E. Lawrence-Wood,1 S. Kumar,2 S Crompvoets,3 B. G. Fosh,4 H. Rahmanian,1 L. Jones,1 S. Neuhaus1
Background
There are clear evidence gaps relating to health outcomes of servicewomen and female military veterans (here included as servicewomen). In addition to physical health, mental wellbeing and maternal health, there is limited literature regarding their sexual and reproductive health, particularly within an international context.1 Internationally, a recent increased focus on the health of servicewomen and female veterans reflects both increased numbers of females in the military and removal of duty restrictions. Consequently, specific policies addressing pregnancy, breastfeeding and return to work have been developed, although research evidence to inform these is lacking. Identifying available evidence and mapping evidence gaps is critical to develop policies that will support the future female military workforce. Therefore, as a basis to address these emerging issues, an evidence mapping review was conducted to identify reproductive and sexual health issues faced by servicewomen, and establish the evidence gaps and target areas for future research.
Method
A systematic literature search of library databases was undertaken in April 2015, including Embase, Medline, PubMed, Web of Science, Cumulative Index to Nursing and Allied Health Literature (CINAHL), and the Cochrane Database. The following Medical Subject Heading (MeSH) terms were searched in title, abstract and keyword fields: servicewomen; veterans; military; Defence; reproductive health; menstruation disturbances; menopause; premature; fertility; contraception; contraception behaviour; pregnancy; female urogenital diseases; pregnancy complications; obstetric surgical procedures; hydatidiform and mole. To broaden the search, the reference lists of all included studies were examined to identify any other potentially relevant papers (Pearling). Results were limited to studies published in English, from the year 2000 to the present.
Exclusion criteria from the initial search included:
•Not published in English,
•Published prior to 2000,
•Not published in peer-reviewed journals,
•Editorials or correspondence,
•Did not involve servicewomen or female veterans,
•Did not report reproductive or sexual health issues.
Included studies were assessed on their level of evidence according to the Australian National Health and Medical Research Council (NHMRC) hierarchy of evidence,2 and data regarding country of origin, study aim(s), population, sample size and key findings (Table 1), were initially extracted from ninety-six relevant studies. Inclusion criteria were further refined to focus on:
•Servicewomen and female veterans of the military forces (active service)
•Sexual and reproductive health impacts, effects of and associations with military service
Where possible a non-service comparison group was preferred, however broader criteria were utilised to provide the most comprehensive overview of available published research. Due to the limited research
Figure 1 can be found in the download version
in this area, studies of lower evidence addressing issues of interest were retained, though findings were interpreted with caution. A total of 76 papers were independently evaluated by the lead author and another reviewer, with 46 included in this review (see Figure 1).
Results
The majority of published research in this area comes from the United States (US), which has the largest cohort of females in active military service. Initial assessment identified the following key areas where impacts of active military service could be examined: (1) general reproductive and sexual health; (2) menstrual regulation and menopause; (3) birth control; (4) pregnancy incidence and birth outcomes; and (5) post-pregnancy health and wellbeing. Papers were grouped accordingly, with active service and deployment-specific findings examined separately where appropriate. An assessment of the available evidence is summarised for each outcome, and conclusions regarding the state of evidence in the area as a whole is presented, including an overview of notable gaps. Key study information and findings, organised by topic, are summarised in Table 1.
General reproductive and sexual health
There were only a small number of studies that addressed general reproductive and sexual health. This included two reviews, one small qualitative study, and two large administrative database studies. Evidence from these suggests higher healthcare use by females compared to males, of which a substantial proportion relates to gynaecological, contraceptive and menstrual issues. Sexual assault, unintended pregnancy on deployment, pregnancy termination, and infertility among female veterans were also highlighted. However, in most studies there was insufficient evidence to determine whether these issues are specific to military service.
