Resting Hemodynamics and Response to Exercise Using the 6-Minute Walk Test in Late Pregnancy

Pregnancy reference intervals and exertion and breathlessness ratings for the six minute walk test in healthy nulliparous people

Background

The Six Minute Walk Test (6MWT) is a simple, non-invasive, well-validated test that assesses cardiorespiratory fitness however is rarely used in pregnant people. It may have clinical utilization to assess fitness, breathing and exertion in pregnancy however no reference intervals exist for people 14+0 to 35+6 weeks gestation. We determined the reference intervals for distance walked for the 6MWT, including exertional and breathlessness ratings for this group.

Method

We conducted a prospective observational cohort study of 196 healthy nulliparous pregnant people in earlier pregnancy (EP) 14+0 to 23+6 weeks, and middle pregnancy (MP) 24+0 to 35+6 gestation, who performed a standardized 6MWT protocol including rating exertion and breathlessness (Rating Perceived Exertion (RPE) scale (1 none -15 maximal) and Modified Borg Dyspnea (MBD) scale (0 none - 10 maximal)).

Results

The mean ± SD distance walked was 548 ± 80.9 (EP) versus 547 ± 87.3 (MP) meters (m) P = 0.928. 6MWT reference intervals for the distance walked for the 6MWT were 392-704 m (EP) and 376-718 m (MP). Median (IQR) exertion and breathlessness ratings with exercise for the EP and MP group were 6 (4,7) and 0.5 (0,1) and 6 (4,8) and 0.5 (0,1) respectively. There were no adverse events.

Conclusion

The 6MWT is safe, feasible and acceptable in pregnant people. The reference intervals for the 6MWT are 392-704 m in people 14+0 to 23+6 weeks gestation and 376-718 m for people 24+0 to 35+6 weeks gestation. Exertion was light and breathlessness was just noticeable with the 6MWT.

Perioperative Exercise Testing in Pregnant and Non-Pregnant Women of Reproductive Age: A Systematic Review

BACKGROUND

Women have classically been excluded from the development of normal data and reference ranges, with pregnant women experiencing further neglect. The incidence of Caesarean section in pregnant women, and of general operative management in young women (both pregnant and non-pregnant), necessitates the formal development of healthy baseline data in these cohorts to optimise their perioperative management. This systematic review assesses the representation of young women in existing reference ranges for several functional exercise tests in common use to facilitate functional assessment in this cohort.

METHODS

Existing reference range data for the exercise tests the Six Minute Walk Test (6MWT), the Incremental Shuttle Walk Test (ISWT) and Cardiopulmonary Exercise Testing (CPET) in young women of reproductive age were assessed using the MEDLINE (Ovid) database, last searched December 2023. Results were comparatively tabulated but not statistically analysed given underlying variances in data.

RESULTS

The role of exercise testing in the perioperative period as an assessment tool, as well as its safety during pregnancy, was evaluated using 65 studies which met inclusion criteria.

CONCLUSION

There is a significant lack of baseline data regarding these tests in this population, especially amongst the pregnant cohort, which limits the application of exercise testing clinically.

Assessment of physical fitness during pregnancy: validity and reliability of fitness tests, and relationship with maternal and neonatal health - a systematic review

Objectives

To systematically review studies evaluating one or more components of physical fitness (PF) in pregnant women, to answer two research questions: (1) What tests have been employed to assess PF in pregnant women? and (2) What is the validity and reliability of these tests and their relationship with maternal and neonatal health?

Design

A systematic review.

Data sources

PubMed and Web of Science.

Eligibility criteria

Original English or Spanish full-text articles in a group of healthy pregnant women which at least one component of PF was assessed (field based or laboratory tests).

Results

A total of 149 articles containing a sum of 191 fitness tests were included. Among the 191 fitness tests, 99 (ie, 52%) assessed cardiorespiratory fitness through 75 different protocols, 28 (15%) assessed muscular fitness through 16 different protocols, 14 (7%) assessed flexibility through 13 different protocols, 45 (24%) assessed balance through 40 different protocols, 2 assessed speed with the same protocol and 3 were multidimensional tests using one protocol. A total of 19 articles with 23 tests (13%) assessed either validity (n=4), reliability (n=6) or the relationship of PF with maternal and neonatal health (n=16).

Conclusion

Physical fitness has been assessed through a wide variety of protocols, mostly lacking validity and reliability data, and no consensus exists on the most suitable fitness tests to be performed during pregnancy.

