[Altitude exposure and staying at high altitude in pregnancy: effects on the mother and fetus].

In this paper we review some effects of acute and short-term exposure to altitude on maternal and fetal cardio-pulmonary function. These effects may be seen during commercial aircraft flight or mountain ascent in cablecars. In addition cardio-pulmonary changes during maternal exercise at altitude are discussed. Altitudes up to 2 500 m are well tolerated by mother and fetus in uncomplicated pregnancies. Slight maternal exercise does not provoke fetal heart rate changes. However, in pregnancies at risk, for example because of maternal smoking, precaution with exposure to altitude is justified. Particularly at risk may be stewardesses if they continue their strenuous work while pregnant. Living at high altitude (more than 2 500 m) the lower oxygen partial pressure has some well known negative effects on mother and fetus. The importance of the various mechanisms of acclimatisation and adaptation to hypoxaemia, and other factors influencing reproduction when living at high altitude are reviewed and discussed.