Clinical Practice Guideline



Developed for the

Aerospace Medical Association

by their constituent organization

American Society of Aerospace Medicine Specialists


Overview: Pregnancy is a physiological state not a disease.  The associated alterations in anatomy and physiology warrant aeromedical attention due to an increasing number of female aviators, most of whom are in their reproductive years.  The diagnosis of pregnancy is made through serum laboratory testing.  Dating of the pregnancy is calculated in reference to the woman’s last menstrual period and ultrasound, if necessary.


Aeromedical Concerns: The aeromedical concerns can be considered in two separate categories: effects of pregnancy on the ability to perform in-flight duties and effects of the aviation environment on the fetus.  This includes: 1) danger of incapacitation, especially during the first trimester, due to spontaneous abortion, ectopic pregnancy, nausea and vomiting, or other complications, 2) weight gain, unsteadiness, and a risk of premature labor during the third trimester, and 3) potential effects of hypoxia, decompression sickness, and radiation on the fetus.  Although extreme hypoxia is obviously detrimental to the fetus, the oxygen saturation of fetal hemoglobin decreases less precipitously than maternal hemoglobin.  Radiation exposure at very high altitude or in space flight poses the risk of congenital malformation and developmental abnormality.


The Federal Aviation Administration (FAA) considers aircrews to be occupationally exposed to ionizing radiation, primarily from galactic cosmic radiation.  Although the United States currently has no regulations limiting aircrew exposure to cosmic radiation, the FAA has recommended limits.  For pregnant crewmembers, starting when the pregnancy is reported to management, the FAA recommends: a) a limit of 1 millisievert to the conceptus for the remainder of the pregnancy and b) a monthly limit of 0.5 millisievert to the conceptus.


To evaluate compliance with the recommended radiation limits, the appropriate version of the CARI (Civil Aeromedical Research Institute) computer program can be used to calculate the dose received on individual flights.  Because the mother’s body provides no significant shielding for the conceptus from galactic radiation, the dose to the mother is a good estimate of the dose to the conceptus.


CARI-6 (1) calculates the dose of galactic radiation received on an aircraft flying a great circle route (or a reasonable approximation) between any two airports in the world.  For flights that do not fly approximate great circle routes between airports, CARI-6M (2) can be used to estimate the dose.


It is highly recommended that a pregnant crewmember promptly report her pregnancy to her manager so that the employee and management can cooperate in ensuring that exposure of the conceptus does not exceed recommended radiation limits.  However, a crewmember’s disclosure of her pregnancy is voluntary and, under U.S. law (3), an employer cannot limit, classify, or segregate an employee or an applicant for employment in any way which would deprive or tend to deprive them of employment opportunities or otherwise affect the status of an employee because of or on the basis of pregnancy.


Pregnant crewmembers can minimize occupational exposure to galactic radiation by working on short, low-altitude, low-latitude flights


Regarding major U.S. airlines, American has prepared a training booklet on radiation exposure for its employees and Delta has expressed interest in a computerized system to estimate flight doses on all its routes.  As for direct training, we are only aware of the Cabin Safety Workshops held at CAMI.  American Airlines is planning to host a workshop on cosmic radiation exposure of flight personnel.  It will be open to all interested persons.


Some or all of the European airlines ground pregnant employees.  They take the radiation dose limits quite seriously.  Many use the CARI program to estimate flight doses.


Medical Work-up: Diagnosis of pregnancy made in usual fashion and this information is shared in a timely manner with the aeromedical authorities.


Aeromedical Disposition (military): Trained military aviators may be eligible for consideration for continued flying for uncomplicated pregnancy.  This eligibility is dependent upon 1) a voluntary request initiated by the aviator and 2) concurrence with this request by the aviator’s obstetrician.  Flying is restricted to pressurized multi-crew, multi-engine, non-ejection seat aircraft.  The waiver is valid for uncomplicated pregnancies from the 13th through the 24th week of gestation.


Aeromedical Disposition (civilian): The determination for temporary disqualification in pregnant aviators is dependent on the country, on the aircraft type, the type of aviation operation, and the nature of the duties on the aircraft.


Waiver Experience (military): Military waivers are normally approved at the local level as directed by the major command.


Waiver Experience (civilian): The United States civil aviation medicine authorities recommend that a woman not pilot an aircraft in the third trimester.  The obstetrician should be made aware of the aviation activities so they can best advise the airman.  The decision of the proper time for temporary grounding is normally left up to the individual airline and/or to the applicable national standards.




Lyons T. Women in the military cockpit. Occupational and Environmental Health Directorate, June 91; AL-TR-1991-0062: 23-26.


Office of Aviation Medicine, FAA.. Guide for Aviation Medical Examiners, October 1999, pg. 55.


CARI-6 computer program can be downloaded free of charge from Civil Aeromedical Institute Web site:


Rayman RB. Clinical Aviation Medicine, Third Edition, New York, Castle Connolly Graduate Medical Publishing, LLC, 2000:279-81.


United States Code, 42 USC Sec.2000e-2, (42 USC 2000e-2(a), “Employer practices”, it is unlawful to discriminate because of sex.  42 USC 2000e(k), “Definitions”, the terms “because of sex” or “on the basis of sex” include because of or on the basis of pregnancy.) 



October 9, 2001