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

Pregnancy Clinical Trial

— HITFLOW  

Official title:

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

Clinical Trial Details — Status: Recruiting

Administrative data

• NCT number: NCT04288479
• Other study ID #: 62993
• Status: Recruiting
• Phase: N/A
• Start date: February 23, 2022
• Est. completion date: February 2025

Study information

• Verified date: April 2024
• Source: Norwegian University of Science and Technology
• Contact: Trine Moholdt, phd
• Phone: +47 73412007
• Email: trine.moholdt[@]ntnu.no
• Is FDA regulated: No
• Study type: Interventional

Clinical Trial Summary

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.

Recruitment information / eligibility

• Status: Recruiting
• Enrollment: 30
• Est. completion date: February 2025
• Est. primary completion date: January 2025
• Accepts healthy volunteers: No
• Gender: Female
• Age group: 18 Years and older

Eligibility

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

Related Conditions & MeSH terms

• Pregnancy

Intervention

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.

Locations

Country	Name	City	State
Norway	Dept Circulation and Medical Imaging, EXCAR Exercise Lab	Trondheim

Sponsors (2)

Lead Sponsor	Collaborator
Norwegian University of Science and Technology	St. Olavs Hospital

Country where clinical trial is conducted

Norway, 

Outcome

Type	Measure	Description	Time frame	Safety issue
Primary	blood flow in fetal veins	examined by Doppler ultrasound during 30 minutes	1 day
Primary	blood flow in fetal arteries	examined by Doppler ultrasound during 30 minutes	1 day
Secondary	maternal heart rate		1 dag
Secondary	Fetal heart rate		1 day
Secondary	Umbilical vein diameter		1 day
Secondary	Maternal systolic blood pressure		1 day
Secondary	Maternal diastolic blood pressure		1 day
Secondary	Maternal body weight		1 day
Secondary	Maternal height		1 day