PROSPERO registration number

CRD42018117554.

Pregnancy Considerations for Patients With Interstitial Lung Disease

Advances in our understanding of interstitial lung disease (ILD) pathophysiology and natural history have led to the development of guidelines for the diagnosis and management of several of these complex diseases. The demographics of patients with ILD indicate the disease is not restricted to older adults. Connective tissue disease-associated ILD, familial pulmonary fibrosis, and post-COVID-19 fibrosis may affect women of child-bearing age. Recent trials have excluded pregnant women, thereby limiting the applicability of contemporary therapeutic advances to these patients. This review synthesizes the current knowledge of pregnancy outcomes in those with ILD, with a focus on connective tissue disease-associated ILD, and potential treatment implications for patients with ILD who are pregnant or considering pregnancy. Pregnancy considerations for patients with ILD include the need for preconception counseling and planning to ensure disease stability, medication and vaccination optimization, and multidisciplinary involvement of a patient's pulmonologist, obstetrician, and, when indicated, rheumatologist and genetic counselor. Evidence to date suggests that women with ILD can have safe and healthy pregnancies but that complications may occur in those with severe ILD.

Pregnancy in Pulmonary Arterial Hypertension: A Multidisciplinary Approach

Pulmonary arterial hypertension (PAH), a female predominant disease, carries a high maternal and fetal mortality in pregnancy despite improved insight and the development of novel therapies. The high risk is attributed to the adaptive changes that take place to promote healthy fetal development during pregnancy, which can adversely affect the already compromised right ventricle in patients with PAH. While in the prior era emphasis was placed on termination of pregnancy, here we will illustrate through a multidisciplinary approach and meticulous planning at an expert center, these high-risk women can undergo successful childbirth.

Self-reported (IFIS) versus measured physical fitness, and their associations to cardiometabolic risk factors in early pregnancy

Physical fitness is a strong marker of health, but objective fitness measurements are not always feasible. The International FItness Scale (IFIS) for self-reported fitness is a simple-to-use tool with demonstrated validity and reliability; however, validation in pregnancy needs to be confirmed. Also, its association with cardiometabolic health in pregnant women is unknown. Hence, we examined (1) the validity of the IFIS with objectively measured fitness, and (2) the associations of self-reported versus objectively measured cardiorespiratory fitness (CRF) and muscular strength with cardiometabolic risk factors in early pregnancy. Women (n = 303) from the HealthyMoms trial were measured at gestational week 14 for: CRF (6-min walk test); upper-body muscular strength (handgrip strength test); self-reported fitness (IFIS), body composition (air-displacement plethysmography); blood pressure and metabolic parameters (lipids, glucose, insulin). Higher self-reported fitness was associated with better measured fitness (ANOVA overall p < 0.01 for all fitness types), indicating the usefulness of the IFIS in pregnancy. Furthermore, higher self-reported overall fitness and CRF were associated with lower cardiometabolic risk scores (ANOVA p < 0.001), with similar results shown for measured CRF (ANOVA p < 0.001). The findings suggest that IFIS could be useful to stratify pregnant women in appropriate fitness levels on a population-based level where objective measurement is not possible.

Cardiopulmonary exercise testing during pregnancy

The goal of this review is to examine practical considerations when conducting cardiopulmonary exercise testing during pregnancy. In a clinical and research setting, cardiopulmonary exercise testing during pregnancy is valuable in identifying underlying cardiopulmonary conditions, stratifying the risk of adverse pregnancy outcomes, as well as establishing exercise tolerance/limitations. This review encompasses information regarding the unique physiological adaptations that occur throughout gestation (e.g., changes in resting heart rate, blood pressure, glucose, etc.) and how these adaptations impact the interpretation of physiological measurements. There are also key concerns that are unique to pregnant populations that should be considered when participating in exercise (i.e., fetus, ventilation, thermoregulation, urinary incontinence, low back pain, and pelvic girdle pain). This step-by-step review of cardiopulmonary exercise testing outlines pregnancy related adjustments to standardized methods (i.e., screening/documentation, pre- and post-test measurements, protocol specifics, modality selection, and fetal monitoring) which should be considered for the safety of both the participant and fetus. Currently, pregnancy specific exercise testing guidelines are lacking. Therefore, we will be discussing the limitations of current recommendations such as a safe cut off for resting heart rate and pregnancy specific test termination criteria.