Leg Heating in Pregnant Women With Obesity

Inclusion Criteria: * Women with overweight or obesity (self-reported pre-pregnancy body mass index ≥25 kg/m2) between 10-14 weeks of gestation and aged 18-45 years old will be enrolled. * Both normotensive and hypertensive (office sitting systolic BP 140-150 mmHg and/or diastolic BP 90-100 mmHg) pregnant women will be enrolled if they are not on any antihypertensive drug treatment. * We will enroll both nulliparous and multiparous women. * There is no restriction regarding race/ethnicity and socioeconomic status. * Women with a history of HDP will be allowed to participate. * Women taking low-dose aspirin will be allowed to participate and aspirin use will be documented. Exclusion Criteria: * Current multiple pregnancies (e.g., twins, triplets, etc.). * Known major fetal chromosomal or anatomical abnormalities diagnosed during the study. * Recurrent miscarriage (three or more, to avoid antiphospholipid antibody syndrome). * Office sitting BP \<100/55 mmHg or \>150/100 mmHg (for safety reasons). * Evidence of cardiovascular, pulmonary, or neurological diseases. * Diabetes mellitus (to avoid its effects on vascular endothelial function and sympathetic vasoconstriction). * Kidney disease (serum creatinine \>0.9 mg/dL). * Clinical known deep vein thrombosis, clinical symptoms and history of deep vein thrombosis, or dermatological lesions. * History of drug or alcohol abuse within the last 2 years. * Current tobacco use. * Pregnant women who do not have air conditioning at home during summer (for safety reasons).