Written by:

Dr Aarthi Mohan

BSc (Hon), MB BS, PhD, MRCOG, MRCP

Dr Mohan is a consultant obstetrician and specialist in maternal medicine in Bristol. She is experienced in both high and low risk pregnancy care, and looks after women with underlying medical conditions during their pregnancies. Aarthi graduated from Guy’s and St Thomas’ Hospital, London and went on to complete specialist training in obstetrics and gynaecology in London, as well obtaining a PhD from Imperial College, London, researching the causes of preterm labour. She has undergone training in general and specialist medicine, and has been invited to speak at a number of national and international conferences.

Air Travel in Pregnancy

In this article:

  • When is it safe to fly?
  • The first trimester (0-12 weeks)
  • The second (13-27 weeks) and third (28 weeks to delivery) trimesters
  • What should I take with me?
  • Am I at increased risk of problems if I travel by air?
  • Deep vein thrombosis (DVT)
  • Cosmic Radiation and Body scanners
  • Low oxygen saturation
  • Antimalarial prophylaxis and vaccinations
  • In Summary
  • Main points

Air Travel in Pregnancy

Air travel is a convenient and common form of transport, and is used by approximately two billion passengers worldwide each year. Many women have jobs involving flying frequently, and healthcare professionals are often asked questions regarding the safety of flying in pregnancy. There is no evidence that, if you have an otherwise uncomplicated pregnancy, air travel increases the risk of pregnancy complications.

If you have medical or pregnancy-related conditions that could be worsened by flying, or could need urgent obstetric care during the flight, you should avoid travelling by air. Each decision should be based on the individual pregnancy and circumstances of travel, including the length of flight, and it is advisable to inform and check with the individual airline carrier on every occasion when you are considering flying.

When is it safe to fly?

If your pregnancy is going well and is uncomplicated, most commercial airlines will allow you to fly up to 37 weeks of gestation for singleton pregnancies, and up to 33 weeks of gestation for uncomplicated twin pregnancies, however, after 28 weeks’ gestation, you should carry a letter from your GP or obstetrician confirming that your pregnancy is uncomplicated and specifying the estimated date of delivery. It may also be more difficult to get travel insurance after 37 weeks’ gestation.

The first trimester (0-12 weeks)

If you are at increased risk of a miscarriage of ectopic pregnancy, the location and viability of pregnancy should be confirmed by a hospital ultrasound scan before you travel. This would apply if you have had previous miscarriages or an ectopic pregnancy, or if you have had tubal surgery, a history of pelvic inflammatory disease, have become pregnant after sterilisation or whilst using an intrauterine contraceptive device (coil) amongst other conditions. If you are having any vaginal bleeding or abdominal pain, it is advised that you defer your travel until the symptoms have settled and an ultrasound scan has confirmed the location and viability of the pregnancy.

The second (13-27 weeks) and third (28 weeks to delivery) trimesters

The best time to travel by air is thought to be the second trimester of pregnancy, when pregnancy-related complications, including miscarriage, are less common. At any time in the pregnancy, if you are at risk of going into early labour, or have medical conditions which may be worsened by air travel, you should reconsider your travel options.

You should take into account the availability of hospitals at your travel destination, as facilities for managing premature infants may not be optimal. Other serious adverse pregnancy events, such as major bleeding in pregnancy and cord prolapse (when the umbilical cord comes out of the uterus before the baby is born), may be life threatening and difficult to predict, especially with lack of trained personnel and adequate facilities on board the aeroplane to deal with such emergencies.

What should I take with me?

The following list is a useful starting point for considering your pregnancy travel luggage needs:

  • Your medical hand-held notes
  • Any medication you are taking
  • If you are over 28 weeks pregnant, a letter from your doctor stating when your baby is due, confirming that you are in good health, are having an uncomplicated pregnancy and are not at increased risk of complications
  • Travel insurance documents
  • If you are travelling to Europe, it is recommended that you take a European Health Insurance Card (EHIC) with you. This is not an alternative to health insurance but lets you get free or reduced-cost health care in Europe. You do not have to pay for this and you can apply for it online www.nhs.uk/NHSEngland/Healthcareabroad/EHIC/Pages/about-the-ehic.aspx. It includes routine maternity care, as long as you are not going abroad to give birth. However, if the birth occurs unexpectedly, the card will cover the cost of all medical treatment for the mother and baby that are linked to the birth.

Am I at increased risk of problems if I travel by air?

Most pregnant women have no problems when flying, however, you may experience some discomfort, including swelling of your legs due to fluid retention or oedema. You may also have nasal congestion, as, during pregnancy, you are more likely to have a blocked nose, and combined with this, the changes in air pressure in the aeroplane can cause you to experience problems in your ears.

You should wear your seatbelt continuously while seated, as turbulence may be difficult to predict. The seatbelt should be belted low on the hipbones between the lower part of your abdomen and top of the thighs. The cabin crew will help you if you need a seatbelt extension.

Deep vein thrombosis (DVT)

A deep vein thrombosis is a blood clot which can form in your leg or pelvic veins. It causes pain and swelling in the leg and can travel up to the lungs (pulmonary embolism) and be life-threatening. When you are pregnant (and for the six weeks after the baby’s birth), you have a 10-fold higher risk of developing a clot compared to non-pregnant women. You are at increased risk of developing a clot if you fly whilst being pregnant. This is especially the case in long-haul flights of greater than four hours’ duration, when immobility, low humidity and dehydration play important roles.

