Chapter 100 Women in the Wilderness
For online-only figures, please go to www.expertconsult.com 
Over the centuries, women have strived to prove their equality with men in areas professional, intellectual, and physical. Wilderness experiences have the potential to increase a woman’s self-esteem and empowerment. Physical activity has numerous health benefits for women, including stress reduction and prevention of osteoporosis, heart disease, breast cancer, and depression.43,115 Women from around the world are reaching new “personal summits,” from a Nepalese woman climbing Mt Everest to a series of climbing expeditions by breast cancer survivors. Clothing and recreational equipment designed specifically for women represent a multibillion-dollar industry.
Gender-Based Research
In 2001, the Institute of Medicine (IOM) of the National Academy of Sciences released the report “Exploring the Biological Contributions to Human Health: Does Sex Matter?”91 The IOM report was the first significant review of biomedical research to date related to sex and gender differences. The report confirmed the importance of gender and recommended more funding for multidisciplinary research to address the issue of gender and health in all areas of medicine.
Women’s health and gender-based research initiatives have been developed at many academic institutions and organizations around the world. The number of training programs and fellowships, along with journals, textbooks, and other related publications focused on women’s health and gender medicine, has grown exponentially.*
Until recently, researchers paid little attention to gender issues in the field of wilderness medicine. The focus was predominately on the effects of extremes of environment on fertility and pregnancy outcome. Pregnant women who live at altitude experience a high rate of fetal intrauterine growth restriction. What does this mean for the pregnant short-term traveler to altitude? Certain infectious diseases carry special risks for women. They may run an accelerated or more severe course, especially during pregnancy. Infections that have a more severe course during pregnancy include malaria, typhoid, and amebiasis. Women of any age exposed to schistosomiasis through adventurous kayaking, canoeing, or rafting may become infected. Female genital schistosomiasis can lead to subtle inflammatory changes of the genital tract and a risk for future infertility.* Thus, for a woman, exposure to certain environmental extremes or pathogens at a particular stage of life may lead to severe long-term consequences.
Pre–Wilderness Travel Women’s Health Assessment
Key areas that should be addressed for any woman wilderness traveler are outlined in the Pre–Wilderness Travel Checklist for Women (Box 100-1).
BOX 100-1 Pre–Wilderness Travel Checklist for Women
For anticipated physically challenging conditions or prolonged stays, women should undergo a thorough medical assessment (Box 100-2).
BOX 100-2 Assessment of a Woman’s Health
Screening Highlights
Recommendations for a medical kit should be made and adapted to life stage and health needs. Maintenance medications should provide optimal control of medical conditions and cover planned time, emergency needs, and expected dose adjustments. Contraceptive needs should be reviewed and options explored. Basic supplies for hygienic and anticipated therapeutic needs related to menses, the urinary tract, and vaginitis should be included. Suggestions are given in Table 100-1 and Box 100-3.
TABLE 100-1 Medications for the Medical Kit for Women*
| Indication | Medication | Dose |
|---|---|---|
| Dysmenorrhea | Ibuprofen | 200 mg PO 3 tab q 6-8 hr |
| Headache/pain/fever | Acetaminophen | 325-650 mg PO q 4-6 hr; max 4 g/24 hr |
| Nausea and vomiting | Promethazine (tablet or suppository) | 12.5-25 mg PO or per rectum |
| q 4-6 hr | ||
| Ondansetron ODT (orally dissolving tablet) | 8 mg SL (under the tongue) | |
| q 6-12 hr prn nausea | ||
| Urinary tract infection | Nitrofurantoin | 100 mg PO BID × 7 d |
| Ciprofloxacin | 250-500 mg PO BID × 3 d | |
| Trimethoprim–sulfamethoxazole | 160 mg/800 mg PO BID × 3-5 d | |
| Urinary analgesic | Pyridium | 200 mg PO TID × 2 d prn burning |
| Pyelonephritis | Ciprofloxacin | 500 mg PO BID × 7-14 d |
| Yeast vaginitis | Miconazole cream or suppository | One applicator hs × 1-7 d |
| Fluconazole | 150 mg PO single dose | |
| Bacterial vaginosis | Metronidazole tablets | 500 mg PO BID × 7 d |
| Tinidazole | 1 g PO qd × 5 d | |
| 2 g PO qd × 3 d | ||
| Metronidazole vaginal gel clindamycin vaginal cream | One applicator hs × 3-7 d | |
| Menstrual regulation or breakthrough bleeding | Oral contraceptive pills | 1 qd |
| Conjugated estrogen | 2.5 mg PO qd | |
| Medroxyprogesterone acetate | 5-10 mg PO qd | |
| Nutritional supplements | Ferrous sulfate | 300 mg PO qd-TID |
| Calcium carbonate | 1250 mg PO qd | |
| Multivitamin | 1 PO qd |
These recommendations are in addition to the ones recommended for a general medical kit in Chapters 84 and 91.
BID, twice daily; hs, bedtime; PO, by mouth q, every; qd, daily; QID, four times daily; TID, three times daily.
* Suggested medications or equivalent depending on tolerance, allergy history, and patient preferences
BOX 100-3 Supplies for the Medical Kit for Women
What Makes Women Different?
