Oxygen saturation response to exercise in healthy pregnant women: a simple protocol and normal range

Abstract

Summary: Measurement of oxygen saturation on excercise, using a pulse oximeter, has been advocated in the assessment of women with shortness of breath in pregnancy. However, there is currently no standard protocol for this. The aims of this study were to determine the normal range for oxygen saturation at rest and on moderate exercise in healthy women from 24 weeks gestation and to evaluate a simple, widely applicable exercise protocol in which women walked at their own pace for 100 metres then up two flights of stairs. The protocol achieved 60-85% maximum predicted heart rate in 99% of women at a median gestation of 31 þ3 weeks, with a wide range of Hb and BMI. There was a mean 0.3% fall in oxygen saturation on exertion but oxygen saturation did not fall below 95% in any of the women.

Impact of Aerobics Exercise Training on the Pulse Oximetry of Pregnant Women in a Nigerian Teaching Hospital

“…Moderate exercise is safe in pregnancy" [27] and "it has been recommended that a maximal heart rate of 60-70% maximum predicted is appropriate for women who were previously sedentary and 60-90% maximum predicted for those who were fit prior to pregnancy" [28]. "The value of 60-80% maximum predicted heart rate was chosen as the target in this study in order to provide a significant cardiovascular challenge, likely to reveal any abnormality, while avoiding over-exertion" [29].…”

Physiological Changes and Cardiovascular Investigations in Pregnancy

“…A normal sitting PaO 2 in healthy women in first and second trimesters is 105-106 mmHg, and 101-106 mmHg in third trimester [8]. Mean oxygen saturation at rest in a study of 100 healthy pregnant women in second and third trimester was 9860.95% (range 96-100%) [9]. Following exercise (100 m walking on flat, then immediately up 24 steps) mean oxygen saturation was 97.761% (range 95-100%), a mean fall in oxygen saturation of 0.32%.…”