**7. Conclusion**

Travel thrombosis in connection with long-haul flights (>4 h flight time) are rare (about 1/4500 passengers) and mostly affect the deep veins of the calf muscles. The proportion of pulmonary embolisms is significantly higher for female passengers than for male passengers (flight duration > 12 h: 4.8–7.2/1 million). The risk of venous thromboembolism depends primarily on the duration of the flight, the number of flights within 4 weeks, and individual thrombogenic risk factors. As a result of hypercoagulability and venous stasis, the risk for pregnant women is increased, and it is estimated at 0.03–0.1%. Long-term immobilization is the most important predisposing factor; the importance of hypobaric hypoxia and dehydration is controversial.

Before starting the flight, especially pregnant women are advised to carefully assess their risks. To reduce risk, in addition to general measures (e.g., physical activity), wearing graded, well-fitting compression stockings is recommended and if there is a high individual risk (e.g., previous VTE), prophylaxis administration of low molecular weight heparin before and immediately after the flight.