Gender-Related Performance
Gender-specific differences in anatomy and physiology are mainly due to hormonal differences that vary across the life span. In general, women are smaller than men, and have less lean muscle mass and 8% to 10% more fat mass for a given body size, differences attributed to increased estrogens in the female and increased androgens in the male. Females reach physiologic and skeletal maturity and achieve peak height at an earlier age than do males. Women have a larger surface area–to–body mass ratio. Blood volume and hemoglobin, stroke volume, and cardiac output are all lower in women than in men. These and other factors contribute to lower maximal aerobic power (even for similar training status) in women. 
is the gold standard as an index of cardiorespiratory fitness. Women of comparable training status usually have 
values that are 5% to 15% lower than those of men. Correction of 
values for lean body mass does not correct the discrepancy between genders completely, which may relate to lower hemoglobin concentrations in women, leading to less oxygen-carrying capacity.51
Estrogen and progesterone can influence ventilation and thermoregulation during exercise. Women have a smaller lung capacity than men. The smaller capacity of the lungs to oxygenate blood during intense exercise may limit exercise performance in women. Control of ventilation is influenced by progesterone, which increases central ventilatory drive, affecting breathing responsiveness during exercise and at altitude.51
Thermoregulatory control varies over the course of the menstrual cycle. The thresholds at which cutaneous vasodilation and sweating are initiated are increased about +0.5° C (+1.8° F) in the luteal phase of the menstrual cycle, when progesterone and estrogen are elevated, as compared with the early follicular phase, when these hormones are low. However, these subtle thermoregulatory differences across the menstrual cycle have not been found to affect exercise performance. The physiologic mechanisms that affect adaptation and performance in women are subtle, and there is substantial biologic variability among individuals.2,96
Gender-Related Issues Concerning Environmental Exposure
Women and Altitude
Studies have found no difference in the incidence of acute mountain sickness (AMS) between women and men. In early studies, women seemed to have a lower incidence of pulmonary edema than did men.71,78,109 However, in retrospect, many of the epidemiologic studies on altitude show a predominance of male subjects; thus, these early studies may not reflect true gender predilection. Women have been found to have a higher incidence of peripheral edema than do men.77 An excellent review of the research to date on women and altitude was published.93
The earliest and probably most important response to altitude is increase in minute ventilation caused by increases in tidal volume and respiratory rate. This hypoxic ventilatory response (HVR) is mediated by chemoreceptors in the carotid bodies, which respond to a decrease in arterial oxygen pressure (PaO2) and signal the respiratory center in the medulla to increase ventilation. HVR has been closely related to adequacy of acclimatization and the risk for developing AMS.143 The degree of HVR to a given PaO2 varies among individuals and is genetically influenced. The HVR is inhibited by respiratory depressants, such as alcohol and sedatives, and stimulated by respiratory stimulants, such as caffeine and cocoa. Progesterone is a potent respiratory stimulant and acts primarily through activation of peripheral arterial chemoreceptors.
Progesterone is produced by all steroid-forming glands, including the ovaries, testes, adrenal cortex, corpus luteum, and placenta. Although progesterone has been found to increase hypoxic ventilatory response and ventilation at sea level, there is no difference between men and women in ventilatory response to high altitude.123 Despite higher levels of progesterone in women, particularly in the luteal phase of the menstrual cycle when progesterone levels increase as much as 10-fold, no difference has been observed between males and nonpregnant females in the incidence of AMS.77 The incidence of AMS is not affected significantly by menstrual phase.
Most studies on pregnancy and altitude have been done with permanent residents of high altitude.64,93 More studies are needed to evaluate the combined effects of altitude and exercise on pregnancy in the short-term sojourner. One study of pregnant sojourners at moderate altitude of less than 2500 m (8200 feet) found that the incidence of AMS during pregnancy did not differ from that during the nonpregnant state.127 Studies of high-altitude residents indicate that pregnancy and altitude act together to increase ventilation. Arterial oxygen saturation in the pregnant woman is increased by the increase in ventilation.120 However, hypoxic conditions can compromise uteroplacental circulation and cause placental hypoxia. Uterine artery blood flow may be lower at high altitude than at low altitude, which could decrease oxygen delivery to the fetus.167 The effects of reduction in uterine blood flow, decreased arterial oxygen content, and anemia in the mother suggest that fetal oxygen delivery would be compromised during exercise.64 Some studies suggest a higher incidence of spontaneous abortion in the first trimester. For women traveling to altitudes up to 2500 m (8200 feet) in the second half of pregnancy, there is little risk for fetal complications in those who otherwise have a normal pregnancy and do not smoke.89 There are no data on safety at higher elevations. Increased incidence of preeclampsia, gestational hypertension, and placental abruption have been found in women who stay at higher altitudes for periods of weeks to months. Infants of women found to have preeclampsia were at increased risk for intrauterine growth restriction (IUGR).119 Exercise has the potential to cause fetal hypoxia or preterm labor at high altitude if competition occurs for blood supply between maternal skeletal muscles and the uteroplacental circulation.92
Hot and Cold Environments
Because of lower sweat rate, women rely more heavily than do men on dimensional characteristics and circulatory mechanisms for heat dissipation in hot environments.144 Females adapt more easily than males to hot, wet environments because of lower sweat rate and decreased risk for dehydration.25 In hot, dry environments, however, a higher sweat rate is advantageous because perspiration decreases the risk for hyperthermia, provided that adequate fluid replacement is available. With acclimation to dry heat, women are able to increase the sudorific response to an extent equal to that of men. With similar acclimatization and physical training, women tolerate physical activity in hot environments as well as do men. Women planning wilderness expeditions to hot, dry destinations are advised to plan a 1- to 2-week acclimation period in a hot environment. In general, heat tolerance depends more on cardiovascular fitness than on gender.
