common gynaecological disorders and their likely effect on fitness to fly

In 1784 Mm Elizabeth Thible ascended over Lyon, France in a Montgolfier balloon probably aware of the generally held view of the day, and in many respects a view still held today, that aviation was a male preserve. As the art and science of aviation evolved many of the pioneering female aviation achievements have been met with scepticism, scorn, and ridicule. Men have invented many reasons, often reflecting an ignorance of female anatomy, physiology, and psychology to preclude women from a more active participation in aviation. Even today there is much myth and male dominated 'reasoning' to prevent women from a more active role in military aviation. Thankfully even this last bastion of male dominance in aviation is now crumbling as evidenced by the NATO forces having in excess of 1000 female military pilots and permitting some of them to fly active combat missions.

Despite being different to men in many respects there is no intersex difference that makes women inherently less able to participate in aviation pursuits than men. There are medical conditions peculiar to women that may make them temporarily or permanently unfit to fly and as with men there are features of some women that may make them more or less suited to particular roles within the aviation industry. None of these reasons however make the female of our species innately unsuitable to aviate.

This essay introduces some of the physiological and pathological conditions that are unique to women and discusses their potential effect on 'fitness to fly'. Fitness to fly, herein, refers to aircrew duties primarily as a pilot but may also apply to navigators, flight engineers, and other occupations peculiar to the military such as loadmasters and electronics operators. Fitness to fly in this essay does not intend to include flying positions such as cabin attendant, stewards, or passengers. In general terms a 'condition' is likely to render a woman unfit to fly if there is a significant risk of:

  • Sudden incapacitation especially due to severe pain or the collapse of an essential organ system;
  • Annoyance, disturbance, or distraction sufficient to interfere with the safe conduct of flight responsibilities;
  • Restriction of free movement or the use of equipment based on normal ergonomic design;
  • Dangerously altered mental function;
  • Inconvenience resulting in reduced effectiveness in flight.
  • Factors such as smaller average size (true), less strength on average (true), less intelligence for technical matters (false), different personality make-up (debatable), potential distraction of male colleagues (true), reduced innate flying ability (false), and emotional liability (debatable) have all been proposed at one time or another (by males I suspect) as reasons to exclude women from aviation. While smaller size and less strength may make it difficult for some women to perform some of the more physically demanding aircrew duties this will gradually be overcome with time as ergonomic designs sympathetic to women as well as men evolve. A number of studies have dismissed the myths that women are inferior to men in aviation related cognitive and psychomotor functions. While it can be argued that women react to stress differently to men it could also be argued that in general a woman's reaction is more productive than that of a man. While women may, in general, have different personality traits to men there is no reason that this should preclude them from aviation. Similarly many armed forces around the world have exploded (often literally) the myth that the female psyche is unsuitable for active combat roles. While no-one would argue that a woman, especially an attractive woman, is a potential distraction for a male colleague it is bizarre that this reason has been seriously touted as sufficient excuse to exclude women from flight deck duties.

    The medical and physiological conditions that will be discussed are listed below. Between them this list would probably make up 99% of a routine gynaecological practice.

  • Hereditary Disorders:
  • Absence or duplication of organs;
  • Imperforate hymen.
  • Fertility and Infertility
  • Contraception; Infertility.
  • Menstruation and menstrual disorders:
  • Normal menstruation;
  • Mittelshmerz:
  • Premenstrual Tension;
  • Dysmenorrhoea, Amenorrhoea, Menorrhagia, etc.;
  • Dysfunctional Uterine Bleeding;
  • Endometriosis;
  • Adenomyosis uteri.
  • Pregnancy and it's Interruption:
  • Normal pregnancy;
  • Abortion;
  • Ectopic Pregnancy;
  • Tumours of the trophoblast.
  • Infections:
  • Bartholinitis:
  • Vaginitis; Cervicitis;
  • Pelvic Inflammatory Disease.
  • f Venereal Disease:
  • Gonorrhoea;
  • Non-specific Urethritis;
  • Syphilis; Herpes Simplex;
  • Genital Warts; HIV / AIDS.
  • Displacement of organs:
  • Uterine retroversion and
  • retroflexion; Uterine prolapse,
  • cystocoele, and rectocoele;
  • Stress incontinence.
  • h. Tumours:
  • Polyps;
  • Uterine Myomas;
  • Ovarian, Cervical, Endometrial, Vaginal, Uterine Tube, and Vulval Carcinomata.
  • Gynaecological hereditary disorders such as absence or duplication of organs or an imperforate hymen are not common. A congenital duplication or absence of parts of the female genital tract does not, in itself, render the woman unsuitable for aviation. Associated anomalies of the renal tract may lead to difficult to control urinary incontinence which may limit the depth of aviation open to a woman (vice infra). An imperforate hymen is virtually always identified and remedied prior to a woman attaining sufficient age to fly professionally, or for pleasure. The presence of a gynaecological hereditary anomaly should not, as a rule, preclude women from flying and each case should be individually assessed to determine whether the condition is likely to 'interfere with the safe exercise of licence and rating privileges' .

