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

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 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:
• Chronic obstructive pulmonary disorder (COPD)
• Severe asthma
• Severe ischemic heart disease
• Left-sided heart failure
• Chronic laryngitis, chronic bronchitis, emphysema, pneumonia
• Latent or active tuberculosis
• Chronic cough
• Neurological problems (e.g. seizure disorder)
• Severe scoliosis with no history of surgical correction or management.
• Organ transplant
• HIV or other immunocompromising conditions
• Autoimmune disease with possible vascular complications (e.g. Lupus)
• Significant respiratory compromise (e.g., severe dyspnea, O₂ saturation <95%, uncontrolled asthma, history of pneumothorax)