In moderately cold environments, women on average adapt better than do men, partly because of thicker subcutaneous fat. At extreme cold temperatures, however, women may be at a disadvantage because of the decrease in insulation from lower muscle mass. Although adaptation to cold environments depends more on body size, physical fitness, and degree of acclimation than on gender, exercise performed during cold exposure may be more effective in maintaining body heat in women than in men.113 Raynaud’s syndrome is more common in women. Vasospasm precipitated by a cold environment results in numb or painful extremities, usually the digits. Rewarming the affected area is therapeutic. Preventive measures, such as wearing gloves and using hand warmers and boot warmers before exposure, are helpful. Treatment with a calcium channel blocker such as nifedipine can be used in certain circumstances.98 Suggested dosing for treatment is nifedipine IR (immediate release) tablets 10 to 30 mg orally three times a day or nifedipine SR (sustained release) tablets 30 to 90 mg orally once a day, titrated to symptom relief.
Gender-Related Issues Concerning Infectious Diseases
Wilderness travel may increase exposure to infectious diseases. There are some differences in pathology when anatomic differences or physiologic differences (e.g., pregnancy) are taken into account.105,151
Ideally, all women should update routine and travel-related immunizations prior to pregnancy. Because maternal vaccination decreases risk to the unborn child, preconceptional immunizations are preferred to vaccination during pregnancy. Because as many as 50% of pregnancies are unplanned, women of reproductive age should be encouraged to update their regular and travel-related immunizations at all regular checkups. There are some travel-related infections, which are a risk for women, for which there are no preventive immunizations to date. For example, immunity is compromised during pregnancy, making a woman more likely to become infected with malaria. Malaria during pregnancy is an important cause of maternal mortality, spontaneous abortion, and stillbirth. Most of the studies on malaria during pregnancy have been done on pregnant women living in endemic areas. These studies have demonstrated that women living in endemic areas have an increased susceptibility to Plasmodium falciparum infections during pregnancy, compared with women who are not pregnant. Increased susceptibility to malaria during pregnancy may be due to sequestration of parasites in the placenta or suppression of selected components of the immune system associated with increased production of several hormones and other proteins.59
Female genital schistosomiasis (FGS) has been associated with a wide range of pathobiologic manifestations, such as infertility, miscarriage, and preterm delivery. Women may have lesions of the vulva, vagina, cervix, uterus, and fallopian tubes.66,134 The risk for schistosomiasis in women adventure travelers and expatriates living in endemic areas is considerable.52,104,164 The Centers for Disease Control and Prevention (CDC) investigated the incidence of schistosomiasis among expatriates in Malawi. Of 917 persons serologically tested, 302 (33%) had schistosomal antibody; of these, 292 (93%) had antibody to Schistosoma hematobium.50 After recreational exposure (swimming, wading, kayaking) in the water of the Nile river in Uganda, 17% of 69 persons had evidence of schistosome infection. Physicians may be confronted with parasitic infections causing gynecologic pathology, not only in women originating from endemic countries but also in women who travel to exotic and subtropical countries for work or wilderness expeditions.57 Women should be educated about the risk of female genital schistosomiasis, and preventive measures and avoidance.55 A local recommendation is to self-medicate with praziquantel as a “postexposure prophylaxis pill.” This recommendation does not prevent infection or the disease. Praziquantel acts against the mature schistosome parasite. It is most effective if taken after the parasite has developed to the adult stage, which is at least 4 to 6 weeks after exposure. Recommended dosing for praziquantel is 40 mg/kg/day orally divided into 1 or 2 doses for 1 day for S. haematobium, S. intercalatum, and S. mansoni. Praziquantel 60 mg/kg/day divided into 1 or 2 doses is recommended for S. japonicum and S. mekongi. An alternative choice of treatment for S. mansoni is oxamniquine 15 mg/kg orally one time.63a
Hepatitis E is a major cause of hepatitis outbreaks in India, Nepal, China, Pakistan, Africa, and the former Soviet Union, and has been reported from Central America and Southeast Asia. Transmission of the virus occurs through fecal–oral exposure. Most outbreaks result from fecal contamination of drinking water. In nonpregnant women, severe disease occurs in less than 1% of individuals. Hepatitis E infection acquired during pregnancy, however, has a mortality rate of 15% to 25%.49,125 The causes of increased severity during pregnancy are not known. Hepatitis E infection acquired during the third trimester is associated with fetal morbidity and mortality. A vaccine is being tested in clinical trials.145 Passive immunization with immune globulin is not effective in preventing hepatitis E infection.88 Ideally, pregnant women should not travel until after delivery to an area with a high risk of hepatitis E.