    The fact that a woman is infertile, in the absence of other problems, should have no effect what-so-ever on her 'fitness to fly'. Hormonal treatments for infertility may prompt review of a woman's flying status if the medication results in mood or personality changes. These rare cases should be reviewed on an individual basis.

    The use of the oral contraceptive pill (OCP) has been associated with an increase in the incidence of vascular thrombosis, thrombo-embolism, cerebrovascular accident, hepatic adenomata, biliary disease, and hypertension. The risk of the vascular complications is heightened if the woman taking the pill is also a smoker. OCPs may also cause personality, mood, and weight changes in certain susceptible individuals. Agents within an OCP may also interact with other medications. While I do not have available any statistics on the incidence of vascular complications amongst female aircrew I expect that they may be slightly increased in those taking OCP medication but I also expect that this slight increase would be overshadowed by the risk of smoking related problems. It is my opinion that in the absence of adverse effects or reactions the use of OCP medication should in no way stop a woman from flying. As with female mountaineers I would, however, attempt to educate female pilots concerning the vascular risks of oral contraception and strongly advise the cessation of smoking in any that are so addicted. Women who have suffered adverse effects from OCPs should be assessed on an individual basis. Although I can find no research data to support me I find it difficult to imagine how any other form of contraception, in the absence of complications, could possibly interfere with a woman's fitness to fly (except perhaps the withdrawal method if practised during flight).

    The normal, cyclical, menstrual period should, in no way, impair a woman's fitness to fly. While ill informed 'back-bar' conversation amongst, usually inebriated, male military aircrew occasionally broaches the potential effects of high-G on women wearing a tampon or sanitary napkin there is no evidence of any such unhygienic consequences of women flying during their period.

    There is, however, potential for an abnormal or complicated menstrual history to alter a woman's fitness to fly. While most cases of premenstrual tension are mild the occasional woman finds this syndrome debilitating. Severe premenstrual tension may be associated with aches and pains in the lower abdomen, back, and breasts, headaches, weight gain, and personality or mood changes. Any of these symptoms may make a woman unfit to fly during the premenstrual period. Such severe symptoms, if unresponsive to treatment and if likely to interfere with the safe conduct of flying tasks, should probably make a woman either temporarily or permanently unfit to fly. A woman whose symptoms are well defined and predictable and who is responsible and intelligent could justly argue that she should not be permanently precluded from flying as she is able to voluntarily ground herself during the premenstrual time period. I would seriously consider supporting this logic in the case of a civil private licence but suggest that the (often) lack of flexibility in commercial or military flying may make her unfit for these duties.

    Most women who suffer the mid-cycle pains of 'mittelshmerz' find the problem of nuisance value only. Occasionally the pain can be more severe leading to regular monthly bouts of incapacitation. I would apply similar logic to the case of mittelshmerz as for premenstrual tension and assess each case individually.

    Similarly dysmenorrhoea, amenorrhoea, menorrhagia, and dysfunctional uterine bleeding should all be assessed on their individual merits against the guide 'likely to interfere with the safe exercise of licence and rating privileges'. Dysmenorrhoea, or pain with menstruation, may be mild, moderate, or severe and either responsive to treatment or not. Mild or moderate dysmenorrhoea, especially if responsive to treatment need not interfere with a woman's flying status. Severe dysmenorrhoea should be considered on an individual basis and may be adequate cause for advising a woman as unfit to fly. Amenorrhoea, in itself, is not due cause for disqualification although the commonest cause of amenorrhoea, pregnancy, may well be (vide infra). The severity of menorrhagia will determine whether an individual should be disqualified from flying. It is difficult to imagine a woman wishing to fly while afflicted with severe menorrhagia. Similarly dysfunctional uterine bleeding, diagnosed only after the exclusion of other non-endocrine pathology will need to be assessed on individual merit.

