PregnancyHITFLOWNCT04288479
Acute Effects of High Intensity Training in Pregnancy on Fetal Well-being and Blood Flow Distribution
A study testing Single high-intensity interval training session in people with Pregnancy, run by Norwegian University of Science and Technology at 1 site in Norway.
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… Read more about this study
- Who is it for?
- Ages 18 years and older, women only
- Conditions the study is for
- Pregnancy
- What is being tested?
- Single high-intensity interval training session
- Type of treatment
- Lifestyle or therapy programme
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 34 participants
- Where
- 1 siteNorway
- Study dates
- 23 Feb 2022to 23 Apr 2025
- Phase
- Interventional
- Are there results?
- None posted in the registry
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 years and older
- Women only
- No healthy volunteers
- Adult, Older adult
Who may be able to join
- pregnant, gestational week 22-36
- singleton fetus
- no known diseases
- capable of cycling on an ergometer bike
Who cannot join
- hypertension
- gestational diabetes mellitus
- any contraindication to exercise training
Trial locations and contacts
1 site in 1 country.
Norway1 site
Dept Circulation and Medical Imaging, EXCAR Exercise Lab
Trondheim
About this study
Official title: 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.
Read more
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.
- Conditions
- Pregnancy
- Being tested
- Single high-intensity interval training session
- Keywords
- Exercise, High Intensity Interval Training, Pregnancy Outcome, Placental Circulation, Fetal Blood, Heart Rate, Fetal
- Medical subject headings
- Motor Activity
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Single high-intensity interval training sessionBehavioural
Also called HIT
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.
| Study group | Role | What they receive |
|---|---|---|
| Doing a single HIT session in gestational week 22-36 | Experimental | Not described Receives: Behavioral: Single high-intensity interval training session |
What is being measured
The primary outcome is the main question the study is designed to answer.
blood flow in fetal veins
examined by Doppler ultrasound during 30 minutes
Measured: 1 day
blood flow in fetal arteries
examined by Doppler ultrasound during 30 minutes
Measured: 1 day
Secondary outcomes (7)
maternal heart rate
Measured: 1 dag
Fetal heart rate
Measured: 1 day
Umbilical vein diameter
Measured: 1 day
Maternal systolic blood pressure
Measured: 1 day
Maternal diastolic blood pressure
Measured: 1 day
Maternal body weight
Measured: 1 day
Maternal height
Measured: 1 day
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted28 Feb 2020
- Study start23 Feb 2022
- Primary completion23 Apr 2025
- Study completion23 Apr 2025
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for PregnancyStudies of the same condition, open and under way.
- More trials run by Norwegian University of Science and TechnologyThe sponsor's other registered studies.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase N/A
- Primary purpose
- Treatment
- Allocation
- Not applicable
- Intervention model
- Single group
- Model description
- before-after intervention effect measurement
- Masking
- None (open label)
- Enrolment
- 34 participants (actual)
Sponsor and investigators
- Lead sponsor
- Norwegian University of Science and Technology
- Sponsor type
- University, hospital or other
- Collaborators
- St. Olavs Hospital
- Responsible party
- Sponsor
- Investigators
- Kjell Å Salvesen, md prof, Study director, St Olavs Hospital, Dept of Obstetrics and GynecologyTrine Moholdt, phd, Principal investigator, Norwegian University of Science and Technology
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT04288479
- Sponsor's protocol ID
- 62993
- Acronym
- HITFLOW
- Status last verified
- May 2025
- First submitted
- 26 Feb 2020
- Last updated
- 21 May 2025
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No
Study at a glance
From the registry record, last updated by the sponsor on 21 May 2025. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Acute Effects of HIT on Fetal Well-being and Blood Flow Distribution - a Pilot Study
- ClinicalTrials.gov ID
- NCT04288479
- Acronym / sponsor ID
- HITFLOW / 62993
- Conditions
- Pregnancy
- Keywords
- Exercise, High Intensity Interval Training, Pregnancy Outcome, Placental Circulation, Fetal Blood, Heart Rate, Fetal
- Study type
- Interventional
- Recruitment status
- Completed
- Enrolment
- 34 participants (actual)
- Lead sponsor
- Norwegian University of Science and TechnologyUniversity, hospital or other
- Collaborators
- St. Olavs Hospital
- Study start
- 23 Feb 2022 (actual)
- Primary completion
- 23 Apr 2025 (actual)
- Study completion
- 23 Apr 2025 (actual)
- First posted
- 28 Feb 2020 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
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 design
- Primary purpose
- Treatment
- Allocation
- Not applicable
- Intervention model
- Single group
- Masking
- None (open label)
- Number of arms
- 1
- Model description
- before-after intervention effect measurement
| Arm | Type | Receives |
|---|---|---|
| Doing a single HIT session in gestational week 22-36 | Experimental | Behavioral: Single high-intensity interval training session |
Who may qualify
- Ages
- 18 years and older
- Sex
- Female only
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (4 listed)
- pregnant, gestational week 22-36
- singleton fetus
- no known diseases
- capable of cycling on an ergometer bike
Key exclusion criteria (3 listed)
- hypertension
- gestational diabetes mellitus
- any contraindication to exercise training
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Single high-intensity interval training sessionAlso: HIT10 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. | Behavioural | Doing a single HIT session in gestational week 22-36 |
Primary outcome
blood flow in fetal veins
Time frame: 1 day
examined by Doppler ultrasound during 30 minutes
blood flow in fetal arteries
Time frame: 1 day
examined by Doppler ultrasound during 30 minutes
7 secondary outcomes
maternal heart rate
Time frame: 1 dag
Fetal heart rate
Time frame: 1 day
Umbilical vein diameter
Time frame: 1 day
Maternal systolic blood pressure
Time frame: 1 day
Maternal diastolic blood pressure
Time frame: 1 day
Maternal body weight
Time frame: 1 day
Maternal height
Time frame: 1 day
Results and safety
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 21 May 2025.
- Individual participant dataSharing planned: No
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
Kjell Å Salvesen, md prof study director
St Olavs Hospital, Dept of Obstetrics and Gynecology
Trine Moholdt, phd principal investigator
Norwegian University of Science and Technology
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing Single high-intensity interval training session in people with Pregnancy, run by Norwegian University of Science and Technology at 1 site in Norway.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 4 inclusion and 3 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: finished, as of the sponsor's last update on 21 May 2025. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in Norway. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
blood flow in fetal veins (time frame: 1 day). The study lists 2 primary outcomes in all. It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 21 May 2025.