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)
