objectives are to make sure the training is safe and tolerable for pregnant women and to examine blood pressure and blood vessel health. Participants in their third trimester will be randomly assigned to either do moderate resistance IMST or a minimal resistance sham IMST, for 5 to 8 minutes a day over six weeks.

Who can participate

Age range

18 Years – 55 Years

Sex

FEMALE

See this in plain English?

AI-rewrites the medical criteria so a patient or caregiver can understand them. Always confirm with the trial site.

Inclusion Criteria: * Female sex * Pregnant (32 to 34 weeks of gestation, confirmed by ultrasound, at the time of first training session, eligible patients may consent/enrolled earlier in pregnancy) * Singleton pregnancy * Age 18 to 55 * Able to read English and provide consent * Possess smartphone for syncing the AiroFit and Omron devices using Bluetooth and completing online surveys * Smartphone updated to iOS 12+ or Android 11+ * No contraindication for moderate exercise at time of enrollment * Not planning delivery for at least one month at time of enrollment (\< 38 weeks of gestation) * Willing to adhere to AiroFit device use throughout study period * Must already be scheduled, or in the process of scheduling, for weekly NST appointments by 32 to 34 weeks gestational age (per provider order / due to obstetric indication) Lower-Risk Pregnancy Cohort Inclusion Criteria: * No history or evidence of hypertensive disorders of pregnancy * May be undergoing antenatal testing for: * Conception via in vitro fertilization, BMI ≥ 35, an advanced maternal age (age \>/=35), or other condition not listed in exclusion criteria or 'higher risk for HDP group' but is recommended for antenatal testing. Higher-Risk Pregnancy Cohort Inclusion Criteria: * Conditions associated with higher risk of developing HDP, including: * Gestational diabetes mellitus, chronic hypertension, gestational hypertension, or a history of preeclampsia in a previous pregnancy Exclusion Criteria: * Younger t…

Questions worth asking your doctor

Bring these to your next appointment. They're a starting point for a shared conversation — not a sign you qualify or a recommendation to enrol.

1Since this is an Early Phase 1 trial specifically focused on whether inspiratory muscle strength training is safe during pregnancy, what do we currently know about the risks of this kind of breathing exercise for someone in my situation, and what would you want to watch for if I were to participate?
2The trial is measuring safety events for both me and my baby — can you help me understand what types of complications or warning signs the researchers are specifically watching for, and how quickly I would be pulled from the study if something concerning came up?
3The study tracks blood pressure changes and also something called endothelial function through a test called Post-Occlusive Reactive Hyperemia — can you explain what that test involves and whether the demands of regular blood pressure monitoring at home and these measurements would realistically fit into my pregnancy care schedule?
4Because this is an early-phase trial, the main goal is safety and feasibility rather than proving the treatment works — given that, would you recommend I consider this trial before, after, or instead of other approaches you might use to manage blood pressure during my pregnancy?
5The trial involves a daily breathing exercise program done at home — are there any aspects of my specific pregnancy or health history that would make you especially cautious about me doing high-resistance inspiratory muscle training on a regular basis?

Generated to help you prepare — always confirm anything about your own eligibility and care with the study team and your doctor.

Questions for the trial coordinator

The trial coordinator is the person who runs the study day to day. These cover the practical side — logistics, costs, and what taking part would actually mean for your life. The study team confirms whether you meet the criteria; these are questions to ask, not a sign you qualify.

1What does taking part actually involve week to week — how many visits, where, and how long does each one take?
2What costs are covered by the study, and what might I have to pay for myself, including travel, parking, or time off work?
3What happens during screening, and what happens if the study team confirms I don't meet the criteria after those tests?
4Who pays for the scans, blood work, and other tests the trial requires — the study, my insurance, or me?
5How will being in the trial affect my regular care, and will my own doctor stay informed and involved?
6Can I leave the trial at any point if I change my mind, and what would happen to my care if I do?

A starting point for the conversation — always confirm anything about your own eligibility, costs, and care with the study team and your doctor.

What they're measuring

Incidence of Maternal and Fetal Safety Events During Inspiratory Muscle Strength Training (IMST)

Timeframe: 6 weeks

Adherence to IMST Training and Home Blood Pressure (BP) Monitoring

Timeframe: 6 weeks

Change from Baseline in Systolic Blood Pressure

Timeframe: 6 weeks

Change from Baseline in Endothelial Function as Assessed by Post-Occlusive Reactive Hyperemia (PORH)

Timeframe: 6 weeks

Change from Baseline in Urinary Nitrite/Nitrate Concentration

Timeframe: Change in urinary nitrite/nitrate concentration (µM), measured weekly via Griess colorimetric assay (Cayman Nitrite Colorimetric Assay), as an indirect marker of nitric oxide bioavailability.

Trial details

NCT IDNCT07687745

SponsorUniversity of Arizona

Sponsor typeOTHER

Study typeINTERVENTIONAL

Primary completion2027-06-30

Contact for this trial

Elise Erickson, PhD

520-621-1139 eliseerickson@arizona.edu

View on ClinicalTrials.gov More Hypertension Disorders in Pregnancy trials

Plain-language summary

Who can participate

Age range

18 Years – 55 Years

Sex

FEMALE

See this in plain English?

AI-rewrites the medical criteria so a patient or caregiver can understand them. Always confirm with the trial site.

What they're measuring

Incidence of Maternal and Fetal Safety Events During Inspiratory Muscle Strength Training (IMST)

Timeframe: 6 weeks

Adherence to IMST Training and Home Blood Pressure (BP) Monitoring

Timeframe: 6 weeks

Change from Baseline in Systolic Blood Pressure

Timeframe: 6 weeks

Change from Baseline in Endothelial Function as Assessed by Post-Occlusive Reactive Hyperemia (PORH)

Timeframe: 6 weeks

Change from Baseline in Urinary Nitrite/Nitrate Concentration