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.
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)).
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.