A small qualitative study from Doherty and Scannell-Desch3 indicated gynaecological infections, suppression of menstruation, unintended pregnancy and other experiences (e.g., difficulties accessing bathroom and toilet facilities, hygiene and cleanliness issues, personal safety) as important issues in the deployed environment. While this study was limited in terms of size and scope, the findings are consistent with those from earlier work in this area.4 These types of gynaecological issues may also persist post-deployment.5 Menstrual disorders and endometriosis were the most frequent reproductive health diagnoses among US servicewomen aged 18–44 years.6,7 Additionally, Katon et al.6 reported a higher prevalence of mental health diagnoses among women with these conditions, possibly reflecting a greater need for attention.
Recent studies demonstrate an emerging problem of sexual assault in the military with 11-48% of female veterans reporting sexual trauma during their service.2,8,9 Military sexual trauma can lead to deleterious physical and psychological comorbidities, including termination of pregnancy, delayed or avoidance of pregnancy as well as infertility, sexually transmitted infection, posttraumatic stress disorder and postpartum dysphoria.10,11
Table 1. Summary of papers included in review, organised by key topics.
General reproductive and sexual health
[table id=1 /]
Menstrual regulation
[table id=2 /]
Menopause
[table id=3 /]
Birth control
[table id=4 /]
Unintended pregnancy
[table id=5 /]
Pregnancy incidence and outcomes
[table id=6 /]
Birth outcomes
[table id=7 /]
Post-pregnancy Health and Wellbeing
[table id=8 /]
Menstrual regulation and menopause
Research examining menstrual regulation among servicewomen is somewhat limited, predominantly comprising retrospective self-report data, however this does include a number of large administrative database studies, and supplementary qualitative findings. The issues arising most consistently in this area related to the use of Oral Contraceptive Pills (OCPs) to suppress menstruation, particularly within the deployed environment, the real or implied barriers to access and use of OCPs and the lack of understanding about OCPs, particularly in relation to menstrual suppression.
Overall, there appears to be a disconnect between desire to reduce menstrual burden and actual use of OCPs for this purpose.12 Using OCPs to suppress menstruation may be beneficial in training and deployed environments13 given that unplanned pregnancy can impede deployability and menstruation has potentially adverse impacts in the deployed environment. Although deployed women have reported positive attitudes toward menstrual suppression, these attitudes rarely translated to behaviour. For example, Powell-Dunford et al.14 found that among a sample of US active duty servicewomen, 86% wanted to suppress menstruation, particularly during deployment and field training, but only 7% reported using OCPs to do so. Willingness to consider OCPs for this purpose was positively correlated with the self-reported burden of menses in this study, and in fact other research suggests lower reported burden of menstrual symptoms in women who do suppress menses.15,16 Despite these attitudes, compliance with OCP use can be poor in deployed environments.15
Barriers to access and lack of knowledge about OCPs may account for their under-use in women reporting a desire to reduce the menstrual burden.16-19 In a study of deployed US servicewomen,20 one third reported being unable to access their desired contraception and 40% had difficulty obtaining prescribed contraception. More long-term methods of contraception including IUDs were unavailable or discouraged. Whether this issue translates to other international contexts is not clear. In addition to access difficulties, Enewold et al.18 also found a lack of knowledge and understanding about effective OCP use among US servicewomen, particularly among younger women. Older women, in contrast, had greater knowledge about and were more likely to use OCPs. This study also reported inter-service differences in OCP use, with higher rates in the US Air Force compared to Army.
Despite the increasing population and age of female personnel,1 the issue of menopause is largely unexamined. Of the two studies investigating menopause, while utilising large sample sizes, neither were able to draw conclusions regarding the impact of, or relationship with service. However, as menopause generally occurs before the regular retirement age of sixty five8, it is likely that many women in the armed forces will experience menopause during their career. Importantly, given the association between age and seniority, the potential for functional impact of menopause in senior levels of service should be acknowledged.
Hormone Replacement Therapy (HRT) can effectively reduce adverse impacts of menopause on everyday functioning.21 Accordingly, Haskell et al.22 examined both use and discontinued use of HRT among US servicewomen. Women experiencing menopause at a younger age, and those who had accessed Veterans Affairs clinics were significantly more likely to continue use than other women, although the reasons for these differences were unclear. In a follow-up study, Haskell, Bean-Mayberry and Gordon23 found the majority of HRT users discontinued use abruptly, despite evidence that tapering use is associated with reduced recurrence of menopausal symptoms. Those who did taper their use (thus having less adverse outcomes) generally had higher income and were younger. Given apparent issues of access to hormonal contraceptives on deployment, similar barriers may apply to accessing HRT. Awareness of and access to OCPs and HRT is important in the deployment environment, given their potential functional benefits.
