Tag: menstruation

Categories : Obstetrics & GynaecologyTags :

First Menstrual Periods are Arriving Earlier for Younger Generations

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The average age at menarche, the first menstrual period, has been decreasing among younger generations in the US, especially those belonging to racial minorities and lower socioeconomic statuses, according to a new study led by researchers at Harvard T.H. Chan School of Public Health. It also found that the average time it takes for the menstrual cycle to become regular is increasing.

The study, published in JAMA Network Open, is the latest publication from the Apple Women’s Health Study, a longitudinal study of menstrual cycles, gynaecological conditions, and overall women’s health conducted by Harvard Chan School, the National Institute of Environmental Health Sciences, and Apple.

“Our findings can lead to a better understanding of menstrual health across the lifespan and how our lived environment impacts this critical vital sign,” said co-principal investigator Shruthi Mahalingaiah, assistant professor of environmental, reproductive, and women’s health at Harvard Chan School.

While previous studies have shown trends towards earlier menarche over the past five decades, data has been limited on how these trends present within different racial groups and socioeconomic statuses. Additionally, few studies have had sufficient data to identify any trends regarding time to menstrual cycle regularity.

The researchers used the Apple Women’s Health Study’s large, diverse dataset to fill this research gap. The 71 341 participants who enrolled between November 2018 and March 2023 self-reported the age at which they first began menstruating and their race and socioeconomic status. The researchers divided the participants into five age brackets: born between 1950–1969, 1970–1979, 1980–1989, 1990–1999, and 2000-2005. Ages of menarche were defined as early (younger than 11 years old), very early (younger than 9), and late (ages 16 and above). A subset of participants (61 932) self-reported the time it took for their menstrual cycle to become regular and were divided into five categories: up to two years, between three and four years, longer than five years, hasn’t become regular, or became regular with use of hormones. Another subset (9865) provided their body mass index (BMI) at their age of menarche.

The study found that as birth year increased (meaning younger participants), average age at menarche decreased and time from menarche to menstrual cycle regularity increased. Among participants born from 1950–1969, the average age at menarche was 12.5 years, and the rates of early and very early menarche were 8.6% and 0.6%, respectively. Among participants born from 2000–2005, the average age of menarche was 11.9 years, and the rates of early and very early menarche were 15.5% and 1.4%, respectively. Across the two groups, the percentage of participants who reached menstrual cycle regularity within two years of menarche decreased from 76% to 56%. The researchers observed that these trends were present among all sociodemographic groups but were most pronounced among the participants who identified as Black, Hispanic, Asian, or mixed race, and who rated themselves as belonging to a low socioeconomic status.

The findings showed that BMI at age of menarche could explain part of the trend toward periods starting earlier. Other possible factors that might explain the trend include dietary patterns, psychological stress and adverse childhood experiences, and environmental factors such as endocrine-disrupting chemicals and air pollution.

“Continuing to investigate early menarche and its drivers is critical,” said corresponding author Zifan Wang, postdoctoral research fellow in Harvard Chan School’s Department of Environmental Health. “Early menarche is associated with higher risk of adverse health outcomes, such as cardiovascular disease and cancer. To address these health concerns – which our findings suggest may begin to impact more people, with disproportionate impact on already disadvantaged populations – we need much more investment in menstrual health research.”

The authors noted some limitations to the study, including that it relies heavily on retrospective self-reporting.

Source: Harvard T.H. Chan School of Public Health

Categories : GenderTags :

Women’s Mental Agility is Better During Their Periods

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Photo by Ashley Williams

New research involving female football players has shown that they react more quickly and accurately during their periods, despite them feeling that they perform worse. The study, published in Neuropsychologia, is the first to assess sport-related cognition during the menstrual cycle and is part of a larger research project supported by the FIFA Research Scholarship.

The findings, from University College London, act as a proof-of-principle that specific types of cognition fluctuate throughout the menstrual cycle, which could have implications for injury and other aspects of women’s health.

Previous sports medicine research has shown that women seem to be at greater risk of sport-related injury during the luteal phase, which is the time between ovulation and menstruation. This is possibly related to the significant hormonal changes that occur throughout the menstrual cycle. But precisely how these changes are linked to an increased likelihood of injury are unknown at present.

