This review describes adverse outcomes in pregnancy after brief, intermittent, or permanent residence at high altitudes. Review of literature shows that congenital malformations rates are higher at high altitudes. Additionally, rates of stillbirths, small size for gestational age, and preeclampsia are increased in populations living at high altitudes and are associated with high maternal hemoglobin levels (>14.5 g/dl). In conclusion, a pregnant woman exposed briefly, intermittently, or permanently to high altitudes results in increased risk of adverse outcomes when compared to pregnancies observed at sea level.