Birth Control
Contraception
The majority of studies examining contraceptive use among servicewomen were cross-sectional, with some retrospective and qualitative studies. The level of evidence available and lack of comparison groups limit conclusions that can be drawn. However, as with menstrual regulation, a number of issues emerged around knowledge, use of and access to birth control measures. While there is evidence supporting use of OCPs as birth control, particularly while on deployment and training, the number of women actually using them is low. Women may also be less likely to use OCPs whilst deployed, despite understanding their potential benefits, again indicating real or perceived barriers to access and use. Together these findings have implications for unplanned pregnancy and gynaecological presentations on deployment (as well as menstrual regulation).
More generally, US literature points to a gap in contraceptive understanding among military women. Van Royen, Calvin and Lightner24 found that among active duty US military women, knowledge about emergency contraceptive methods was poor; 85% were sexually active but only 62% used contraception. Although 64% were aware of emergency contraception, only 15% knew how and when to take it, and younger, unmarried women were most likely to have this knowledge. Thomas, Thomas and Garland25 explored contraceptive use and family planning among active service US Navy women, with only 40% of these using an oral or implant hormonal contraceptive, suggesting reliance on other methods (e.g., condoms). In some cases pre-deployment counselling on contraception may be inadequate, resulting in a lack of knowledge of available methods on deployment and consequent problems with access.26
Von Sadovszky et al.27 found that among US Army women, condom use overall was low, and a number of factors including ease of use and access contributed to higher use. Use was predicted by relationship type, attitudes to condoms and marital status. In contrast, in a study of sexually active US servicewomen stationed in Nigeria,28 the majority of women reported using condoms, possibly reflecting differences in perceived risk of sexually transmitted infections (STIs). Despite national polices precluding sexual relations on deployment, condom use has a role in reducing unplanned pregnancies and preventing STIs. Importantly, the availability of condoms (as well as other types of birth control) may be limited in the deployed environment. Therefore, improving access and availability is important.
Unintended pregnancy
There is a general consensus that pregnancy is incompatible with deployment.26 However, regulations regarding pregnancy testing prior to and during deployment vary across international militaries. In the Australian Defence Force (ADF), for example, pregnancy testing is mandated prior to land deployments and recommended (but optional) in the case of maritime deployments. This is not the case in many other militaries, with optional pregnancy testing prior to deployment. However, pregnancy can occur on deployment, and is not necessarily a rare occurrence. Combined with trends suggesting possible impacts of deployment and deployment exposures on conception and in early pregnancy (discussed below), this is an area requiring further research.
The prevalence of unintended pregnancy among servicewomen appears to be inversely associated with age, rank and seniority, and related to contraceptive non-use, misuse or failure.29-31 Custer et al.32 found approximately half of pregnancies among US soldiers were unintended. Although this figure is consistent with the civilian population, these rates significantly impact workforce capability because elements of active military service (e.g., deployment) are incompatible with pregnancy. Regarding deployment, Buller et al.33 reported unintended pregnancies among approximately five percent of US females during deployment to Afghanistan, a number equivalent to those reported during the Persian Gulf War.
Grindlay et al.34 explored the issue of abortion among deployed U.S. servicewomen. This qualitative study reported a lack of access to abortion while on deployment, which at times led to the unsafe practice of women attempting to terminate their own pregnancies. Similarly, Ponder and Nothnagle35 reported a lack of access to education regarding contraception, reproductive choice and support for termination of pregnancy. While conclusions regarding pregnancy termination cannot be drawn on the basis of this research, the potential implications of these anecdotal findings are significant in view of known rates of unintended pregnancies on deployment.
