Evaluating Pathophysiological Mechanisms of Acute and Chronic Heat Stress on Maternal and Fetal Health
试验速览
- 阶段
- 不适用
- 状态
- 已完成
- 入组人数
- 24
- 试验地点
- 1
- 主要终点
- Maternal Core Body Temperature
研究概览
简要总结
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.
研究设计
- 研究类型
- Interventional
- 分配方式
- Randomized
- 干预模型
- Crossover
- 主要目的
- Basic Science
- 盲法
- None
入排标准
- 年龄范围
- 18 Years 至 —（Adult, Older Adult）
- 性别
- Female
- 接受健康志愿者
- 是
入选标准
- •Healthy pregnant women between 28 and 32 weeks of gestation
- •Singleton pregnancy
- •Habitually heat-acclimatized, defined as daily exposure to outdoor environmental conditions equal to or warmer than those used in the study
- •Able to perform treadmill walking at light and moderate intensities
- •Willing and able to attend all laboratory sessions
- •Provided written informed consent
- •Age 18 years or older
排除标准
- •Multiple pregnancy (e.g., twins, triplets)
- •Chronic medical conditions, including but not limited to:
- •Hypertension
- •Obstetric complications, including:
- •Pre-eclampsia
- •Severe anemia
- •Acute infections, including urinary tract infection
- •Any contraindication to exercise based on the Physical Activity Readiness for Pregnancy (PARmed-X for Pregnancy) checklist
- •Inability to comply with the study procedures or scheduled visits
- •Any condition deemed by investigators to compromise participant safety or data integrity
研究组 & 干预措施
Temperate-Light
Participants were exposed to a temperate environment (20 °C, 45% relative humidity, shaded) for a 3-hour protocol consisting of 1 hour passive seated exposure, 1 hour of light-intensity treadmill walking (alternating between 2 and 3 METs [Metabolic Equivalents] every 10 minutes), and 1 hour seated recovery.
干预措施: Heat and Physical Work Exposure Protocol (Other)
Temperate-Moderate
Participants were exposed to a temperate environment (20 °C, 45% relative humidity, shaded) for a 3-hour protocol consisting of 1 hour passive seated exposure, 1 hour of moderate-intensity treadmill walking (alternating between 3 and 4 METs every 10 minutes), and 1 hour seated recovery.
干预措施: Heat and Physical Work Exposure Protocol (Other)
Warm-Light
Participants were exposed to a warm environment (30 °C, 45% relative humidity, shaded) for a 3-hour protocol consisting of 1 hour passive seated exposure, 1 hour of light-intensity treadmill walking (alternating between 2 and 3 METs every 10 minutes), and 1 hour seated recovery.
干预措施: Heat and Physical Work Exposure Protocol (Other)
Warm-Moderate
Participants were exposed to a warm environment (30 °C, 45% relative humidity, shaded) for a 3-hour protocol consisting of 1 hour passive seated exposure, 1 hour of moderate-intensity treadmill walking (alternating between 3 and 4 METs every 10 minutes), and 1 hour seated recovery.
干预措施: Heat and Physical Work Exposure Protocol (Other)
结局指标
主要结局
Maternal Core Body Temperature
时间窗: Continuously recorded throughout each 3-hour experimental session (baseline, 1-hour passive exposure, 1-hour physical work, and 1-hour recovery).
Core body temperature continuously assessed using an ingestible telemetric temperature capsule to quantify maternal thermoregulatory responses to different combinations of environmental heat (20 °C vs 30 °C) and physical workload (light vs moderate).
Maternal Physiological Strain Index
时间窗: Continuously calculated throughout each 3-hour experimental session (baseline, passive exposure, physical work, and recovery).
Physiological Strain Index (0-10 scale) calculated from core body temperature and heart rate to quantify overall maternal physiological heat strain under different environmental and workload combinations.
Fetal Heart Rate
时间窗: Each 3-hour session: 0 min (baseline), 60 min (end of passive exposure), 120 min (end of physical work), 180 min (end of recovery).
Fetal heart rate assessed using obstetric ultrasound to evaluate fetal cardiovascular responses to maternal exposure to different environmental temperatures and physical workload intensities.
Uterine Artery Pulsatility Index (PI)
时间窗: Each 3-hour session: 0 min (baseline), 60 min (end of passive exposure), 120 min (end of physical work), 180 min (end of recovery).
