Why is reproductive health important in ME/CFS?
Reproductive health is a state of complete social, mental and physical well-being relating to the functions and processes of the reproductive system. This includes the ability to make informed decisions around family planning, contraception and fertility, and is important for both males and females.
Existing research has shown that ME/CFS is more common in women than men – a situation not unique to ME/CFS as this disparity has also been observed for other illnesses.
Previous evidence suggests that the difference in the number of cases of ME/CFS between men and women may, in part, be related to sex hormones and female reproductive events including menstruation, pregnancy and menopause.
A study from Norway, including 5,809 people with ME/CFS, identified two age groups where the number of new cases of ME/CFS was highest:
- For males, this was 10–19 years.
- For females, this was 10–19 years, and 30–39 years.
These age ranges are important in reproductive health because they include periods of considerable and rapid change in sex hormones. The 10–19 year age group usually includes puberty for both males and females, and the 30–39 age range often includes pregnancy and postpartum period for females.
What does the existing evidence tell us?
While there are currently no published systematic reviews that focus solely on reproductive health in ME/CFS, a recent literature review paper, which focused on long COVID and female reproductive health, also summarises evidence for other conditions, including ME/CFS. Unfortunately, no such studies appear to exist studying male reproductive health.
The research available relating to women with ME/CFS suggests that there may be higher rates of:
- Irregular periods, where the number of days between periods (the length of the menstrual cycle) keeps changing.
- Heavy periods, which can impact on quality of life and lead to absence from school and work.
- Stopped periods.
- Bleeding between periods.
- Endometriosis where cells, similar to those in the lining of the womb, grow in other places, for example the ovaries and fallopian tubes. Symptoms include pain and difficulty getting pregnant.
- Polycystic ovary syndrome, which causes irregular periods and high levels of male hormones in the body, and can lead to difficulties getting pregnant.
- Formation of fluid-filled sacs in the ovaries called ovarian cysts.
- Pelvic pain not related to periods (non-menstrual pelvic pain).
- Early menopause (when periods stop before the age of 45 years).
The review also found that hormonal events, including menstruation, pregnancy and menopause, may act as a trigger for, influence the symptoms of, and alter the course of these illnesses.
Evidence in the review paper suggested that for females with ME/CFS:
- Hormonal changes during the menstrual cycle, particularly prior to menstruation, perimenopause, menopause and post-menopause, may all exacerbate symptoms, or act as a trigger for disease.
- Pregnancy may also act as a trigger for, or increase the risk of developing the disease in the future.
- Evidence on the impact of pregnancy on symptoms is less clear; for some people symptoms improved, while others found they stayed the same, or even got worse.
What are the limitations of the evidence?
While the authors of the review paper did not carry out a systematic search of the evidence (where scientific databases are searched using specific terms to identify all the literature relating to a particular research question), they did find that female reproductive health is an under-researched area for each of the illnesses investigated.
In addition, they concluded that the research studies included in the review were limited by:
- Small sample sizes, which may mean that the studies were unable to detect a significant difference using statistics, even where there was one.
- By a lack of a relevant or healthy control group, which means that it is unclear whether a particular observation would be different in a healthy or control population.
- By the study designs used, which were cross-sectional studies and case reports.
- Cross-sectional studies provide an insight at one point in time, but do not allow for inferences to be made over time.
- Case studies provide detailed information on one person (sometimes a group of people or an event), but results may not be relevant to an entire population.
The authors suggest that it is possible that these limitations are, in part, explained by the historic underfunding of ME/CFS and associated illnesses.
Future research areas
Without more research, it is impossible to draw conclusions about the associations between ME/CFS and reproductive health.
The review paper highlights a number of research priorities for female reproductive health in long COVID, ME/CFS, POTS and EDS. These are:
- How menstruation, pregnancy, sexual function and menopause are impacted by and impact these diseases.
- Sex differences, and the role of sex hormones in the mechanisms of these diseases and their trajectories.
- Research including underrepresented and marginalised groups.
- Rates and mechanisms of reproductive health conditions.
- This article did not consider the reproductive health impacts of long COVID, ME/CFS, POTS and EDS in men.
Summary
For such an important component of most people’s lives, evidence related to reproductive health and ME/CFS is limited – particularly in men. It is vital that good quality research into reproductive health, and the relationship with ME/CFS including mechanisms and disease trajectories is continued for women, and that issues are also researched for men. Without this evidence, it is impossible for medical professionals to be able to offer evidence-based advice to those with ME/CFS around reproductive health issues.
