Recruiting

Leg Heating

Sponsor:

University of Texas Southwestern Medical Center

Code:

NCT06932250

Conditions

High-risk Pregnancy

Eligibility Criteria

Sex: Female

Age: 18 - 45

Healthy Volunteers: Accepted

Interventions

Leg heating

Study Details

Brief summary:

Obesity is a major risk factor for hypertensive disorders of pregnancy (HDP). The underlying mechanisms are largely unclear, but maternal vascular endothelial dysfunction is likely involved. Endothelial dysfunction in HDP could be attributed to 1) alterations in the L-arginine/nitric oxide (NO) pathway, and 2) an increase in endothelin-1 (ET-1). Additionally, augmented sympathetic vasoconstriction may also contribute to HDP. Chronic (repeated) whole-body heat exposure has been shown to increase NO bioavailability, decrease ET-1, and cause functional and structural adaptations in the vasculature. All these can improve vascular function, attenuate sympathetic (re)activity, lower blood pressure (BP), and reduce cardiovascular risk in non-pregnant individuals. Whether this is also true after regional (leg) heating in high-risk pregnant women is unknown. The investigators' central hypothesis is that chronic leg heating will be effective in improving vascular endothelial function and attenuating sympathetic vasoconstriction, leading to a reduction of the risk for HDP in pregnant women with obesity. The overarching goal of this proposal is to determine the vascular and neural effects of chronic leg heating in obese pregnancy. The study team plans to enroll pregnant women with obesity between 12-14 weeks of gestation and randomly assign them to either an intervention group or a control group (1:1 ratio). Participants in the intervention group will perform 16 weeks of home-based leg heating using a portable sauna blanket up to the hip (temperature of the blanket will be set at 65°C, 4 times/week, 45 min/session), whereas women in the control group will set the temperature of the blanket at 35°C at the same frequency and duration. Participants will be evaluated at baseline and then at 28-30 weeks of gestation. Aim 1 will determine the effects of chronic leg heating on maternal vascular function and surrogate markers of HDP. Aim 2 will determine the effects of chronic leg heating on sympathetic vasoconstriction and BP. Findings from this project will provide insight on the extent and potential mechanisms of how chronic leg heating works for improving vascular endothelial function and sympathetic vasoconstriction in pregnant women with obesity. Results obtained will set a foundation for future large multicenter clinical trials to determine the efficacy and generalizability of home-based leg heat therapy as a safe, ease-of-use, cost-effective, and non-drug approach for reducing the risk of HDP.

Conditions

High-risk Pregnancy

Study ID

NCT06932250

Start date

Aug 1, 2025

Status verified date

Apr, 2026

Completion date

Apr 30, 2030

Anticipated

Primary completion date

Jan 31, 2030

Anticipated

Eligibility Criteria

Eligibility Criteria

Sex: Female

Age: 18 - 45

Healthy Volunteers: Accepted

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).

Study Design

Enrollment

118 participants

Anticipated

Allocation

Randomized

Intervention Model

Parallel Assignment

Primary purpose

Other

Interventions and Outcome Measures

Arms

experimental: Sauna blanket set at 65°C

The temperature of the sauna blanket will be set at 65°C and participants will perform home-based leg heating 4 times per week, 45 minutes per session.

placebo comparator: Sauna blanket set at 35°C

The temperature of the sauna blanket will be set at 35°C and participants will perform home-based leg heating 4 times per week, 45 minutes per session.

Interventions

Leg heating

Participants will perform home-based leg heating using a portable sauna blanket set at different temperature.

Primary outcome measure

  • Change in vascular endothelial function [ Time Frame: Baseline, 16 weeks after leg heating ]
  • Change in sympathetic neural control [ Time Frame: Baseline, 16 weeks after leg heating ]
  • Change in sympathetic vascular transduction [ Time Frame: Baseline, 16 weeks after leg heating ]

Central Contacts and Locations

Central contacts

Qi Fu, MD, PhD

214-345-8125QiFu@TexasHealth.org

Monique Roberts-Reeves, RN

214-345-4656MoniqueRoberts-Reeves@TexasHealth.org

Locations

UT Southwestern Medical Center; Institute for Exercise and Environmental Medicine

Recruiting

Dallas, Texas, United States, 75231

Contacts

Monique Roberts-Reeves, RN

214-345-4656MoniqueRoberts-Reeves@TexasHealth.org

More Information

Sponsor

University of Texas Southwestern Medical Center

Last update posted

Apr 17, 2026

Last verified

Apr, 2026

Keywords

  • Pregnancy
  • Obesity
  • Heat therapy
  • Vascular function
  • Sympathetic neural control
  • Blood pressure

Trial information was received from ClinicalTrials.gov and was last updated on 2026-09-09. This information was provided to ClinicalTrials.gov by University of Texas Southwestern Medical Center on 2026-04-17.