Practical Issues for Women During Wilderness Travel
Women between the ages of 10 and 50 years menstruate on average once a month, with a high degree of individual variability. Women should be prepared to experience changes in their cycle and premenstrual symptoms during wilderness travel. Changes in exercise, diet, sleep patterns, and time zones can affect the hypothalamic–pituitary axis and cause menses to become irregular or cease. It is helpful for women on long-term expeditions to chart their cycles. Guidelines can be followed in cases of amenorrhea or dysfunctional uterine bleeding.3,47 Reproductive-age women who are sexually active with men should carry pregnancy tests to rule out pregnancy if they miss a menstrual period. The options for feminine hygiene products that might be the best for a particular trip should be considered. Environmental considerations, such as the weight or bulk of the products and their disposal, should be considered. A number of alternative menstrual products are available (Figure 100-1). One example is a soft reusable rubber cup (the Keeper) that is reported to last 10 years. Another option is a menstrual cup (Instead), which is sold for single use and can easily be washed and reused. Feminine hygiene products can also be used for wilderness first aid. For example, tampons may be used to stop nose bleeds or as ear plugs, and menstrual pads may be used as compression dressings for wound management (Figure 100-2, online).
FIGURE 100-2 Multiple uses of feminine hygiene supplies in the wilderness.
(Courtesy Susan Anderson.)
Controlling the Menstrual Cycle
Some women prefer not to have a menstrual period during long-distance trekking, bicycling, or other endeavors. Women have the option of controlling their menstrual cycles by taking oral contraceptives or using a contraceptive patch or ring without a hormone-free interval. This option decreases the need for menstrual supplies and reduces premenstrual symptoms. “Tri-cycling” involves taking three to four cycles continuously without the pill-free days. Women should be warned that a small amount of breakthrough bleeding may occur, because the endometrium may not remain stable without the physiologic curettage of the pill-free interval.47
Another option to decrease menstrual bleeding is to try a method of contraception that leads to thinning of the endometrium over time and amenorrhea in many women. Examples of such methods include progestin-only pills, Depo-Provera, or the progesterone intrauterine device (IUD) (Table 100-2). However, in some women, progestin-only contraception may be less predictable for cycle control and lead instead to irregular bleeding or spotting between menses. If a progestin-only method is chosen, it is recommended that it be started at least 3 to 6 months in advance of the trip in order to evaluate the effect on the menstrual cycle.
Menstrual Cycle Disturbance
Menstrual cycle disturbance can occur at any age and is one of the most frequent reasons a woman seeks medical care.87 Among highly trained athletes and in environments that impose extreme physical and psychological demands, such disturbances can be found in greater than 50% of women not taking oral contraceptives (OCs). Menstrual problem during long-distance hiking was found to be the most common complaint of women backpackers. A study of backpackers on the Appalachian trail found that 87% of normally menstruating women had menstrual abnormalities while backpacking.39 Menstrual cycle complaints are also common at high altitude. Mountain ascent, in combination with other stressors, such as time change, cold, and weight loss, is likely to modify the menstrual cycle.
Understanding menstrual cycle abnormalities requires a basic understanding of the normal menstrual cycle (Figure 100-3). In premenopausal women, the hormones progesterone and estrogen fluctuate. Normal cycles occur at regular intervals, require ovulation, and typically average 28 days (range, 21 to 35 days). By convention, the first day of the menstrual cycle corresponds to the first day of the menstrual period, which usually lasts about 4 days (range, 3 to 7 days). The onset of menstrual bleeding represents desquamation of the functional endometrium, resulting from progesterone withdrawal in the absence of conception during the previous cycle, and coincides with recruitment of a new group of primordial follicles for maturation. The first stage of the menstrual cycle, up to the time of ovulation, is referred to as the follicular phase, or endometrial proliferative phase. In the early follicular phase, estrogen and progesterone levels are low. In the late follicular (also called the preovulatory) phase (days 8 to 11), there is a brief surge in estrogen levels, which promotes ovulation. The second stage is the luteal phase, or endometrial secretory phase. After ovulation, there are increases in the levels of estrogen and progesterone, which peak at about days 19 to 21 and then decrease until the following menstrual phase. During the menstrual cycle, pulsatile release of gonadotropin-releasing hormone (GnRH) by the hypothalamus occurs hourly during the follicular phase and every 1.5 hours during the luteal phase. Factors that disrupt the normal pulsatile release of GnRH or reduce the ability of the pituitary to respond to it are the major contributors to menstrual cycle abnormalities in premenopausal women.40 In women who use OCs, the contraceptive patch, or contraceptive ring, the hormone levels are elevated when the hormone (active) pills (or patch or ring) are taken (normally 3 weeks) and decrease during the week of placebo (no pill or no patch or no ring) interval. After menopause, the levels of circulating estrogen and progesterone decrease substantially; estrogen replacement (or combined estrogen and progestin) increases the levels of these hormones.
FIGURE 100-3 Normal human ovarian and endometrial (menstrual) cycle. FSH, Follicle-stimulating hormone; LH, luteinizing hormone.
