Acute Effects of High Intensity Training in Pregnancy on Fetal Well-being and Blood Flow Distribution (HITFLOW)

Acute Effects of HIT on Fetal Well-being and Blood Flow Distribution - a Pilot Study

Pregnant women are recommended to be physically active ≥150 min/week, but <15% of Norwegian women attain this goal. Several well-designed studies on lifestyle interventions focusing primarily on exercise training in overweight/obese pregnant women have reported disappointing outcomes with regard to maternal glycemic control, gestational weight gain and infant outcomes. Low adherence to the training program was found to be a problem; the participants did not enjoy the exercise program and had difficulties scheduling time to exercise. Pregnant women also report that they are not sure what exercises are safe during pregnancy.

High intensity interval training (HIT), defined as short periods of intense activity separated by low-intensity breaks, has proved to induce superior improvements in insulin sensitivity and fitness compared with continuous moderate intensity training in individuals at increased risk for cardiometabolic diseases. Even short-term (6 weeks) HIT with brief (15-60 sec) work-bouts and a total time commitment of <45 min per week, improves insulin sensitivity similar to that attained after 6 months of traditional endurance training.

HIT is feasible and enjoyable for individuals with low fitness level and with obesity.

HIT is therefore a highly potent intervention that elicits important changes in a range of clinically relevant health outcomes in reproductive-aged women.

This study will investigate fetal responses to a single bout of HIT. Preliminary data of the investigators suggest that HIT does not negatively influence fetal heart rate. Others have reported that uterine and umbilical blood flow are not changed during or following acute exercise. However, no previous study has determined the acute effect of HIT on uterine blood flow and there are no studies investigating the fetal blood flow distribution in response to exercise. Since the relative distribution of blood to the fetal liver is associated with newborn adiposity, fetal blood flow distribution in response to exercise can provide insight about the effect of maternal exercise on offspring health.

Study Overview

• Status: Recruiting
• Conditions: Pregnancy
• Intervention / Treatment: Behavioral: Single high-intensity interval training session

• Study Type: Interventional
• Enrollment (Estimated): 30
• Phase: Not Applicable

Contacts and Locations

• Study Contact: Name: Trine Moholdt, phd; Phone Number: +47 73412007; Email: trine.moholdt@ntnu.no
• Study Contact Backup: Name: Guro Rosvold; Email: guro.rosvoldt@ntnu.no

Study Locations

• Norway
  • Trondheim, Norway
    • Recruiting
    • Dept Circulation and Medical Imaging, EXCAR Exercise Lab
    • Contact: Trine Moholdt, phd; Email: trine.moholdt@ntnu.no

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years and older (Adult, Older Adult)
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

• pregnant, gestational week 22-36
• singleton fetus
• no known diseases
• capable of cycling on an ergometer bike

Exclusion Criteria:

• hypertension
• gestational diabetes mellitus
• any contraindication to exercise training

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: N/A
• Interventional Model: Single Group Assignment
• Masking: None (Open Label)

Number of Arms

1

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Doing a single HIT session in gestational week 22-36	Behavioral: Single high-intensity interval training session; 10 minutes warming up at low-to-moderate intensity, 8x30 seconds high intensity interval training with fetal heart rate measurement after each 30 second work-bout, 2 minutes recovery at low-to-moderate intensity. Continuous monitoring of maternal heart rate.; Other Names: HIT

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
blood flow in fetal veins	examined by Doppler ultrasound during 30 minutes	1 day
blood flow in fetal arteries	examined by Doppler ultrasound during 30 minutes	1 day

Secondary Outcome Measures

Outcome Measure	Time Frame
maternal heart rate	1 dag
Fetal heart rate	1 day
Umbilical vein diameter	1 day
Maternal systolic blood pressure	1 day
Maternal diastolic blood pressure	1 day
Maternal body weight	1 day
Maternal height	1 day

Collaborators and Investigators

• Sponsor: Norwegian University of Science and Technology
• Collaborators: St. Olavs Hospital
• Investigators: Study Director: Kjell Å Salvesen, md prof, St Olavs Hospital, Dept of Obstetrics and Gynecology; Principal Investigator: Trine Moholdt, phd, Norwegian University of Science and Technology

Study record dates

Study Major Dates

• Study Start (Actual): February 23, 2022
• Primary Completion (Estimated): January 1, 2025
• Study Completion (Estimated): February 1, 2025

Study Registration Dates

• First Submitted: February 26, 2020
• First Submitted That Met QC Criteria: February 26, 2020
• First Posted (Actual): February 28, 2020

Study Record Updates

• Last Update Posted (Actual): April 3, 2024
• Last Update Submitted That Met QC Criteria: April 2, 2024
• Last Verified: April 1, 2024

More Information

Terms related to this study

• Keywords: Exercise; High Intensity Interval Training; Pregnancy Outcome; Placental Circulation; Fetal Blood; Heart Rate, Fetal
• Other Study ID Numbers: 62993

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No
• product manufactured in and exported from the U.S.: No