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Evaluating Pathophysiological Mechanisms of Acute and Chronic Heat Stress on Maternal and Fetal Health

NCT07326176 · Status: COMPLETED · Phase: NA · Type: INTERVENTIONAL · Enrollment: 24

Last updated 2026-01-08

No results posted yet for this study

Summary

This study examined the effects of environmental heat and physical work on maternal thermoregulation and fetal physiology in late pregnancy. Twenty-four healthy pregnant women at 28-32 weeks of gestation completed four randomized and counterbalanced 3-hour experimental scenarios combining two thermal conditions (temperate 20 °C and warm 30 °C, both at 45% relative humidity, shaded) and two physical workload intensities (light and moderate treadmill walking). Each scenario included 1 hour of passive seated exposure, 1 hour of treadmill walking, and 1 hour of seated recovery. Maternal thermoregulatory, cardiovascular, perceptual, and hydration responses were monitored continuously, while fetal heart rate and Doppler-derived indices of uterine, umbilical, and middle cerebral artery blood flow were assessed at baseline, end of passive exposure, end of work, and end of recovery. The aims of the study were: (1) to characterize maternal physiological and perceptual responses to heat exposure and physical work; (2) to determine whether maternal physiological heat strain directly affects fetal cardiovascular strain and maternal-fetal hemodynamics; and (3) to examine whether maternal characteristics, particularly body mass index and age, influence maternal thermoregulatory responses and fetal susceptibility to heat stress.

Conditions

  • Thermally Neutral Condition With Light-intensity Work
  • Thermally Neutral Condition With Moderate-intensity Work
  • Warm Condition With Light-intensity Work
  • Warm Condition With Moderate-intensity Work

Interventions

OTHER

Heat and Physical Work Exposure Protocol

A controlled 3-hour environmental chamber protocol consisting of 1 hour of passive seated exposure, 1 hour of treadmill walking at prescribed light or moderate intensities (alternating between 2-3 METs or 3-4 METs every 10 minutes), and 1 hour of seated recovery. Each session was conducted under either temperate (20 °C, 45% relative humidity, shaded) or warm (30 °C, 45% relative humidity, shaded) environmental conditions. Environmental settings, workload intensity, and timing were standardized across all participants.

Sponsors & Collaborators

  • University of Thessaly

    lead OTHER

Principal Investigators

  • Leonidas Ioannou, PhD · University of Thessaly

Study Design

Allocation
RANDOMIZED
Purpose
BASIC_SCIENCE
Masking
NONE
Model
CROSSOVER

Eligibility

Min Age
18 Years
Sex
FEMALE
Healthy Volunteers
Yes

Timeline & Regulatory

Start
2024-05-15
Primary Completion
2024-08-15
Completion
2024-08-15

Countries

  • Greece

Study Locations

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Read the full study record

This page highlights key information. For complete eligibility criteria, study locations, investigator contacts, and the full protocol, visit the original record on ClinicalTrials.gov.

View NCT07326176 on ClinicalTrials.gov