(Modified from Shaw ST Jr, Roche PC: Menstruation. In Finn CA, editor: Oxford reviews of reproduction and endocrinology, vol 2, Oxford, UK, 1980, Oxford University Press.)
Causes of Abnormal Uterine Bleeding
Historical information is useful in developing a presumptive etiology and empiric therapeutic approach for AUB, particularly in the absence of laboratory resources. Past history includes age at onset of menses, regularity of menses, usual length of menses and blood flow, perimenstrual symptoms, medical problems, pregnancy history, sexually transmitted infection (STI) history, surgical history, and basic endocrinologic review of systems.87 The current problem is then characterized by changes in the frequency of bleeding, amount of flow, new symptoms, relationship to activities, recent sexual history, systemic symptoms, weight change, change in medications or use of other health-related products, and change in exercise patterns.
Anovulatory Women
In contrast, anovulation can be caused by inadequate release of gonadotropins from the pituitary, which leads to decreased estrogen production and presents as amenorrhea. Amenorrhea can be a symptom of the female athletic triad,92,97 which includes disordered eating, amenorrhea, and osteoporosis. More commonly, anovulatory cycles and amenorrhea result from changes in a woman’s usual routine of sleep, diet, and exercise patterns, all of which are extremely common to a wilderness experience.
Menopause is associated with amenorrhea as a result of cessation of ovarian estrogen production and inactive atrophic endometrium. Occasionally, a menopausal woman may produce sufficient estrogen from peripheral conversion of ovarian and adrenal androgens to stimulate the lining and cause resumption of bleeding. Postmenopausal bleeding can also be due to atrophy. Although postmenopausal bleeding is usually mild and does not need emergent treatment, a medical evaluation is important to rule out more serious causes, such as underlying malignancy.3
Self-Diagnostic Pregnancy Tests
Pregnancy tests are helpful to evaluate amenorrhea, vaginal bleeding, pelvic pain, and other symptoms that may be related to a pregnancy. For women who are sexually active with men, pregnancy tests should be carried in the medical kit. Urine pregnancy kits are not always available in remote areas, and the reliability of kits in some countries is not known. Pregnancy test kits have limited shelf lives, so the expiration dates should be checked. Environmental extremes can affect accuracy of the test, so the manufacturer’s recommendations regarding storage should be observed. As with most self-diagnostic tests, it is important to review the test procedure with the woman before travel.53
Contraceptive Options during Wilderness Travel
Contraceptive advice is an important area to address for all women wilderness travelers of reproductive age (Table 100-2). The number of women who experience unplanned pregnancy is estimated to be 50% of all pregnancies. The choices of contraceptive options include lower-dose oral contraceptive pills, several new oral progestins, progestin-only implants, and a progestin-bearing IUD. Certain delivery methods, such as the contraceptive patch and vaginal ring, offer excellent options for wilderness travelers. Some methods do not require daily compliance with taking a pill at the same time every day, which might be difficult to remember during an expedition. The other main advantage is that certain methods do not rely on drug absorption that could be affected by a gastrointestinal (GI) illness such as nausea, vomiting, or diarrhea. Contraceptive efficacy is improved with use of the contraceptive patch or ring, and there is less risk for irregular bleeding due to fluctuating hormone levels.36,82
Wilderness medicine providers should take advantage of current journal articles, reference books, and Internet websites with information regarding contraception, because this is a rapidly changing field.36,65,82 Relevant websites include:
Barrier Contraceptives
The most common barrier contraceptives used during travel include the diaphragm, cervical cap, sponge, vaginal spermicide, and male condom.82 Barrier contraceptive methods have the widest safety profile, excluding latex allergy and method failure resulting in pregnancy, but all have the same disadvantages for regular use in a wilderness setting. Failure rates even under ideal use with a spermicidal foam or gel are relatively high, estimated at 20% to 30% with “typical use” and 6% to 20% with “perfect use.” The compounds in barrier devices are variably susceptible to extremes of heat or cold, which may compromise their tensile strength and effectiveness. Some couples find these methods inconvenient and messy, which might discourage compliance in an environment not conducive to cleanup. Bulk and weight complicate transport of sufficient spermicidal compound. Barrier methods decrease risk for gonorrhea, chlamydial infection, and human immunodeficiency virus (HIV) transmission, but offer minimal protection against human papillomavirus (HPV) or genital herpes simplex virus (HSV).
Transdermal Hormonal Contraception
The U.S. Food and Drug Administration (FDA) approved the first transdermal contraceptive patch in 2001. The contraceptive patch is a matchbook-sized device that is placed on the skin (abdomen, upper outer arm, buttocks, or upper torso [not the breasts]). It consists of a three-layer matrix with an outer polyester protective layer and a medicated adhesive layer that contains the contraceptive steroids. A clear, polyester release liner, which protects the adhesive layer, is removed before application. The patch results in daily hormone release of 22 mcg of ethinyl estradiol (EE) and 150 mcg of norelgestromin. The hormones are absorbed into the blood and reach a steady state in 2 days. Each patch lasts 7 days. The patch is started on day 1 of menses and replaced weekly for 3 weeks. Week 4 is patch free. Each patch should be placed at a different site. Efficacy is similar with various application sites. Contraceptive efficacy is not thought to be affected by humid climates, vigorous exercise, exposure to saunas, or water baths. The patch has similar side effects to OCs, with the addition of occasional mild to moderate application-site reactions and an increased incidence of breast tenderness during the first few months of use. Most women have found the patch to be more convenient than a daily pill when traveling. There are no hormonal peaks and troughs. It is easy to check to make sure it is in place. Taking oral antibiotics is not believed to interfere with efficacy. The FDA has issued a warning about Internet sales of counterfeit contraceptive patches.56 To discard a used patch, it should be folded in half and discarded in solid waste garbage, not flushed down a toilet.
