Radiation

Pregnancy and flying: what the radiation numbers mean

October 20, 20267 min readFor pilots and passengers

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In this article

What a flight adds
The limits once a pregnancy is declared
What a crew month looks like
What the studies of flight attendants found
Solar storms
For passengers
What crew members can do
Seeing your own dose in LogAloft

Most questions about pregnancy and flying come down to two numbers. One is how much cosmic radiation a flight adds, and the other is how much is considered acceptable for an unborn child. For a passenger taking a few trips, the first number is very small next to the second. For a crew member flying a full schedule, the two get close enough over a pregnancy that it is worth knowing both. Here is what the guidance says, what the studies of flight attendants found, and how to follow your own dose.

What a flight adds

Cosmic radiation at cruise depends on time aloft, altitude, latitude and the state of the Sun, the four factors the FAA lists in AC 120-61B. Under the solar conditions of July 2026, LogAloft's model gives these doses for some common flights (the full list is in How much radiation do you get on a flight?):

Flight	Air time	Dose	Share of a chest X-ray
Atlanta–Orlando	1.2 h	0.002 mSv	2%
Los Angeles–New York	5.0 h	0.019 mSv	19%
New York–London	6.8 h	0.030 mSv	30%
New York–Tokyo	13.5 h	0.065 mSv	65%

For the last column, a chest X-ray means a standard two-view exam at 0.1 mSv, as listed in the catalog by Mettler and colleagues. Fly the North Atlantic both ways and you get about 0.06 mSv.

The limits once a pregnancy is declared

Three bodies set the reference points, and they line up closely.

The International Commission on Radiological Protection (ICRP) sets the framework most countries follow. Its 2007 recommendations, Publication 103, say that once an employer has been told of a pregnancy, the pregnant worker's conditions should ensure the additional dose to the embryo or fetus "would not exceed about 1 mSv during the remainder of the pregnancy." That is the same figure as the ICRP's yearly limit for members of the public.

The European Union makes it law. Council Directive 2013/59/Euratom, Article 10(1), requires that as soon as a pregnant worker informs the employer, her working conditions keep the equivalent dose to the unborn child "as low as reasonably achievable and unlikely to exceed 1 mSv during at least the remainder of the pregnancy." Article 35(3)(d) applies that rule to pregnant aircrew at airlines whose crew doses are liable to exceed 1 mSv a year.

The FAA gives guidance, with no binding limit. AC 120-61B, paragraph 7c, says that in addition to the normal occupational limits, "the FAA recommends she limit ionizing radiation exposure of her conceptus to no more than 0.5 mSv per month." No US regulation requires an airline to track or cap a crew member's dose, pregnant or not.

Source	Limit for the unborn child	Status
ICRP 103	About 1 mSv for the rest of the pregnancy, once declared	Recommendation
EU Directive 2013/59/Euratom, Art. 10	Unlikely to exceed 1 mSv for at least the rest of the pregnancy	Law in EU member states
FAA AC 120-61B, para. 7c	No more than 0.5 mSv in any month	US guidance

The FAA circular also makes a point worth keeping in mind for any of these numbers. Its recommended limits, it says in paragraph 7b, "are not thresholds beyond which the dose is intolerable but instead are upper limits of acceptability." Crossing one is a reason to change the schedule. It is not a sign that harm has occurred.

What a crew month looks like

A crew member's dose builds hour by hour. On North Atlantic or transpacific routes at today's solar activity, a typical rate at cruise is about 4 µSv an hour. At 75 block hours a month that is about 0.3 mSv a month, inside the FAA's monthly figure but enough to reach 1 mSv in a little over three months. The same hours on low-latitude flying, at about 2 µSv an hour, come to about 0.15 mSv a month.

So the monthly figure is rarely the one that binds. Over a whole pregnancy the 1 mSv total matters more, and a crew member who keeps flying long-haul high-latitude trips would pass it partway through. This is why the EU rule starts when the worker informs the employer, and why telling the airline early gives it more room to adjust your flying.