    Endometriosis may be a severe and incapacitating disorder causing a woman to be unquestionably unfit to fly. This disqualification may need to be reconsidered should the endometriosis respond well to hormone therapy or ablative surgical procedures. This disease presents an element of uncertainty in that mild endometriosis may progress to severe symptoms without warning and treated cases may similarly erupt without notice. While each case needs to be considered individually I would probably err on the side of conservatism, and disqualification, with the unpredictable and potentially incapacitating endometriosis. Adenomyosis uteri, with ectopic endometrial tissue with the muscular wall of the uterus, should probably be afforded the same consideration as endometriosis.

    While pregnancy is certainly not a gynaecological disorder it is an event peculiar to women and carries with it the risk of impaired ability to perform flying duties. The physiological changes of pregnancy that may interfere with the safe operation of an aircraft include:

    • Nausea and vomiting of early pregnancy occur in 30% of all pregnancies, and can cause dehydration and malnutrition;

    • Approximately 15% of embryos will abort in the first trimester;

    • Cardiac output rises in early pregnancy, accompanied by an increase in stroke volume, heart rate, and plasma volume;

    • Haemoglobin, and haematocrit, begin to fall between the third and fifth month and is lowest by the eight month of pregnancy;

    • Adequate diet and supplementary iron and folic acid are necessary, but self medication and prescribed medication should be avoided;

    • The incidence of venous varicosities is three times higher in females than in males and venous thrombosis and pulmonary embolism are among the most common serious vascular diseases occurring during pregnancy;

    • As the uterus enlarges, it compresses and obstructs the flow through the vena cava;

    • Progressive growth of the foetus, placenta, uterus, and breasts, and the vasculature of these organs, leads to an increased oxygen demand;

    • Increased blood volume and oxygen demands produce a progressive increase in workload on both the heart and lungs;

    • Hormonal changes affect pulmonary function by lowering the threshold of the respiratory centre to carbon dioxide, thereby influencing the respiratory rate;

    • In order to overcome pressure on the diaphragm, the increased effort of breathing and hyperventilation leads to greater consciousness of breathing and possible greater cost in oxygen consumption;

  • The effects of hypoxia at increased altitude further increases the ventilation required to provide for increasing demands for oxygen in all tissues.

  • The first trimester of pregnancy exposes a woman to the risk of early spontaneous abortion, emesis or hyperemesis gravidarum, and the cardiovascular alterations mentioned above. Ectopic Pregnancy may also present during this time period. Each of these conditions has potential to cause sudden incapacitation in a female pilot and are of sufficient frequency to cause, in my opinion, a woman in the first trimester of pregnancy to be unfit to fly.

    Pregnancy's third trimester involves substantial somatic changes, most noticeably abdominal enlargement. The third trimester also carries the risks of premature labour and delivery as well as toxaemia of pregnancy. The combination of these factors causes me to believe that a woman pregnant in her third trimester is also unfit to fly.

    The second trimester of pregnancy has a relatively low risk of complication although the physiological changes outlined above continue. Late spontaneous abortion is probably the most dramatic, albeit rare, complication of the second trimester. While it can be well argued that a woman is fit to fly during the second trimester  I believe that risks and the possible uncertainty of dates do not warrant rescinding her disqualification during this middle two or three months of a pregnancy. I think that a woman should be disqualified from flight while pregnant and that her flying status should only be returned after a medical examination subsequent to the conclusion, successful or otherwise, of her pregnancy.

    A separate but related consideration is that of the incidence of foetal damage or spontaneous abortion induced by the flight environment. A first trimester foetus undergoes much of the organogenesis and differentiation that is so sensitive to external noxious influences such as radiation and chemical toxins. T here is the theoretical potential for the rigours of the flight environment to cause an increased incidence of foetal malformations or spontaneous abortions in pregnant female aircrew. The limited research available tends to consider air-hostesses rather than female pilots and does not seem to support the hypothesis of an increase in abnormal pregnancy outcomes  Air hostesses do suffer an increase in spontaneous abortion when compared to other women but not when compared to other working women. There is an increased incidence of past spontaneous abortion amongst pregnant air-hostesses  but this may be due to a selection bias where a previous successful pregnancy selects an individual out of the test population.

    To have a tumour of the trophoblast a woman would need to be pregnant and hence I would deem her unfit for flying duties. Malignant sequelae to trophoblastic tumours will be considered with other carcinomas later.