Vaginal Ring
NuvaRing is a soft, flexible, and transparent ring made of an ethylene vinyl acetate copolymer. It has an outer diameter of 54 mm and a cross section of 44 mm. There are two steroid reservoir cores in the ring that provide daily hormone release of 15 mcg of EE and 120 mcg of etonogestrel (an active metabolite of desogestrel). NuvaRing provides hormone bioavailability comparable with an OC, such as desogestrel ethinyl estradiol (Ortho-Cept). It is inserted by a woman and removed after 3 weeks. Following one “ring-free” week, a new ring is inserted. If the ring is expelled accidentally, it can be washed and reinserted. If the ring is out for more than 3 hours, a backup contraceptive method is recommended. Advantages include good contraceptive efficacy, with continuous release leading to better compliance. The ring does not depend on GI absorption, so will continue its effectiveness even if the woman has a GI illness.72 Side effects are rare, and include prolonged menstrual bleeding, vaginal discomfort, and foreign-body sensation. Use of common antibiotics such as amoxicillin and doxycycline does not appear to affect efficacy.61
Special Issues Related to Hormonal Contraceptives and Wilderness Travel
Absorption
Nausea, vomiting, or diarrhea during travel may decrease absorption of the pill. If vomiting occurs within 3 hours of taking a pill, a woman should take another. If a replacement pill cannot stay down (equivalent to missing a pill), she should use a backup method for the rest of the month. Elimination of the pill-free interval and starting the next package right away can also be considered if the missed pill was less than 7 days from the end of the package. For continued nausea and vomiting, some clinicians recommend inserting the OC pill into the vagina for absorption, although efficacy has not been evaluated in clinical trials. Estrogens are actually absorbed better through the vaginal mucosa than through the GI tract.5,32 For women at risk for GI illness during travel, a contraceptive patch or a ring is ideal.
Drug Interactions That May Affect OC Efficacy
A common question is whether antibiotics affect OC efficacy. The metabolism of OCs is increased by any drug that increases liver microsomal enzyme activity. Despite numerous case reports of penicillins, tetracyclines, metronidazole, and nitrofurantoin causing contraceptive failure in humans, no large-scale studies have demonstrated that antibiotics other than rifampin lower steroid blood concentrations.29,82,86 However, individual women have been shown to have decreased ethinyl estradiol while taking antibiotics. Because these women cannot be identified in advance, most clinicians and the OC package insert take a conservative approach and advise women to use a backup method of contraception. Because these women cannot be identified in advance, most clinicians and the OC package insert take a conservative approach and advise women to use a backup method of contraception when taking antibiotics.60 Recent data suggest that efficacy of the contraceptive patch and the ring are not affected by concurrent antibiotics.61
Gender and the Risk for Venous Thromboembolism (VTE).*
The incidence of VTE in young women is estimated to be 1 to 3 per 10,000 per year. Pregnancy increases this risk three to five times, low-dose contraceptives increase the risk by three to four times.107 The association between pregnancy and venous thromboembolism (VTE) is well established, and pulmonary embolism (PE) is one of the leading causes of peripartum mortality.158 Increased risk for VTE is associated not only with the use of OCs but also hormone replacement therapy and estrogen-antagonist therapies. These exposures are unique (pregnancy and OCs) or nearly unique (estrogen agonist and antagonist therapies) to the female gender.121 The risk for VTE may be important to consider in some wilderness settings, such as high-altitude expeditions, that may include a combination of risk factors such as immobility due to inclement weather, dehydration, cold, and exhaustion.
OCs are believed to exert their effect on the risk for thrombosis by causing alterations in endogenous coagulation and fibrinolytic systems. OC use is associated with increases in prothrombin, fibrinogen levels, and factors VII, VIII, and X, and with decreases in factor V levels. Use of OC is associated with a twofold to threefold increase in the risk for VTE. Women who use third-generation OC drugs containing gestodene or desogestrel as the progestin component likely have a slightly greater risk than women who use second-generation preparations. Obese patients and smokers are at increased risk.161
The term hormone replacement therapy (HRT) refers to a variety of estrogen or combined estrogen and progestin formulations prescribed to relieve menopausal symptoms and prevent osteoporosis. Effects of HRT on the coagulation system appear to be similar to those of OCs, with evidence for increased markers of coagulation, factor VII levels, and activated protein C (APC) resistance, and a decrease in antithrombin levels.139
The Breast Cancer Prevention Trial68 reported a threefold increased risk for PE and a nonsignificant increased risk for deep vein thrombosis (DVT) among women with breast cancer receiving tamoxifen.
