Hormonal contraceptive prescriptions in the UK Armed Forces

Effect of Menstrual Cycle and Hormonal Contraception on Musculoskeletal Health and Performance: Protocol for a Prospective Cohort Design and Cross-Sectional Comparison

BACKGROUND

Women of reproductive age experience cyclical variation in the female sex steroid hormones 17β-estradiol and progesterone during the menstrual cycle that is attenuated by some hormonal contraceptives. Estrogens perform a primary function in sexual development and reproduction but have nonreproductive effects on bone, muscle, and sinew tissues (ie, ligaments and tendons), which may influence injury risk and physical performance.

OBJECTIVE

The purpose of the study is to understand the effect of the menstrual cycle and hormonal contraceptive use on bone and calcium metabolism, and musculoskeletal health and performance.

METHODS

A total of 5 cohorts of physically active women (aged 18-40 years) will be recruited to participate: eumenorrheic, nonhormonal contraceptive users (n=20); combined oral contraceptive pill (COCP) users (n=20); hormonal implant users (n=20); hormonal intrauterine system users (n=20); and hormonal injection users (n=20). Participants must have been using the COCP and implant for at least 1 year and the intrauterine system and injection for at least 2 years. First-void urine samples and fasted blood samples will be collected for biochemical analysis of calcium and bone metabolism, hormones, and metabolic markers. Knee extensor and flexor strength will be measured using an isometric dynamometer, and lower limb tendon and stiffness, tone, and elasticity will be measured using a Myoton device. Functional movement will be assessed using a single-leg drop to assess the frontal plane projection angle and the qualitative assessment of single leg loading. Bone density and macro- and microstructure will be measured using ultrasound, dual-energy x-ray absorptiometry, and high-resolution peripheral quantitative computed tomography. Skeletal material properties will be estimated from reference point indentation, performed on the flat surface of the medial tibia diaphysis. Body composition will be assessed by dual-energy x-ray absorptiometry. The differences in outcome measures between the hormonal contraceptive groups will be analyzed in a one-way between-group analysis of covariance. Within the eumenorrheic group, the influence of the menstrual cycle on outcome measures will be assessed using a linear mixed effects model. Within the COCP group, differences across 2 time points will be analyzed using the paired-samples 2-tailed t test.

RESULTS

The research was funded in January 2020, and data collection started in January 2022, with a projected data collection completion date of August 2024. The number of participants who have consented at the point of manuscript submission is 66. It is expected that all data analysis will be completed and results published by the end of 2024.

CONCLUSIONS

Understanding the effects of the menstrual cycle and hormonal contraception on musculoskeletal health and performance will inform contraceptive choices for physically active women to manage injury risk.

TRIAL REGISTRATION

ClinicalTrials.gov NCT05587920; https://classic.clinicaltrials.gov/ct2/show/NCT05587920.

INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID)

DERR1-10.2196/50542.

Current risks factors and emerging biomarkers for bone stress injuries in military personnel

INTRODUCTION

Bone stress injuries (BSIs) have plagued the military for over 150 years; they afflict around 5 to 10% of military recruits, more so in women, and continue to place a medical and financial burden on defence. While the tibia generally adapts to the rigours of basic military training, the putative mechanisms for bone maladaptation are still unclear.

METHODS

This paper provides a review of the published literature on current risk factors and emerging biomarkers for BSIs in military personnel; the potential for biochemical markers of bone metabolism to monitor the response to military training; and, the association of novel biochemical 'exerkines' with bone health.

RESULTS

The primary risk factor for BSI in military (and athletic) populations is too much training, too soon. Appropriate physical preparation before training will likely be most protective, but routine biomarkers will not yet identify those at risk. Nutritional interventions will support a bone anabolic response to training, but exposure to stress, sleep loss, and medication is likely harmful to bone. Monitoring physiology using wearables-ovulation, sleep and stress-offer potential to inform prevention strategies.

CONCLUSIONS

The risk factors for BSIs are well described, but their aetiology is very complex particularly in the multi-stressor military environment. Our understanding of the skeletal responses to military training is improving as technology advances, and potential biomarkers are constantly emerging, but sophisticated and integrated approaches to prevention of BSI are warranted.

Being a woman, being a soldier, being a mother: a qualitative analysis of perceptions of pregnancy on working lives of women in the Spanish Armed Forces

INTRODUCTION

Thirty-two years after Spain first allowed women to join the armed forces, 12% of active troops are women, although there are no data on how many of them are mothers. There is a lack of research related to the impact of motherhood on their careers and the challenges they face as well. Previous quantitative research, within North Atlantic Treaty Organization (NATO) forces, has focused on the increased vulnerability and reduced performance of women returning to service after childbirth. However, no study to date has examined the narratives of these women.

METHODS

A qualitative, cross-sectional study was carried out by means of individual interviews which were subsequently analysed employing the interpretative approach of hermeneutic phenomenology. All the interviews were conducted by videoconference, being recorded for subsequent transcription and analysis with MAXQDA v.2018.

RESULTS

Servicewoman reported experiencing fear of informing their command chain of their pregnancy. Many women described feelings of constantly having to prove their worth, and thus perceived the physical restrictions associated with pregnancy and/or postpartum as a threat to their previous achievements. This sometimes led to behaviours that posed a risk to the health of mothers and babies, or eventually resulted in both acute and chronic conditions.

CONCLUSIONS

Some restrictions put in place to protect them during their pregnancies become a source of additional anxiety. Returning to active service, we found that women's desire to fulfil their duties can cause long-term damage to their physical and psychological health. The attitudes servicewomen perceive towards pregnant women and mothers seems to exert a strong influence on the risks they are willing to assume. Understanding and addressing the needs of servicewomen after childbirth, either now, as active members of the Armed Forces, or in the foreseeable future, as veterans, is crucial to both military and civilian healthcare providers.