    Gynaecological infections such as bartholinitis, vaginitis, cervicitis, and pelvic inflammatory disease need not necessarily exclude a woman from flying. The discomfort associated with each of the above may cause temporary self suspension from flight or similar advice from a DAME should he/she be consulted. Once adequately treated none of these conditions should disqualify a woman from flight duties. Severe, uncontrolled pelvic inflammatory disease may cause sufficient incapacity to prompt a long term or permanent disqualification from flying on medical grounds.

    Women suffering venereal diseases such as gonorrhoea, non-specific urethritis, syphilis, herpes simplex, genital warts, and HIV / AIDS should all be assessed for fitness to fly on their individual merit and the likely history of the disease in question. It is unlikely that gonorrhoea, nonspecific urethritis or primary syphilis would necessarily ground a woman. The now very rare secondary or later sequelae of spirochaetal infection may be sufficient ground for disqualification due to the incidence of neurological and other systemic complications. Unless they cause great discomfort genital warts or genital herpes infections are an unlikely cause for disqualification. On the other hand I feel that the possibility of unpredictable neurological AIDS should preclude all HIV positive individuals, male or female, from aircrew status. I believe this should apply to all aircrew, not just pilots and navigators. Any aviator that presents with any venereal disease should also have their HIV status determined

    Gynaecological organ displacement problems such as uterine retroversion and retroflexion, uterine prolapse, cystocoele, and retrocoele should be assessed on their individual merit. Uterine flexion or version should have no influence on a woman's fitness to fly. Second and third degree uterine prolapse as well as major cystocoeles or rectocoeles may be aufficient cause for temporary self suspension from flying while the problem is rectified. High-G military or civil acrobatic flight raises interesting questions with respect to conservatively treated (pessary) uterine prolapse. I suppose that it is theoretically possible that increased +Gz loading could cause prolapse of a poorly suspended previously prolapsed uterus. This is an extremely unlikely event and although of likely nuisance value is unlikely to be incapacitating. The fitness to fly of women with conservatively managed uterine prolapse should probably be considered on their individual merits.

    I recall 'back-bar' discussion along these lines over the last few years. It was seriously believed by some male military aviators that the high-G of tactical manoeuvres would cause a normal uterus to prolapse. This caused great mirth as the discussion moved to the design of a suitable G-suit extension to prevent this 'G Induced Prolapse'.

    While not an absolute contraindication to flying the problems associated with stress incontinence may prove to be significant enough to cause disqualification. As with the gynaecological organ displacement disorders stress incontinence is very rarely a problem of healthy young women and so is unlikely to present at an initial aircrew student medical examination. Uncontrolled stress incontinence may cause sufficient discomfort, embarrassment, and hygiene problems to prompt disqualification. It seems unlikely that a woman with this degree of stress incontinence would want to continue flying anyway.

    Benign gynaecological tumours such as uterine lieomyomata (fibroids), or adenomatous polyps would not generally preclude a woman from being fit to fly. Large or complicated polyps or fibroids may temporarily disqualify a woman until adequately treated.

    The case of malignancy is not so clear cut. On the one hand ovarian, cervical, endometrial, vaginal, uterine tube, and vulval carcinomata as well as the malignant sequelae to a hydatidiform mole all have the potential for dissemination and relapse after treatment. Dissemination or relapse of a malignancy may cause sudden unexpected incapacitation especially if the metastatic deposit is located within the (.NS or undergoes rapid haemorrhagic degeneration. On the other hand it is possible to 'cure' most malignancies to a degree that relapse or complication is very unlikely. Similarly there are other malignancies, such as squamous cell carcinoma of the skin, that only disseminate in extremely rare cases. While I am tempted to recommend that any malignancy except skin SCC should disqualify a person from flying status it is probably fairer to recommend that each case be considered on its merit. Factors such as histological typing, grade and stage, mode of treatment, time since treatment, and general health would all need to be very favourable before I would endorse a patient with a malignant disease as fit to fly.

    As discussed above the majority of gynaecological conditions would not necessarily cause me to disqualify a patient from active aircrew status on medical grounds. With the exception of pregnancy and HIV infection I feel that each gynaecological disorder should be considered on its individual merit. Each case should be assessed for the likelihood of it causing sudden incapacitation, dangerously altered mental function, annoyance, disturbance, or distraction sufficient to interfere with the safe conduct of flight responsibilities, restriction of free movement or the use of equipment based on normal ergonomic design, or any inconvenience resulting in reduced effectiveness in flight. The only conditions to which I would apply a 'blanket cover' of disqualification are pregnancy and HIV infection while I would require a lot of positive prognostic indicators to award a patient with a malignancy or endometriosis a medical 'fit to fly' recommendation.