Herber t Juch, Mar tin Gauster
Te r a t o g e n e s R i s i k o v o n H ö h enaufenthalten i n d e r S c h w a n g e r schaft Teratogenic Risk of High Altitude during Pregnancy
SUMMARY Early human development is an amazingly complex and perfectly regulated process. Essential nutrition- and oxygen-supply is provided by the placenta. High altitude is associated with a reduced oxygen partial pressure in maternal arterial blood and subsequently in the placenta. Hypoxia in the embryo and foetus has been shown to cause congenital anomalies and pregnancy complications, thus acting as a teratogen. In this article we present a short introduction into teratologic risk assessment and the principles of teratology, and summarize the current knowledge on the effect of high altitude on human pregnancy. Therefore we analyse the available data on placenta- and embryo-development under hypoxic conditions in animals and humans to provide a background (biologic plausibility!) for the evaluation of (rare) epidemiologic data on pregnancy at high altitude. Furthermore we discuss a possible evolutionary adaptation of human reproduction to high altitude. Studies on pregnancy outcome at high altitude in women from native altitude populations e.g. the Tibetans suggest pregnancy – protective characteristics to have evolved over thousands of years in these populations. This leads to a significantly reduced risk for adverse pregnancy outcome, compared to women with short altitude residency. Finally we try to deduce general recommendations on pregnancy at high altitude for (European) women, considering gestational age and additional factors possibly modifying the teratogenic risk of this exposure. Keywords: teratogenic risk, placenta, embryo, pregnancy, altitude, hypoxia
ZUSAMMENFASSUNG Die frühe menschliche Entwicklung im Mutterleib ist ein faszinierender, perfekt regulierter Prozess. Die Nährstoff- und Sauerstoffversorgung erfolgt über die Plazenta. Der Aufenthalt in großen Höhen führt über eine reduzierte Sauerstoffsättigung des mütter205
