Five minutes a day: breathing training may tame pregnancy blood pressure

Copied word for word from the study's registry entry, so the wording is the study team's rather than ours.

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)