How safe is flying during early pregnancy (below 4 weeks)?

Safe: That should be fine. If a woman has sickle cell disease, clotting disorders or certain placental problems she should get advice of her obstetrician if she plans to fly.

Completely: Safe at that early time. Have fun!

Not very safe: Pregnant woman fly all he time with out thinking , possible adverse effects, most air lines will not allow after 36 wks ( 32 for multiple ) for fear of premature delivery, in first trimester , miscarriage, effects of ionic radiation at 30, 000 ft on fetus , resulting birth defects, common venous problems like phlebitis etc even pe , if you can avoid is not a good idea to fly at 4 wks pregnancy.