Pulsatility Index of the left and right uterine arteries measured by Doppler ultrasound to assess uteroplacental vascular resistance under different environmental and workload conditions.
Uterine Artery Resistive Index (RI)
时间窗: Each 3-hour session: 0 min (baseline), 60 min (end of passive exposure), 120 min (end of physical work), 180 min (end of recovery).
Resistive Index of the left and right uterine arteries measured by Doppler ultrasound to assess uteroplacental vascular resistance under different environmental and workload conditions.
Umbilical Artery Pulsatility Index
时间窗: Each 3-hour session: 0 min (baseline), 60 min (end of passive exposure), 120 min (end of physical work), 180 min (end of recovery).
Pulsatility Index of the umbilical artery measured by Doppler ultrasound to evaluate fetoplacental blood flow in response to maternal heat exposure and physical work.
Umbilical Artery Resistive Index
时间窗: Each 3-hour session: 0 min (baseline), 60 min (end of passive exposure), 120 min (end of physical work), 180 min (end of recovery).
Resistive Index of the umbilical artery measured by Doppler ultrasound to evaluate fetoplacental blood flow in response to maternal heat exposure and physical work.
Middle Cerebral Artery Pulsatility Index
时间窗: Each 3-hour session: 0 min (baseline), 60 min (end of passive exposure), 120 min (end of physical work), 180 min (end of recovery).
Pulsatility Index of the fetal middle cerebral artery measured by Doppler ultrasound to assess fetal cerebral vascular responses to maternal heat strain.
Middle Cerebral Artery Resistive Index
时间窗: Each 3-hour session: 0 min (baseline), 60 min (end of passive exposure), 120 min (end of physical work), 180 min (end of recovery).
Resistive Index of the fetal middle cerebral artery measured by Doppler ultrasound to assess fetal cerebral vascular responses to maternal heat strain.
Composite Maternal-Fetal Hemodynamic Ratios (cerebroplacental ratio)
时间窗: Each 3-hour session: 0 min (baseline), 60 min (end of passive exposure), 120 min (end of physical work), 180 min (end of recovery).
Cerebroplacental ratio calculated using artery Doppler measurements to characterize maternal-fetal hemodynamics and fetal strain under different environmental and workload conditions.
Composite Maternal-Fetal Hemodynamic Ratios (Uteroplacental:cerebral PI ratio)
时间窗: Each 3-hour session: 0 min (baseline), 60 min (end of passive exposure), 120 min (end of physical work), 180 min (end of recovery).
Uteroplacental:cerebral PI ratio calculated using artery Doppler measurements to characterize maternal-fetal hemodynamics and fetal strain under different environmental and workload conditions.
Composite Maternal-Fetal Hemodynamic Ratios (cerebrouterine PI ratio)
时间窗: Each 3-hour session: 0 min (baseline), 60 min (end of passive exposure), 120 min (end of physical work), 180 min (end of recovery).
Cerebrouterine PI ratio calculated using artery Doppler measurements to characterize maternal-fetal hemodynamics and fetal strain under different environmental and workload conditions.
次要结局
- Maternal Skin Temperature(Continuously recorded throughout each 3-hour experimental session (baseline, passive exposure, physical work, and recovery).)
- Maternal Skin Blood Flow(Continuously recorded throughout each 3-hour experimental session (baseline, passive exposure, physical work, and recovery).)
- Maternal Heart Rate(Continuously recorded throughout each 3-hour experimental session (baseline, passive exposure, physical work, and recovery).)
- Maternal Local Sweat Rate(Continuously recorded throughout each 3-hour experimental session (baseline, passive exposure, physical work, and recovery).)
- Maternal Arterial Blood Pressure(Measured at baseline and every 30 minutes during each 3-hour experimental session.)
- Thermal Sensation(Measured at baseline and every 30 minutes throughout each 3-hour experimental session (passive exposure, physical work, and recovery).)
- Rating of Perceived Exertion (RPE)(Measured at baseline and every 30 minutes throughout each 3-hour experimental session (passive exposure, physical work, and recovery).)
- Thermal Comfort(Measured at baseline and every 30 minutes throughout each 3-hour experimental session (passive exposure, physical work, and recovery).)
研究者
Leonidas G. Ioannou
Principal Investigator
University of Thessaly