Pregnancy Incidence and Birth Outcomes
There is no definitive evidence that active service impacts on pregnancy likelihood, frequency of ectopic pregnancies or miscarriage. However, a small number of studies indicate a potential increased risk of miscarriage among previously deployed servicewomen, and the possibility of increased risk of birth defects. In relation to active service more generally, there could be adverse effects of occupational standing, or noise exposure, which may increase risk of pre-term labour and birth, and sedentary administrative positions, which may be associated with a greater risk of pregnancy complications (see Table 2 for a summary of evidence). Importantly, any conclusions from this research are limited by the small number of studies available.
There is limited research relating to pregnancy likelihood and pregnancy loss (including ectopic pregnancies and miscarriage) among servicewomen, however most studies do utilise large samples, and include control groups. The Armed Forces Health Surveillance Center36 reported that among US servicewomen deployed to Afghanistan and Iraq, infertility rates increased with increasing
Table 2. Summary of evidence regarding pregnancy and birth outcomes – Found in the full download
deployment number and length. Menstrual disorders (potentially a precursor to fertility issues) were also more common among females deployed longer than nine months.
Although there is no conclusive evidence that active service impacts on the frequency of ectopic pregnancies or miscarriage, trends from a large administrative data study suggest a potentially increased miscarriage risk among US servicewomen deployed to the Gulf War.37 Araneta et al.38 and Wells et al.39 reported no significant impact of Gulf War service on rates of conception, but Araneta et al. did find increased prevalence of post-deployment ectopic pregnancy and miscarriage. They argued that these higher rates of reproductive losses could be partially explained by demographic risk factors including socio-economic status, however.
A review by Rivera et al.40 showed that female veterans historically report more reproductive and gynaecological problems than the general population. In addition they are more likely than their male counterparts to seek care for infertility. Increasing numbers of US female veterans are seeking reproductive health care through the Veterans Affairs, yet little is known about the delivery of infertility care for this population.41 Two large studies utilising Department of Defence and Veterans Affairs data, examined infertility among US servicewomen. Katon et al.42 found no significant difference in rates of infertility among veterans compared to civilians, however they did find that female veterans were more likely to seek infertility treatment. Mattocks et al.43 reported that only 2% of US women veterans of Iraq and Afghanistan operations actually received infertility diagnoses, and less than a quarter of these women received infertility treatment.
Literature suggests that demographic factors may be more important predictors of birth outcomes than military service factors such as active duty, occupational exposures, vaccination and deployment; however, emerging evidence does indicate the possibility of service impacts. There is insufficient evidence from the studies to determine definite impacts of active service generally, or the specific impact of deployment on adverse pregnancy outcomes including pre-term birth and birth defects. There is limited evidence that active service may impact preterm birth. However, available evidence does indicate that deployment probably has an impact on pregnancy and birth outcomes more generally, while occupational exposures may have an effect on birth outcomes more specifically (see Table 2).
The limited research into the impact of service on birth outcomes has produced mixed findings. Compared to a control group of civilian dependents of military servicemen (thus subject to the same healthcare access and conditions), active duty servicewomen reported similar birth outcomes including infant weight and gestational age.44 Of note, this prospective study found that active duty servicewomen had significantly less social support and worked longer into their pregnancy compared to civilian women – further suggesting these factors did not impact on birth outcomes. However, women who engaged in higher levels of occupational activity can have increased risks of pre-term delivery, even after accounting for age, socioeconomic status, marital status and education.44 Consistent with this, Greer et al.45 reported that female US Marines were significantly more likely to have a spontaneous vaginal birth, with babies of lower birth weight, compared to Navy women; inter-service differences in activity levels may explain this finding.
The effect of occupational exposures is also unclear. Hourani and Hilton46 reported no significant association between occupational ‘burn pit’ exposures and pre-term birth among deployed US active duty servicewomen. However, odd ratios for adverse birth outcomes appeared consistently higher for women who had been deployed and exposed to burn pits during their pregnancy. This trend is inconclusive but suggests the need for further monitoring. Interestingly, in this same study a significant association was observed between paternal burn pit exposure and risk of birth defects for the subsequent pregnancy. However, the authors noted these findings were inconsistent with others and had no biological explanation. Therefore, this finding should be interpreted with caution. In examining the impact of active duty-related exposures among US navy women, Hourani and Hilton46 and Conlin et al.47 found self-reported exposure to heavy metals, petroleum products, pesticides, and other chemicals, were associated with adverse birth outcomes, although these effects were largely accounted for by maternal health variables. Consistent with findings reported by Hourani and Hilton,46 after controlling for health and pregnancy related variables, the only significant exposure effect on birth outcomes in this study was paternal exposure to pesticides – which was associated with increased risk for pre-term birth. Conlin et al.48 also reported no adverse pregnancy or newborn health outcomes among active duty US military women who received pandemic H1N1 vaccine during pregnancy.