What the studies of flight attendants found

The largest study is from the National Institute for Occupational Safety and Health (NIOSH). Grajewski and colleagues (2015) interviewed flight attendants and teachers from three US cities and built each flight attendant's exposures from company records of about 2 million flights. A flight attendant with the median exposures for the first trimester flew 130 hours in 53 segments and received about 0.36 mSv.

Their results, briefly:

Compared with teachers, flight attendants had no higher risk of miscarriage.
Flying through home-base sleep hours (15 hours or more between 22:00 and 08:00 home time in the first trimester) went with a higher risk of first-trimester miscarriage, an odds ratio of 1.5.
High physical job demands, such as standing and walking more than 8 hours a day, went with a higher risk too (odds ratio 2.5).
Cosmic radiation of 0.1 mGy or more "may be associated" with miscarriage in weeks 9 to 13, with an odds ratio of 1.7 and a confidence interval of 0.95 to 3.2. That range includes no effect at all, and the authors note that the radiation and sleep-disruption measures were hard to separate, because the same flights carried both.

An earlier Italian survey by Lauria and colleagues (2006) found similar miscarriage rates for pregnancies while in service and out of it, 12.6% and 11.4%.

Taken plainly, the studies point at the whole job, night flying and physical work included, more than at radiation alone. They are also a reason to treat the limits above as sensible planning numbers.

Solar storms

The doses above are for ordinary galactic cosmic radiation. A strong solar particle event can add to it, mostly on polar and high-latitude routes. In the NIOSH study about 2% of pregnancies were likely exposed to one, and on one of the flights studied the dose from a single event reached about 0.45 mGy, according to the NIOSH announcement. Such events are rare, and AC 120-61B notes that descending to a lower altitude during a solar radiation alert can cut the dose a good deal at high latitude. Solar storms and your flight explains the alerts and what they mean on board.

For passengers

The American College of Obstetricians and Gynecologists says in Committee Opinion 746 that, without obstetric or medical complications, occasional air travel is safe in pregnancy, and that for most air travelers the risks to the fetus from cosmic radiation are negligible. It adds that aircrew and frequent flyers may exceed the limits.

In numbers, a pregnant passenger who takes three round trips between New York and London receives about 0.18 mSv, under a fifth of the 1 mSv reference for the whole pregnancy. The same opinion advises keeping the seat belt fastened whenever seated, because turbulence can't be predicted. If you fly very often while pregnant, ask your obstetrician, who can weigh the trips together with everything else about your pregnancy.

What crew members can do

Tell your airline early if you want the protections that come with a declared pregnancy. In the EU the employer's duty starts when you inform it.
Ask what your company offers. Policies on reassignment, lower-dose flying and leave differ by airline and by contract.
Look at the trips before you bid. Two pairings in the same month can differ a lot in dose. Latitude and time at cruise are the levers.
Talk to your doctor or your airline's medical department. They can put the radiation numbers next to the other parts of the job, such as night work and lifting, that the NIOSH study flagged.

Seeing your own dose in LogAloft

LogAloft works out the dose of every flight in your logbook. In Settings, under Pregnancy and your own levels, turn on Track my dose during a pregnancy and enter the day you told your airline, or the start of the pregnancy. The app then compares your dose since that day with 1 mSv for the rest of the pregnancy and 0.5 mSv in any month, or with limits you enter, and shows this month's total beside the pregnancy total. Reports → Radiation, with the period set from that date, gives the full record by month to print for your doctor or your airline.

The date stays on your device and isn't stored in your account. LogAloft compares your effective dose with these limits; the dose to the unborn child itself isn't calculated separately. The numbers are for planning and are not medical advice. How LogAloft works out your dose has the details.

For how the dose of each flight is worked out, see How LogAloft works out your radiation dose.

Sources

This is information, not medical advice. For questions about your own health or a pregnancy, talk to your doctor or aviation medical examiner.