If you have a normal, healthy pregnancy, it can be perfectly safe to fly during most of it. Discuss your trip plans with your doctor or midwife, however, before booking your flight. In certain high-risk cases, your healthcare provider may advise you to stay close to home throughout your pregnancy.
You may find that your second trimester — weeks 14 to 27 — is a perfect time to fly. Once you're past the first trimester, in all likelihood your morning sickness will be behind you, your energy levels will be higher, and your chances of miscarriage will be low. However, you shouldn't travel after 36 weeks.
Before you leave, have your prenatal caregiver refer you to an obstetrician or midwife at your destination in case you need medical attention during your vacation. If you'll be traveling during your second or third trimester, it's a good idea to carry a copy of your prenatal chart. The chart should include your age, the date of your last menstrual period, your due date, the number and outcomes of any prior pregnancies, your risk factors for disease, pregnancy-related lab tests and ultrasounds, medical and surgical history, and a flow sheet of vital signs taken at each visit.