Likewise, the impact of deployment on pregnancy and birth outcomes is also unclear. Conlin et al.47 and Ryan et al.49 reported no differences in rates of pre-term birth, infant malignancies or major birth defects among infants of women who deployed during their first trimester of pregnancy, compared with those who did not deploy. Wells et al.39 found no significant difference in the rates of adverse birth outcomes for Gulf War deployed female veterans, compared to a non-deployed comparison group. Doyle et al.50 were unable to determine any association between Gulf War deployment and stillbirths and malformations among the offspring of British servicewomen, due to limited sample size. However, Kang et al.37 did report a significantly greater risk of birth defects among Gulf War veterans compared to a control group, and in earlier research they found increased risk of birth defects among female Vietnam veterans.51 Together these findings highlight the need for future research regarding birth outcomes in servicewomen.
Post-pregnancy health and wellbeing
There is a dearth of research focussed on post-pregnancy health and wellbeing among servicewomen. There is little information on breastfeeding rates, workforce retention and post-partum return to work in this population, although recent data is emerging from Australia. This significant research gap has important policy and workforce implications regarding the appropriate supports for and needs of new mothers in the military. The lack of research in this area limits the assessment of evidence, however, it appears that military weight requirements may be unrealistic for new mothers, postnatal mental health issues require further research in this population, and support for breastfeeding may need to extend into the return-to-work period.
Some studies have examined post-partum physical fitness in servicewomen. Armitage and Smart52 reported poorer performance and lower fitness pass rates for US active duty Air Force women 6 months post-childbirth, compared with participants’ pre-pregnancy fitness test results. Further, Armitage and Smart52 and Weina53 found that post-partum fitness scores were significantly associated with post-pregnancy complications and weight gain. Overall, the physical fitness of women in the US military services reduces significantly between the pre-pregnancy and post-partum testing. Interestingly, Greer et al.45 compared weight standards pre- and post-pregnancy among US Marines and Navy servicewomen. Approximately one year pre-pregnancy, almost 80% of Navy women and 97% of female Marines were within accepted body weight standards. At the first prenatal visit, the proportion of Navy women within accepted standards fell to near 70%, while for Marines it remained largely unchanged (96%). Consistent with this, at 3 and 6 months post-partum, Marines were significantly more likely than Navy women to meet body weight standards, again suggesting an inter-service difference.
Appolonio and Fingerhut54 examined post-partum depression (PPD) among active duty US servicewomen and found almost twenty percent had PPD symptoms. A number of psychosocial variables were associated with PPD diagnosis, including poor social support, life stress and childcare stress. While rates of PPD in the military sample were elevated compared to those observed in the community, no military specific factors were found to significantly predict PPD. However, given the higher rates of PPD in the military sample, further research is warranted. In studying the impact of previous childbirth on the psychological health on deployment, Nguyen et al.55 found maternal depression was increased among mothers subject to combat exposure while deployed.
This finding suggests that deployment could be associated with increased adverse outcomes for mothers versus non-mothers, though the underlying mechanisms are not clear.
While few studies have examined the impacts of breastfeeding in military environments, Appolonio and Fingerhut54 reviewed evidence regarding service-related risks to breastfeeding mothers in the British Army. There was limited evidence that lead and pesticide exposure posed a risk to the offspring of breastfeeding mothers, with a recommendation that breastfeeding servicewomen be excluded from duties where these exposures are likely, including environmental duties and working in firing ranges. A recent Australian military study investigated breastfeeding initiation, prevalence, and duration in a cohort of working mothers.56 Breastfeeding rates among this cohort compared favourably with women in the general population until 9 months, coinciding with returning to work post-leave. Australian servicewomen are entitled to maternity leave as a condition of service, which may have affected initial breastfeeding rates in this study and the proportion of women continuing to breastfeed until maternity leave had elapsed.
