Leg Heating for Complicated Pregnancy

Overseen By Qi Fu, MD, PhD

Age: 18 - 65

Sex: Female

Trial Phase: Academic

Sponsor: University of Texas Southwestern Medical Center

Must not be taking: Antihypertensives

Disqualifiers: Multiple pregnancies, Diabetes, Kidney disease, others

Compensation: Varies

Number of Visits: 28

Duration: 16 weeks

118 Participants Needed

What You Need to Know Before You Apply

What is the purpose of this trial?

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.

Will I have to stop taking my current medications?

The trial does not specify if you need to stop taking your current medications, but you cannot participate if you are on antihypertensive drugs. You can continue taking low-dose aspirin if you are already using it.

How does leg heating differ from other treatments for complicated pregnancy?

Leg heating is unique because it focuses on improving blood flow in the legs by applying heat, which may help alleviate symptoms of venous insufficiency (poor blood flow in the veins) during pregnancy. This approach is different from other treatments like compression stockings or medications, which aim to manage symptoms through pressure or chemical means. ^{1 2 3 4 5}

Who Is on the Research Team?

Qi Fu, MD, PhD

Principal Investigator

UT Southwestern Medical Center; Institute for Exercise and Environmental Medicine

Are You a Good Fit for This Trial?

This trial is for pregnant women with obesity, between 12-14 weeks of gestation. It aims to see if leg heating can reduce the risk of hypertensive disorders during pregnancy by improving blood vessel function and reducing overactive sympathetic nerves.

Inclusion Criteria

Both nulliparous and multiparous women will be enrolled

No restriction regarding race/ethnicity and socioeconomic status

I am an overweight woman, pregnant between 10-14 weeks, aged 18-45.

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)

Timeline for a Trial Participant

Screening

Participants are screened for eligibility to participate in the trial

2-4 weeks

Treatment

Participants perform home-based leg heating using a portable sauna blanket set at 65°C or 35°C, 4 times per week, 45 minutes per session

16 weeks

Baseline and 28-30 weeks of gestation evaluations

Follow-up

Participants are monitored for changes in vascular endothelial function and sympathetic vasoconstriction

4 weeks

What Are the Treatments Tested in This Trial?

Interventions

• Leg Heating

Trial Overview The study tests whether home-based leg heating using a sauna blanket can benefit vascular health in obese pregnant women. Participants are randomly assigned to either heat their legs at 65°C or use a control setting at 35°C, four times a week for 45 minutes over 16 weeks.

How Is the Trial Designed?

Group I: Sauna blanket set at 65°C Experimental Treatment 1 Intervention

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.

Group II: Sauna blanket set at 35°C Placebo Group 1 Intervention

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.

Who Is Running the Clinical Trial?

University of Texas Southwestern Medical Center

Lead Sponsor

Trials

1,102

Recruited

1,077,000+

Citations

1. France pubmed.ncbi.nlm.nih.gov

[Venous insufficiency of the lower limbs in pregnancy]. [2006]

2. Germany pubmed.ncbi.nlm.nih.gov

[Sonography as a screening examination method of the venous system in pregnancy. Comparative studies of the arm and leg vein system]. [2006]

3. Italy pubmed.ncbi.nlm.nih.gov

Management of deep venous thrombosis in the pregnant female. [2016]

4. France pubmed.ncbi.nlm.nih.gov

[Effects of electrostimulation (Veinoplus) on lower limbs venous insufficiency-related symptoms during pregnancy. Preliminary study]. [2009]

5. England pubmed.ncbi.nlm.nih.gov

Compression stocking prevents increased venous retrograde flow time in the lower limbs of pregnant women. [2021]