Radiation and pregnancy
I know that this is an old thread but I found it when searching for info about flying when pregnant. So just in case anyone else does the same here's some company information about cosmic radiation, flying and pregnancy.
Q: How much radiation will I be exposed to?
A: The International Commission on Radiological Protection (ICRP) recommends a maximum exposure from occupational sources of 20 mSv per year (averaged over a period of 5 years) with an additional recommendation that the equivalent dose to the foetus in pregnant women should not exceed 1 mSv during the declared term of the pregnancy. Occupational exposure for flight, cabin crew and duty travellers will depend on the route, altitude and aircraft type. On average, dose rates received will be in the order of:
• Long haul aircraft - 5 μSv (microsieverts) per hour;
• Short haul aircraft - 1-3 μSv (microsieverts) per hour dependent on the altitude reached.
In general, for crew members it is expected that:
• long-haul crew will have an annual exposure of approximately one fifth of the recommended dose
limit i.e. 4 mSv per year;
• short-haul crew will have an annual exposure of approximately one tenth of the recommended dose limit i.e. 2 mSv per year.
Q: What is the risk to me?
A: When ionising radiation passes through the body, energy is transmitted to the tissues which
affects the atoms within the individual cells. This may result in:
(i) Development of cancer.
A cell may be altered as a result of being irradiated and subsequently become cancerous.
The likelihood of this happening will depend on the dose received. For an accumulated
dose of 5 mSv per year over a career span of 20 years (more than the anticipated annual
exposure for long haul crew) the likelihood of developing cancer due to the radiation will
be 0.4%. This however needs to be put in perspective as 23% of the population will die
from some type of cancer so the overall risk will therefore increase from 23% to 23.4%.
Compared with all other risks encountered during the working life, this is very low.
(ii) Genetic risk.
A child conceived after exposure of the mother or father to ionising radiation is at risk of
inheriting radiation induced genetic defects. These may take the form of anatomical or
functional abnormalities apparent at birth or later in life. The risk following an
accumulated dose of 5 mSv per year over a career span of 20 years will be 1 in 1,000.
Again this needs to be considered against a background incidence in the general
population of approximately 1 in 50 for genetic abnormalities.
(iii) Risk to the health of the foetus.
With regard to pregnancy, the ANO requires airlines to reduce the dose received by the
foetus to a level ‘as low as reasonably achievable’. As a result, although the risks to the
foetus from cosmic radiation are insignificant when compared with the other risks during
pregnancy, all female flight and cabin crew in this airline will be assigned to ground
duties on declaration of pregnancy. Duty travellers will need to make their own risk
assessment taking into account the likely exposure and resultant risk.
The possible effects of radiation to the foetus are cancer and mental retardation. There is of
course a background rate for both of these conditions and it is estimated that exposure to cosmic
radiation for 80 block hours per month for a period of 4 weeks will increase the risk by between 1
in 6,000 and 1 in 30,000 depending on the routes flown. Many crew members will be aware that
they are pregnant within a very few weeks and the real risks will therefore be proportionately less.
Q: Has this airline looked at the effects in crew?
A: As well as working with the scientific community on the measurement of cosmic radiation,
this airline has undertaken epidemiological studies examining the causes of death and life
expectancy of flight crew over the last 40 years.
It has been found that pilots and flight engineers have an increased life expectancy of between 3
and 5 years compared to the general population. Mortality from heart disease and all cancers
combined is considerably less in flight crew than for the population of England and Wales as a
whole and, although rare, death from melanoma (which is associated with exposure to sunlight)
was the only cause of cancer in excess. The mortality from cancer such as leukaemia, which may
be linked to radiation exposure, was lower than for the general population.
Further larger studies are continuing to which this airline is contributing and as a result,
more information will be available in due course.
29 - 4
Q: What is this airline doing about cosmic radiation?
A: Under the ANO, the cosmic radiation dose received by flight, cabin crew and duty travellers
will be considered as occupational and therefore the dosage experienced by all crew will be
monitored. As a result, all major European carriers will be estimating doses for each sector using a sophisticated computer model which takes into account
all the factors previously discussed including the aircraft climb and descent profiles, latitude of
the flight, altitude, time of year and point in the solar cycle. The computer estimates will be
periodically validated by measurements performed in flight.
Q: How do I find out what dose I have received?
A: All staff can obtain a record of their radiation exposure through the company Intranet. This record includes rostered duties for flight and cabin crew.
Q: Is there anything more I should be doing?
A: At this stage no.
Conclusion
Cosmic radiation is both a complex and emotive subject. It cannot be seen, touched,
smelt or tasted and yet it is present all around us. Whilst we know that there is no level of
radiation exposure below which effects do not occur, we can estimate the probability of
any harm occurring based on the exposure received. This, coupled with the knowledge of
doses received by crew in this airline and the available epidemiological studies,
reassures us that there is an extremely low probability of staff suffering an abnormality or
disease as a result of occupational exposure to cosmic radiation.