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.
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
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
Parallel
Exercise at 15% PI max
Other interventionMinimal resistance training, similar to yoga, for 5 to 8 minutes a day over six weeks.
Exercise at 50% PI max
Other interventionModerate resistance training, similar to strength training for 5 to 8 minutes a day over six weeks.
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.
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.
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.
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.
Change from Baseline in Perceived Sleep Quality
Change in self-reported sleep quality as measured by the PROMIS Sleep Disturbance short form, administered weekly via MyCap.
Change from Baseline in Dyspnea Severity
Change in self-reported shortness of breath severity as measured by the PROMIS Dyspnea Severity items, administered weekly via MyCap.
Change from Baseline in Perceived Stress
Change in perceived stress as measured by the Perceived Stress Scale (PSS), administered weekly via MyCap.
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University of Arizona
Lead sponsor
Banner University Medical Center
Collaborator
