In 2018, a fetus was taken up to Everest Base Camp and while this is noteworthy on its own, physiological parameters were tracked of the mother-to-be.

The medical literature, blogs, and magazines are stuffed with dos and don’ts during pregnancy. Pilates during pregnancy? Do. Taking your unborn baby up to Everest Base Camp (5,364 m)? Probably don’t. Most pregnancy guidelines recommend two things concerning exercise and altitude. Firstly, for the majority of pregnant women, >30 min of moderate-intensity exercise is advised on most days of the week. Secondly, it’s advised to avoid exercise at altitudes (>1,800m). Furthermore, a section of Auerbach’s Wilderness Medicine, states that the fetus may tolerate acute hypobaric hypoxia at high altitude during a low-risk pregnancy, but that these studies have been performed only up to 3,700m. Also, it is well-established that highlanders are predisposed to pregnancy-related problems, such as pre-eclampsia, hypertension, and low-birth-weight infants.

In 2018, a 28-year-old third-trimester pregnant Sherpa took her pregnancy to a whole new level. She ascended to Everest Base Camp (~5,300 m), where she engaged in vigorous physical activity for 250 to 300 minutes daily. During this ascent, and also during another ascent with a similar profile ~10 months postpartum, there were no apparent maternal, fetal, or neonatal complications. Additionally, there were no signs of Acute Mountain Sickness (Lake Louis Score = 0). The lowest measured arterial oxygen concentration (PaO2) was 86 mmHg at 5,160 meters, she remained normotensive, and normal responses to altitude were observed (increased ventilation, hypocapnia, and hemodilution). She gave birth to a 3.2 kg baby girl at ~42 weeks gestation, by emergency cesarean section because of a nuchal cord and associated fetal distress. This case study performed by a collaboration of researchers from the University of Alberta, Canada, the Department of Physiology, University College Cork, the research participant, and Sherpa guide team, provides new insights into exercise and altitude travel during pregnancy and raises new questions. For instance, what are the tolerable limits of exercise and altitude that do not compromise fetus wellbeing, how is this different for lowlanders and high-altitude natives, and does exercise at altitude reduce pregnancy-related problems?

While the data collection of this study is unique, pregnant women at altitude are more common than might be expected. Keyes, Hackett, and Luks performed a survey to evaluate whether women engage in outdoor activities and high-altitude travel during pregnancy in the US. Their results showed that women traveled to high altitudes in over half of the pregnancies (some up to >6000 m), most did not receive counseling, and rates of miscarriage and most other complications were similar between pregnancies with and without travel above 2440 m. However, high altitude exposure was a risk factor for preterm labor and supplemental oxygen at birth. If this sample survey is representative of the general population may be questioned, since some participants continued smoking, alcohol use (26%), or participated in activities like BASE jumping and skydiving during pregnancy. Also, all data were self-reported.

Disclaimer: the information in this article is not intended or implied to be a substitute for professional medical advice, diagnosis, or treatment. Outdoor Medicine offers medical support and advice for this matter.

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Literature

1. Davenport, M.H., et al., Extreme pregnancy: maternal physical activity at Everest Base Camp. J Appl Physiol (1985), 2018. 125(2): p. 580-585.
2. Jean, D. and L.G. Moore, Travel to high altitude during pregnancy: frequently asked questions and recommendations for clinicians. High Alt Med Biol, 2012. 13(2): p. 73-81.
3. Auerbach, P.S., Wilderness medicine Seventh Edition. 2017, Philadelphia: Elsevier/Mosby.
4. Keyes, L. E., Hackett, P. H., & Luks, A. M. (2016, June 15). Outdoor activity and high altitude exposure during pregnancy: A survey of 459 pregnancies. Wilderness & Environmental Medicine. Retrieved September 18, 2022.