It is recommended that you wear properly fitted graduated elastic compression stockings during flights lasting more than four hours. If you have additional risk factors for blood clots such as being overweight, are a smoker, are over 35 years of age, or have a condition which predisposes you to clot more readily (a thrombophilia), you may need to take blood thinning injections of low molecular weight heparin for the day of travel as well as for a number of days after the flight. This should be a decision made by your obstetrician, who will decide the duration of the injections based on an individual risk assessment after a full discussion of the risks and benefits with you.

  • maintaining good fluid intake by drinking lots of water during the flight
  • minimising caffeine and alcohol intake to avoid dehydration
  • taking regular walks around the cabin
  • carrying out in-seat exercises every 30 minutes on a medium or long-haul flight
  • having an aisle seat so you can easily move around the cabin

Cosmic Radiation and Body scanners

The increased cosmic (high energy) radiation associated with occasional air travel in pregnancy is not considered significant in terms of risk to the mother or baby. There is no known increase in miscarriage or fetal malformations or effects on growth at levels less than 50 millisieverts (mSv). The exposure from a 10-hour flight is estimated to be 0.05 mSv and the estimated cumulative background radiation per year in the UK is 2.2 mSv. The risk to the baby of a single period of air travel is, therefore, negligible; however, if you are a frequent flier, caution should be used.

Similarly, the total radiation from a body scanner used for security purposes in airports is less than that received from two minutes of flight, or from one hour at ground level. Negligible radiation doses are absorbed into the body and the fetal dose is much lower than the dose to a pregnant woman, and there are no data to suggest that you should avoid such security checks.

Low oxygen saturation

The World Health Organisation (WHO) advises pregnant women not to travel to altitudes over 3000m, because of the risk of hypobaric hypoxia, a condition where the body is deprived of a sufficient supply of oxygen from the air to supply to the body tissues. Travel to areas with altitudes up to 2500m is considered safe, however. Your heart rate and blood pressure may go up, in order to adapt to the relative reduction in oxygen breathed in, in aeroplane cabin environments. The baby is able to maintain higher oxygen saturations in this environment due to fetal haemoglobin having a greater affinity for oxygen than adult haemoglobin, which protects it during routine flight conditions. Pregnant women with serious pre-existing heart or lung disease, a recent sickle cell crisis, recent bleeding or with severe anaemia with a haemoglobin reading of less than 80 g/L, are strongly advised against air travel as they may not be able to tolerate the low oxygen environment. Additional oxygen should be considered if travel is absolutely necessary in these circumstances. Women with known mild to moderate anaemia (haemoglobin between 80 and 105 g/L) should aim to optimise their haemoglobin before they travel. There are other conditions where air travel may be strongly discouraged and each woman should be risk stratified and advice should be individualized.

Antimalarial prophylaxis and vaccinations

Antimalarial prophylaxis should be used if you are planning to travel to endemic areas and up to date advice regarding immunisations prior to travel must be sought. Vaccines which contain inactivated viruses, bacteria or toxoids are considered safe, however, live vaccines, such as yellow fever, should be avoided. During the recent Zika epidemic, it was advised that pregnant women should postpone non-essential travel to areas with active Zika transmission until after pregnancy, and that women should avoid becoming pregnant while travelling in an area with active Zika virus transmission, and for 8 weeks following returning home (whether they had symptoms of Zika infection or not).

In Summary

In summary, there is no evidence that air travel in pregnancy increases the risk of pregnancy complications, however, it is important to be individually risk assessed each time you travel. There is a small increase in the risk of venous thromboembolism, if your flight is more than four hours’ duration, but the absolute risk is still low.

Main points

  • There is no evidence that flying presents any risk to an uncomplicated pregnancy.
  • Women with health or pregnancy related conditions should consult a doctor before making any decision to fly.
  • In most cases you can fly up until 37 weeks of pregnancy, and up to 33 weeks for uncomplicated twin pregnancies. However, after 28 weeks, you should carry a letter from your GP or obstetrician detailing your health and estimated date of delivery.
  • It may be more difficult to get travel insurance after 37 weeks’ gestation.
  • The second trimester of pregnancy is usually thought of as the best time to fly. This is because pregnancy-related complications, including miscarriage, are less common in this phase.
  • Always consider the level of medical/pregnancy care available at your place of destination. Is it adequate to meet all possible scenarios?
  • Pack all your important pregnancy, health and travel insurance documentation.
  • Wear your seatbelt throughout your plane journey, as turbulence may be difficult to predict. The seatbelt should be belted low on the hipbones between the lower part of the abdomen and top of the thighs. Cabin crew can assist if you need a seatbelt extension.
  • You are at increased risk of developing a DVT (blood clot) if you fly when you are pregnant, especially if the flight lasts longer than four years.
  • Reduce the chances of a clot while flying by ensuring you are well hydrated and wear properly fitted graduated elastic compression stockings for flights lasting more than four hours.
  • Radiation levels from flying and scanners are minimal. However, if you are frequent flyer, you should exercise caution.