Summary and conclusions
In summary, despite limited extant knowledge regarding sexual and reproductive health impacts of military service among women, a number of key issues were identified. There appear to be issues with knowledge of, access to and compliance with oral contraceptives among servicewomen, with two associated implications being rates of unplanned pregnancies on deployment and relief of menstrual burden through contraceptive suppression of menses. While the evidence regarding menstrual burden was mostly anecdotal, there are indications that this could be problematic in austere environments such as the Middle East. By addressing poor contraceptive knowledge and access among female personnel, menstrual burden and unplanned pregnancy could be reduced. There is some evidence indicating deployment may impact on pregnancy and birth outcomes, however it is unclear whether this is due to deployment exposures or other factors that persist post-deployment. Data trends suggest an association between active service and miscarriage, however this is statistically inconclusive. In relation to birth outcomes, evidence suggests a trend towards higher rates of birth defects among offspring of previously deployed women, although this is less the case for contemporary Middle East deployments. Again, this evidence in inconclusive, however it suggests the need for further research in this area.
There were a number of notable gaps in research and evidence. The area of menopause and post-menopause health in the female military workforce was a clear omission. These issues are important given the increasing numbers and age of the female military workforce, and the likelihood that menopausal and post-menopausal women will remain in the workforce longer. More striking, fertility was only examined in two studies, and only then as a secondary outcome. The dearth of research examining impacts on fertility is surprising, although both gaps could be attributable to the age of the cohort. Most deploying females in the US are relatively young and may not yet have encountered fertility issues or menopause, but these areas will become more significant as increased numbers (and ages) of women deploy in operational roles, and their roles expand. Furthermore, with insufficient data from other countries and differing demographic profiles of servicewomen, it is not possible to determine whether fertility issues exist. Growing evidence of the potential burden of menopause, and the various environmental exposures that may adversely impact fertility, indicates these topics will be extremely relevant into the future. Finally, while post-childbirth health and wellbeing was addressed in the context of mental health, and briefly in relation to physical fitness, there was a distinct absence of research regarding breastfeeding among servicewomen. Given the extent of research focussed on pregnancy outcomes, the lack of studies in the area of post-childbirth health and wellbeing is conspicuous. With an increased drive to retain mothers in the workforce, more research in this area is required.
In addition to examining active service impacts more generally, the studies in this review examined the effects of deployment to the Persian Gulf, Iraq and Afghanistan. It is important to note that, except where otherwise specified, findings related to deployment impacts from one area are not necessarily applicable to other areas. Similarly, where findings are specified for Army, Navy, Air Force or Marines, these may not be transferable to other services. Indeed, a number of studies showed significant service specific differences in health outcomes for servicewomen.
Taken together, this review highlights the limited available research relating to the impacts of military service on the sexual and reproductive health of servicewomen. The majority of reviewed studies fell into NHMRC evidence category III-2 or below including a considerable body of qualitative research. Only four included papers were of evidence category II or above (Controlled trials, with and without randomisation). With the exception of one Australian study, the remainder were from the United States. This disparity reflects the higher numbers of females in the US already in combat and deployed roles, and their increased focus on health surveillance. However, it also highlights issues in terms of generalisability and current gaps in research and understanding relevant to the experience of other countries, including Australia.
Corresponding author: Dr Ellie Lawrence-Wood,
ellie.lawrence-wood@adelaide.edu.au
Authors: E. Lawrence-Wood,1 S. Kumar,2
S Crompvoets,3 B. G. Fosh,4 H. Rahmanian,1
L. Jones,1 S. Neuhaus1
Author Affiliations:
1Centre for Traumatic Stress Studies, University of Adelaide
2School of Health Sciences, International Centre for Allied Health Evidence, University of South Australia,
3Academic Unit of General Practice, The Australian National University
4Flinders University