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

NCT07687745 | Recruiting Early Phase 1 DMC FDA Device

• 1 other identifier: STUDY00007216
• Study Type: interventional
• Target: 80
• Locations: 1 country
• Sites: 1

Brief 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.

Conditions

Hypertension Disorders in Pregnancy; Blood Pressure Measurement in Pregnancy; Pregnancy; Inspiratory Strength Training (IST)

Keywords

pregnancy; blood pressure; hypertensive disorders of pregnancy; imst; hdp; inspiratory muscle strength training

Outcome Measures

Primary Outcomes (5)

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

  Percentage of training sessions associated with abnormal post-training fetal heart rate (FHR) tracing, or with maternal oxygen desaturation (SpO2) or symptoms (e.g., perceived exertion, lightheadedness, hyperventilation), as assessed by study staff during non-stress test (NST) and clinic visits.

  6 weeks

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

  Percentage of prescribed daily IMST training sessions and daily home BP measurements completed by each participant, as captured via training device data and MyCap entries.

  6 weeks

• Change from Baseline in Systolic Blood Pressure

  Change in systolic BP (mmHg), measured via validated automated oscillometric sphygmomanometer (Omron BP7450) per ESH-IP protocol, comparing IMST and sham IMST groups.

  6 weeks

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

  Change in cutaneous microvascular blood flow response (perfusion units) following brief arterial occlusion, measured via Laser Doppler Blood FlowMetry, comparing IMST and sham IMST groups.

  6 weeks

• Change from Baseline in Urinary Nitrite/Nitrate Concentration

  6 weeks

  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.

Secondary Outcomes (3)

• Change from Baseline in Perceived Sleep Quality

  6 weeks

• Change from Baseline in Dyspnea Severity

  6 weeks

• Change from Baseline in Perceived Stress

  6 weeks

Study Arms (2)

Low-Resistance IMST

SHAM COMPARATOR

Other: Exercise at 15% PI max

Moderate-Resistance IMST

ACTIVE COMPARATOR

Other: Exercise at 50% PI max

Interventions

Exercise at 15% PI max OTHER

Minimal resistance training, similar to yoga, for 5 to 8 minutes a day over six weeks.

Low-Resistance IMST

Exercise at 50% PI max OTHER

Moderate resistance training, similar to strength training for 5 to 8 minutes a day over six weeks.

Moderate-Resistance IMST

Eligibility Criteria

• Age: 18 Years - 55 Years
• Healthy Volunteers: Yes
• Age Groups: Adult (18-64)

You may qualify if:

• 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)
• No history or evidence of hypertensive disorders of pregnancy
• May be undergoing antenatal testing for:

You may not qualify if:

• 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
• Younger than 18 or older than 55 years of age
• Multiple gestation (twin or higher-order pregnancy)
• Fetal chromosomal abnormalities or major anatomical anomalies
• Planning to deliver earlier than 38 weeks or within 4 weeks of study enrollment
• Any contraindication for moderate exercise (e.g., cardiomyopathy, congenital cardiac conditions)
• Deep vein thrombosis
• Complications in current pregnancy including intrauterine growth restriction (IUGR), oligohydramnios, preeclampsia, or severe-range blood pressures (\>/=160/110 or \<100/60)
• Active vaginal bleeding, or history of coagulopathy
• Placenta previa or other placental abnormalities (including placental cyst or abruption)
• Signs of labor
• Current substance use disorder
• History of neurological, respiratory, head/neck, or thoracic surgeries, or conditions such as collapsed lung or perforated eardrum
• Individuals with any of the following:

Sponsors & Collaborators

• University of Arizona: lead
• Banner University Medical Center: collaborator

Study Sites (1)

Banner University Medical Center

Tucson, Arizona, 85719, United States

RECRUITING

Related Links

• Related Info

Central Study Contacts

Elise Erickson, PhD

CONTACT

520-621-1139; eliseerickson@arizona.edu

Lily Woods, MA

CONTACT

520-621-1139; lilywoods@arizona.edu

Study Design

• Study Type: interventional
• Phase: early phase 1
• Allocation: RANDOMIZED
• Masking: QUADRUPLE
• Who Masked: PARTICIPANT, CARE PROVIDER, INVESTIGATOR, OUTCOMES ASSESSOR
• Purpose: PREVENTION
• Intervention Model: PARALLEL
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: Associate Professor

Study Record Dates

• First Submitted: June 8, 2026
• First Posted: July 7, 2026
• Study Start: June 8, 2026
• Primary Completion (Estimated): June 30, 2027
• Study Completion (Estimated): September 30, 2027
• Last Updated: July 7, 2026

Record last verified: 2026-07

Data Sharing

• IPD Sharing: Will share
• Shared Documents: STUDY PROTOCOL, SAP, ICF, ANALYTIC CODE
• Time Frame: Upon publication, for a period of 2 years, the IPD will be available using a publicly available repository/storage system (e.g. Open Science Framework or similar).
• Access Criteria: Any data that is made publicly available can be accessed without permission/restriction. Beyond the initial 2 year period, data can be made available upon reasonable request to the PI.

Locations

US (1)