Pregnancy is a well-recognized risk factor for thromboembolic disease. Physiologic changes that occur during pregnancy pose several risks for VTE. Hypercoagulability results from increased levels of fibrinogen and several clotting factors (II, VII, VIII, IX, X, XII), as well as decreased levels of inhibitors of coagulation, such as protein S. This altered state of coagulation persists throughout pregnancy and for up to 6 weeks postpartum. Venous stasis occurs from hormonally induced increases in venous distensibility and capacity, as well as vena cava compression by the enlarging gravid uterus.158 Vascular injury resulting from childbirth, especially cesarean birth, further escalates risk for VTE during the peripartum period; cesarean birth is associated with increased incidence of VTE compared with vaginal delivery. Other risk factors for VTE during pregnancy include obesity, maternal age, parity, prolonged bed rest, infection, prior history of VTE, and thrombophilia.
Exposure to high altitude may be a risk factor for thromboembolic events due to polycythemia, dehydration, and cold, but increased risk from use of OCs or other hormonal therapy has not been systematically studied at high altitude. As a precaution, women planning high-altitude excursions who desire hormonal contraception should consider a combination pill containing the lowest dose of ethinyl estradiol (20 mcg) or its equivalent or a contraceptive patch or ring. Venous thromboembolism occurs more frequently in users of third-generation OCs (30 mcg estrogen with desogestrel or gestodene as progestins), but is a potential risk with all hormonal methods.94,111 Contraceptive options for women at high risk of thrombolic events include an intrauterine device or progestin-only method.13
If a thrombotic or thromboembolic event is suspected on an expedition, aspirin therapy may be started empirically while awaiting medical evacuation. However, there are no studies evaluating the role of aspirin in reducing DVT related to altitude or air travel. Aspirin prophylaxis has been shown to reduce the incidence of venous thrombosis and pulmonary embolism in high-risk medical and surgical patients.138
Intrauterine Devices
An IUD is a highly effective and convenient form of contraception, especially for the parous woman in a stable relationship. Women who cannot take estrogens because of a history of breast cancer, thromboembolism, or diabetes, or who are breastfeeding, are candidates for an IUD.13 Ideally, the IUD should be inserted at least 3 months before departure, because complications occur most often within the first month after initial insertion. IUDs are occasionally associated with increased menstrual flow, dysmenorrhea, intermenstrual spotting, and expulsion. However, the Copper T 380A IUD and the levonorgestrel system (LNG-IUS or Mirena) carry minimal risks for these side effects. The LNG-IUS releases about 20 mcg of levonorgestrel per day, which is about 10% of that of a levonorgestrel-containing OC. The levonorgestrel system requires replacement every 5 years. The Copper T 380A IUD is effective for 10 years or longer. For certain women, an IUD is a great option for wilderness travel.11
The most serious risk, affecting less than 1% of IUD users, is acute or indolent pelvic infection that might become clinically significant in the wilderness. The risk for this is greatest within the first month after insertion or replacement of the IUD and among women at increased risk for STIs. Women with multiple partners, previous pelvic infections, unrecognized chlamydial infection or gonorrhea, recurrent episodes of bacterial vaginosis, or tobacco use are at highest risk. When acute PID occurs with lower abdominopelvic pain, peritonitis, purulent vaginal discharge, and fever, the IUD should be removed immediately by simple traction on the string protruding from the external cervical os. Broad-spectrum antibiotics should be started. Evacuation is mandatory when the device cannot be removed. Pelvic infection should be suspected, even without fever and peritoneal signs, if irregular bleeding occurs, particularly when accompanied by pelvic discomfort and discharge. When the IUD is removed at this stage, the infection may respond to therapy with oral or simple parenteral antibiotics.11
Emergency Contraception
EC is defined as a method of contraception that women can use after unprotected intercourse or contraceptive failure to prevent pregnancy (Table 100-3). EC should be used when desired in cases of unprotected intercourse, contraceptive failure, or sexual assault. EC should be included in every woman’s wilderness medical kit. It decreases a woman’s risk for pregnancy from an 8 : 100 to 1-2 : 100 ratio. The Princeton Emergency Contraceptive website (http://ec.princeton.edu) has an excellent review of EC options and commonly asked questions. It also has a chart of how a number of brands may be used as EC and what options are available in different countries.23,82,100
There are four major categories of EC available worldwide: progestin-only pills; estrogen–progestin combined oral contraceptive pills; a new selective receptor modulator pill (ulipristal acetate), available in Europe and recently approved for EC use in the United States (August 2010); and mifepristone, which is only available in China and Russia. EC options available in most countries include the progestin-only option levonorgestrel or estrogen–progestin combination OC pills. Recent studies have shown that Plan B levonorgestrel is equally effective when both doses of pills (1.5 mg total) are taken at the same time, rather than when the 0.75-mg tablets are taken 12 hours apart.82 The “one dose” option may improve compliance and thus effectiveness. Plan B is better tolerated than are the other ECs that contain estrogen. Presently, Plan B is the only option packaged specifically for EC available in the U.S. and Canada. In the U.S. and many other countries, EC is available over the counter. Ideally, it is best to complete EC as soon as possible after unprotected intercourse, preferably within 72 hours. Ulipristal acetate is effective up to 120 hours after unprotected intercourse, but requires a prescription. New data are encouraging that all the options for EC may be effective for up to 120 hours.74,100
Administering an antiemetic may be helpful when using OCs containing estrogen and progesterone. If there is persistent nausea and vomiting, emergency contraception pills may be administered vaginally.23
If unprotected intercourse occurs, Plan B progestin EC can be taken within 120 hours, followed immediately by initiation of a combined hormonal method (OCP, patch, ring). Two to 3 weeks later, a urine pregnancy test should be done to rule out pregnancy. In the rare case that a woman becomes pregnant following EC, combined hormonal contraception use has not been found to increase teratogenic risk.36
Breast Health
Clothing and sports equipment should be tested ahead of time for breast comfort. Sports bras are helpful for many women. All women should examine their breasts for masses before travel. Women older than 40 years and women with a strong family history of breast cancer should have a breast examination and mammography screening before travel. Although there are reports of self-diagnosis and treatment in the field,84 a breast mass would ideally be evaluated before travel to a remote location.
