ACOG Committee Opinion No. 746: Air Travel During Pregnancy.

In the absence of obstetric or medical complications, occasional air travel is safe for pregnant women. Pregnant women can fly safely, observing the same precautions for air travel as the general population. Because severe air turbulence cannot be predicted and the subsequent risk for trauma is significant should this occur, pregnant women should be instructed to use their seat belts continuously while seated. Despite a lack of evidence associating lower extremity edema and venous thrombotic events with air travel during pregnancy, certain preventive measures can be used to minimize these risks, including use of support stockings and periodic movement of the lower extremities, avoidance of restrictive clothing, occasional ambulation, and maintenance of adequate hydration. For most air travelers, the risks to the fetus from exposure to cosmic radiation are negligible. However, aircrew or frequent flyers may exceed these limits. The Federal Aviation Administration and the International Commission on Radiological Protection consider aircrew to be occupationally exposed to ionizing radiation and recommend that they be informed about radiation exposure and health risks.