Obstetrics and flying

• bleeding or pain during the first trimester - any symptoms that may suggest miscarriage or ectopic pregnancy are contraindications to air travel
• gestation
  • in general, airlines allow air travel until 36 weeks of gestation - however, flying is advised against after 32 weeks of pregnancy (1)
    • many airlines restrict travel beyond the end of the 36th week, or 32nd week for twins and other multiple births (1)

Notes:

• these are only guidelines, and each airline has its own regulations and medical standards
• there have been no case reports that have shown harm to the fetus if the mother travels briefly to high altitude during pregnancy; however, most authorities recommend pregnant women stay below 12,000 feet (3,658 metres)
  • there is no evidence that either chronic exposure in commercial aircraft or living at 10,170 feet (3100 metres) causes significant pregnancy-related problems (3)
• a pregnant traveller should be advised to know her blood type and ensure that she has valid travel insurance and that the policy covers a newborn should delivery take place
• because air travel can cause motion sickness, the practitioner should advise the pregnant traveller that the nausea and vomiting that occasionally occur in early pregnancy may be increased during flight (3)
• NICE stated previously that (2):
  • pregnant women should be informed that long-haul air travel is associated with an increased risk of venous thrombosis, although whether or not there is additional risk during pregnancy is unclear; in the general population, wearing correctly fitted compression stockings is effective at reducing the risk
• commercial aircraft environment is not generally considered hazardous to the normal pregnancy; at a normal cabin altitude, the maternal haemoglobin remains 90% saturated, and because of the favourable properties of foetal haemoglobin (HbF), including increased oxygen carrying potential plus increased fetal hematocrit and the Bohr effect, fetal PaO₂ changes very little (4)
  • the key focus in assessment of fitness to fly is the health and well-being of the mother and the baby; delivery in flight, or diversion in flight to a location that may not have high-quality obstetric services, is undesirable; for this reason, most airlines do not allow travel after 36 weeks for a single pregnancy and after 32 weeks for multiple pregnancies
  • most airlines require a certificate after 28 weeks, confirming that the pregnancy is progressing normally, that there are no complications and that the expected date of delivery
    • in specific individual circumstances, an airline may allow some discretion
• the IATA manual notes:
  • complicated pregnancies - acceptance to fly requires assessment on an individual basis*
    • miscarriage (threatened or complete) - may be accepted to fly once stable, no bleeding and no pain for at least 24 hours*
  • *are provided as a guide to the timeframe that should elapse between a medical event and the intended flight
    • Timeframes may be changed following considered medical assessment of a specific case
    • quality of care at the departing and arrival station is also a factor in the decision-making process

References:

1. Doctor (April 2005). Ready Reckoner - Fitness to fly.
2. NICE (March 2008). Antenatal care.
3. 'Medical Guidelines for Airline Travel, 2nd ed', Aviation, Space and Environmental Medicine, October 2003, 74 (5): II A1-A18.
4. Civil Aviation Authority. Fitness to Fly (Accessed 23/12/23).
5. International Air Transport Association (IATA). Medical Manual 11th Edition (2018).