The six minute walk test in pregnant women and in women of childbearing age – a reference range study

• Register: ANZCTR
• Last refreshed on: 21 August 2023
• Main ID: ACTRN12615000964516
• Date of registration: 15/09/2015
• Prospective Registration: Yes
• Primary sponsor: The Royal Women's Hospital
• Public title: The six minute walk test in pregnant women and in women of childbearing age – a reference range study
• Scientific title: The six minute walk test in pregnant women and in women of childbearing age – a reference range study
• Date of first enrolment: 16/12/2015
• Target sample size: 550
• Recruitment status: Completed
• URL: https://anzctr.org.au/ACTRN12615000964516.aspx
• Study type: Observational
• Study design: Purpose: Natural history;Duration: Cross-sectional;Selection: Defined population;Timing: Prospective;
• Phase: Not Applicable

Countries of recruitment

Australia, South Africa, United Kingdom

Contacts

• Name: A/Prof Alicia Dennis

• Name: A/Prof Alicia Dennis

Key inclusion & exclusion criteria

Inclusion criteria: Healthy pregnant nulliparous women will be defined as American Society of Anesthesiologists (ASA) Classification I or II, with no significant medical or surgical illnesses, and aged 18 - 40 years. Second trimester women will be recruited from 140 to 236 weeks gestation. Term pregnant women will be recruitment from 360 weeks gestation until delivery. Healthy non-pregnant nulliparous women will be defined as American Society of Anesthesiologists (ASA) Classification I or II, with no significant medical or surgical illnesses, and aged 18 - 40 years.
a. Women less than 24 weeks pregnant will be included if body mass index is less than or equal to 32 kg/m2 at the time of the study
b. Women equal to or greater than 36 weeks pregnant will be included if body mass index is less than 35 kg/m2 at the time of the study
c. Non-pregnant women will be included if body mass index is equal to or less than 30 kg/m2 at the time of the study

Exclusion criteria: Any woman with pre-existing conditions that limit ability to exercise (joint, muscle, bone, neurological), pre-existing or gestational diabetes, pre-existing or pregnancy acquired cardiovascular disease, multiple pregnancy, smokers, any woman in labour or postpartum and inability to consent to study.

a. Women less than 24 weeks pregnant will be excluded if body mass index is greater than 32 kg/m2 at the time of the study
b. Women equal to or greater than 36 weeks pregnant will be excluded if body mass index equal to or greater than 35 kg/m2 at the time of the study
c. Non-pregnant women will be excluded if body mass index is greater than 30 kg/m2 at the time of the study



Age minimum: 18 Years
Age maximum: 40 Years
Gender: Females

Health Condition(s) or Problem(s) studied

Cardiovascular - Normal development and function of the cardiovascular system

Public Health - Health service research

Pregnancy;
Pregnancy

Intervention(s)

The Six Minute Walk (6MWT) Test, conducted as specified by the National Heart Foundation of Australia, with two walk tests performed and this should take a maximum of 30 min to complete including the breaks.

The Incremental Shuttle Walk Test conducted as specified by "Holland AE, Spruit MA, Troosters T, et al. An official European Respiratory Society/American Thoracic Society technical standard: field walking tests in chronic respiratory disease. Eur Respir J 2014;44:1428-46." This test will take approximately 30 minutes and be conducted one-on-one by one of the trained research investigators (including a physiotherapist or trained research midwife).

Transthoracic echocardiography according to guidelines by the American Society of Echocardiography. This test will take approximately 15 minutes and be conducted one-on-one by one of the trained research investigators (including a trained obstetric anaesthetist (TTE trained) or cardiac sonographer).

Cardiopulmonary exercise testing (CPET) according to accepted guidelines "American Thoracic S, American College of Chest P. ATS/ACCP Statement on cardiopulmonary exercise testing. Am J Respir Crit Care Med 2003;167:211-77." This test will take approximately 1 hour and will be conducted using a stationary bicycle (cycle ergometer), one-on-one with the trained research and clinical team at Peter MacCallum Hospital.

Testing will occur over two separate days and will be conducted in women in the early pregnancy group of participants in the 6MWT study (healthy nulliparous pregnant women approximately less than 24 weeks gestation, no musculoskeletal problems, no pelvic floor problems – all outpatients). The two testing days are to occur within a seven-day period. On the first testing day participants will c

Primary Outcome(s)

This will be metres walked in six minutes (average of two tests with a 15 minute break to allow for return to baseline values – this will be confirmed by return to baseline heart rate).[At the end of the second six minute walk test completion]

Secondary Outcome(s)

Rating of Perceived Exertion (RPE) Category Scale (actual and expected) measured by answering questions to a structured questionnaire - National Heart Foundation of Australia[At the end of the six minute walk test ]

Cardiac output obtained by transthoracic echocardiography.
. [At rest before exercise testing]

Respiratory rate measured by counting the participants respiratory rate in 20 seconds and multiplying by 3[At the beginning and end of the 6 minute walk test]

Heart rate measured by the pulse oximeter[At the beginning and the end of the six minute walk test]

maximal oxygen utilisation capacity (VO2Max) obtained by CardioPulmonary Exercise Testing (CPET).
[At the end of CPET testing]

Blood pressure (BP) measured by automatic blood pressure device[At the beginning and the end of the second six minute walk test]

Distance walked in the incremental shuttle walk test.
. [at the end of the test]

Numerical value on dyspnoea scale (actual and expected) National Heart Foundation of Australia [At the end of the six minute walk test]

Oxygen saturation (SpO2) measured by a pulse oximeter[At the beginning and the end of the six minute walk test]

Secondary ID(s)

nil

Source(s) of Monetary Support

Australian and New Zealand College of Anaesthestists

The Royal Women's Hospital

Secondary Sponsor(s)

Chelsea & Westminster Hospital

Ethics review

Status: Approved
Approval date: 26/10/2015
Contact:

The Royal Women's Hospital Human Research Ethics Committee (EC00259)

Results

• Results available: Yes
• Date Posted: 15/08/2023
• Date Completed: 08/05/2022