Leg heating for pregnant women with overweight or obesity

Vascular and Neural Mechanisms of Chronic Leg Heating in Pregnant Women With Obesity

This trial will try repeated leg heating to improve blood vessel function and lower the risk of high blood pressure in pregnant women with overweight or obesity.

Quick facts

• Phase: NA
• Study type: Interventional
• Enrollment: 118 (estimated)
• Ages: 18 Years to 45 Years
• Sex: Female
• Sponsor: University of Texas Southwestern Medical Center (other)
• Locations: 1 site (Dallas, Texas)
• Trial ID: NCT06932250 on ClinicalTrials.gov

What this trial studies

Women with pre-pregnancy BMI ≥25 and gestational age 10–14 weeks will receive repeated regional leg heating sessions to test effects on maternal vascular function. The intervention aims to increase nitric oxide availability, reduce endothelin-1, and blunt sympathetic vasoconstriction—mechanisms linked to hypertensive disorders of pregnancy. Investigators will measure endothelial function, blood pressure, and markers of sympathetic activity and vasoactive pathways before and after the intervention. The approach is intended as a low-cost, well-tolerated, non-exercise alternative to improve vascular health during pregnancy.

Who should consider this trial

Good fit: Pregnant women aged 18–45, 10–14 weeks gestation, with pre-pregnancy BMI ≥25 who are not taking antihypertensive medications are ideal candidates.

Not a fit: Women with multiple pregnancies, known major fetal abnormalities, recurrent miscarriage history, or very low or very high baseline blood pressure (outside safety limits) are unlikely to benefit or be eligible.

Why it matters

Potential benefit: If successful, this could improve maternal vascular function and lower the chance of developing hypertensive disorders during pregnancy.

How similar studies have performed: Whole-body heat exposure and exercise have improved vascular function in non-pregnant people, but regional leg heating in pregnant women is a novel and largely untested approach.

Eligibility criteria

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).

Where this trial is running

Dallas, Texas

• UT Southwestern Medical Center; Institute for Exercise and Environmental Medicine — Dallas, Texas, United States (RECRUITING)

Study contacts

• Principal investigator: Qi Fu, MD, PhD — UT Southwestern Medical Center; Institute for Exercise and Environmental Medicine
• Study coordinator: Qi Fu, MD, PhD

Conditions: High-risk Pregnancy, Pregnancy, Obesity, Heat therapy, Vascular function, Sympathetic neural control, Blood pressure