A woman who has had a mastectomy and lymph node dissection with resulting lymphedema may want to use an arm sleeve to decrease swelling during air travel and extended backpacking or trekking expeditions.81 Women should be taught how to recognize cellulitis and how to treat it with appropriate antibiotics.152 There have been no large studies on the safety of breast implants at altitude or during scuba diving. In one small study evaluating breast implants in simulated dives, there were no ruptures, but there were morphologic distortions in shape in some of the implants. The repetitive stress associated with the number and depth of the dives may lead to a decrease in the life span of the prosthesis.63,76 Issues pertinent to breastfeeding are discussed in the section on pregnancy.
Urinary Tract Issues
Measures to prevent UTIs include adequate hydration and urination when needed, even if there is no formal facility or a tree behind which to hide. Some women find the squatting position awkward. Practicing deep knee bends before the trip is helpful. Women should consider attire, such as a free-flowing skirt, that would both facilitate this stance and add some privacy. There are a number of plastic and paper funnels that have been designed to assist women to urinate in the standing position (Figure 100-4). These methods require practice to avoid getting wet. It is best to be with one’s back to the wind and to point the funnel downward. When wearing pants, it is important to make certain that the zipper or other opening is long enough to fit the device. The funnels are especially useful in extremes of cold weather and altitude when a woman might not want to wear a skirt or pull down her pants. It is also possible to connect the device to a longer tube that is connected to a container for urine storage (traveljohn.com) if it is too cold to urinate outside the tent or a woman is on a long road trip.
Options for reusable and/or disposable female urine devices (FUD) include:
If an older woman has a problem with stress incontinence or bladder control, she should consult a physician specializing in female urinary tract problems before the trip. For minor problems, women can be taught to do pelvic floor exercises and to bring a supply of panty liners. Older women may experience vaginal dryness and urinary frequency or urgency without dysuria. Recent data suggest that estrogen vaginal cream, vaginal rings, or a low-dose pill inserted intravaginally may decrease urogenital dryness and frequency symptoms.28,33,34
Vaginal Discharge or Itching
Environmental conditions and constraints on hygiene during wilderness travel promote a change in a woman’s vaginal ecosystem that may result in increased vaginal discharge and vulvar itching and irritation. Causes include infection, contact irritation due to a new soap or feminine hygiene product, or contact with poison oak or other irritating plant when urinating. Because diagnostic capabilities in the wilderness are limited, clinical features (Table 100-4) can help guide diagnosis and treatment. Women should be taught self-diagnostic skills and carry appropriate treatment in the medical kit. Even if a woman has never before had a vaginal infection, she should be prepared for this possibility, especially for extended itineraries. Women should be advised to seek medical evaluation if the symptoms do not improve with self-treatment. The most common causes of vaginitis during wilderness travel are yeast infection, bacterial vaginosis, and chemical irritation.
Vulvovaginal Candidiasis
Symptomatic yeast infections are often referred to as vulvovaginal candidiasis (VVC). About 80% to 90% of these result from overgrowth by Candida albicans. Risk factors for yeast infections include pregnancy, hormonal therapy, recent antibiotic use, corticosteroid therapy, postovulatory phase of menstrual cycle, frequent coitus, condom use, and intravaginal use of spermicidal compounds.12
The foundation of treatment for VVC is a variety of azole derivatives, many of which (e.g., butoconazole, clotrimazole, miconazole, tioconazole) are available over the counter as topical creams, vaginal tablets, and suppositories. Therapy periods range from 1 to 14 days, depending on the formulation and severity of the infection. Generally, a treatment regimen of at least 3 days results in a greater initial response rate and a lesser chance of immediate recurrence. Symptoms related to inflammatory vulvar involvement respond most rapidly to the topical creams, although their application at first may be accompanied by burning pain. Oral fluconazole (150 mg, single dose) is a convenient therapeutic agent to include in the basic pharmacopoeia of a wilderness expedition. Women with frequent recurrences or predictable outbreaks at specific times in their cycle, most often premenstrually, should consider prophylactic suppressive therapy with fluconazole (150 mg orally) or clotrimazole (500-mg vaginal tablet) weekly.150 To treat local symptoms, a low-potency steroid cream can be used in conjunction with a topical antifungal.
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