For most pregnancies, flying is safe up to 36 weeks. If you have no complications, air travel poses no significant risk to you or your baby, and the second trimester is generally the most comfortable window to fly. That said, certain pregnancy conditions make flying inadvisable, and the further along you are, the more factors come into play.
The Safest Time to Fly
The second trimester, roughly weeks 14 through 27, is the sweet spot for air travel. The risks of common pregnancy emergencies are lowest during this period, morning sickness has typically eased, your energy levels are higher, and you’re not yet dealing with the discomfort and mobility challenges of the third trimester.
Flying remains safe through most of the third trimester, but after 36 weeks, most providers recommend staying close to home. At that point, the risk of going into labor on a plane becomes real enough that many airlines won’t let you board. If you’re carrying multiples, your provider may suggest an earlier cutoff since preterm labor is more common with twin and triplet pregnancies.
When Flying Is Not Recommended
Some pregnancy conditions make air travel genuinely risky. The CDC lists several absolute contraindications, meaning the potential harm always outweighs the benefits:
- Active labor or preterm labor
- Cervical insufficiency (a cervix that’s opening too early)
- Pre-eclampsia, current or past
- Placental abruption (the placenta separating from the uterine wall)
- Ruptured membranes (your water has broken)
- Vaginal bleeding
- Suspected or confirmed ectopic pregnancy
Other conditions fall into a gray area where flying may or may not be safe depending on severity. These include placenta previa (a low-lying placenta), fetal growth restriction, a history of miscarriage, and carrying multiples. If any of these apply, the decision involves weighing how necessary the trip is against your specific risk level.
Conditions worsened by low oxygen also deserve attention. Cabin air is pressurized to the equivalent of about 6,000 to 8,000 feet elevation, which slightly reduces the oxygen in your blood. For a healthy pregnancy, this is not a problem. But if you have sickle cell disease, severe anemia, certain cardiovascular conditions, or fetal growth restriction, that mild oxygen dip could cause complications.
Blood Clot Risk on Flights
Pregnancy already increases your risk of blood clots because your blood clots more readily (a natural adaptation to prevent excessive bleeding during delivery). Sitting still in a cramped airplane seat for hours compounds that risk. Long-haul flights are the primary concern, but even shorter flights warrant some precautions.
The simplest measures are also the most effective. Get up and walk the aisle every hour or two. While seated, flex and extend your ankles, rotate your feet, and shift your position regularly. Graduated compression stockings, the knee-high kind that are tighter at the ankle, help keep blood from pooling in your lower legs. Staying well hydrated matters too, since cabin air is extremely dry and dehydration thickens your blood. Skip the coffee on board and drink water consistently throughout the flight.
If you have additional risk factors for clots, such as a personal or family history of deep vein thrombosis, a clotting disorder, or a BMI over 30, talk to your provider before booking. They may recommend specific preventive steps beyond the basics.
Airport Security Scanners
The TSA states that all screening equipment at airport security checkpoints is safe for pregnant travelers. The full-body scanners used in most U.S. airports are millimeter-wave machines, which use low-energy radio waves rather than ionizing radiation. They pose no known risk to a developing baby. If you’d still rather skip the scanner, you can request a pat-down instead.
Airline Policies and Documentation
Airlines set their own rules about how late in pregnancy you can fly, and these vary. Many domestic carriers allow travel up to 36 weeks for uncomplicated single pregnancies, while international flights often have earlier cutoffs. Some airlines require a letter from your provider confirming your due date and that you’re cleared to fly, particularly in the third trimester. Others ask for proof of gestational age.
These policies aren’t always posted prominently, and they change. Call your airline directly before booking to confirm their requirements. Having a dated provider letter with your due date on hand is a good idea for any third-trimester flight, even if the airline doesn’t explicitly require one. Gate agents sometimes ask.
Practical Tips for Flying Comfortably
An aisle seat makes everything easier. You can get up to stretch and use the restroom without climbing over other passengers, which you’ll want to do frequently. The bulkhead row offers more legroom if you can get it.
Wear your seatbelt below your belly, across your hips and upper thighs, not over the bump. Keep it fastened whenever you’re seated, even when the seatbelt sign is off, since unexpected turbulence is the biggest physical risk to any passenger. Loose, breathable clothing and supportive shoes help with the swelling that cabin pressure and immobility can cause.
Cabin humidity hovers around 10 to 20 percent, far drier than most indoor environments. That dry air pulls moisture from your body faster than you’d expect, so drink water before, during, and after the flight. Bring an empty water bottle through security and fill it at the gate. Relying on the small cups the flight crew passes out won’t be enough on anything longer than a short hop.
If you’re flying internationally, check whether your destination requires any vaccinations or has health risks like Zika that could affect your pregnancy. Some travel vaccines are not safe during pregnancy, so this planning needs to happen well before departure.