In this study, researchers at UCL and ISEH collected reaction time and error data from 241 participants who completed a battery of cognitive tests 14 days apart. Participants also completed a mood scale and a symptom questionnaire twice. Period-tracking apps were used to estimate which phase of their cycle the participants were in when they took the tests.

The tests were designed to mimic mental processes that are typical in team sports. In one test, participants were shown smiling or winking faces and asked to press the space bar only when they saw a smiley face, to test inhibition, attention, reaction time and accuracy. In another, they were asked to identify mirror images in a 3D rotation task, which assesses spatial cognition. A task that asked them to click when two moving balls collide on screen measured spatial timing.

Though participants reported feeling worse during menstruation and perceived that this negatively impacted their performance, their reaction times were faster and they made fewer errors. For example, their timing was on average 10 milliseconds (12%) more accurate in the moving balls task, and they pressed the space bar at the wrong time 25% less in the inhibition task.

Participants’ reaction times were slower during the luteal phase, which begins after ovulation and lasts between 12–14 days up to the beginning of menstruation. They were on average 10–20 milliseconds slower compared to being in any other phase, but their error rate was unchanged.

Dr Flaminia Ronca, first author of the study from UCL Division of Surgery and Interventional Science and ISEH, said: “Research suggests that female athletes are more likely to sustain certain types of sports injuries during the luteal phase and the assumption has been that this is due to biomechanical changes as a result of hormonal variation. But I wasn’t convinced that physical changes alone could explain this association.

“Given that progesterone has an inhibitory effect on the cerebral cortex and oestrogen stimulates it, making us react slower or faster, we wondered if injuries could be a result of a change in athletes’ timing of movements throughout the cycle.

“What is surprising is that the participant’s performance was better when they were on their period, which challenges what women, and perhaps society more generally, assume about their abilities at this particular time of the month.

“I hope that this will provide the basis for positive conversations between coaches and athletes about perceptions and performance: how we feel doesn’t always reflect how we perform.”

To put the findings in context, the authors say the fluctuation in timing could be the difference between an injury or not. Previous research has shown that a variation of just 10 milliseconds can mean the difference between a concussion and a lesser injury, for example. In the colliding balls task, participants’ timing was on average 12 milliseconds slower during the luteal phase compared to every other phase, a difference of 16%.

Dr Megan Lowery, an author of the study from UCL Surgery & Interventional Science and ISEH, said: “There’s lots of anecdotal evidence from women that they might feel clumsy just before ovulation, for example, which is supported by our findings here. My hope is that if women understand how their brains and bodies change during the month, it will help them to adapt.

“Though there’s a lot more research needed in this area, these findings are an important first step towards understanding how women’s cognition affects their athletic performance at different points during their cycle, which will hopefully facilitate positive conversations between coaches and athletes around performance and wellbeing.”

Professor Paul Burgess, senior author of the study from UCL’s Institute of Cognitive Neuroscience, said: “This study emerged from listening carefully to female soccer players and their coaches. We created bespoke cognitive tests to try to mimic the demands made upon the brain at the points in the game where they were telling us that injuries and problems of timing occur at certain times of the menstrual cycle.

“As suggested by what the soccer players had told us, the data suggested that women who menstruate – whether they are athletes or not – do tend to vary in their performance at certain stages of the cycle. As a neuroscientist, I am amazed that we don’t already know more about this, and hope that our study will help motivate increasing interest in this vital aspect of sports medicine.”

Source: University College London

Categories : Injury & Trauma Obstetrics & GynaecologyTags :

Menstrual Cycle Phases Linked to Increased Injury Risk for Female Athletes

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Photo by Ashley Williams

Football players in England’s top-tier WSL were six times more likely to experience a muscle injury in the days leading up to their period compared to when they were on their period, according to a new study published in Medicine & Science in Sports & Exercise.

This the first prospective longitudinal study monitoring menstrual cycles alongside injuries in female footballers. The findings suggest there could be increased injury risk windows at particular times in the cycle.

Despite being a relatively small sample size, the data demonstrates the need to consider the menstrual cycle in elite sports, to reduce injury risk and to support the wellbeing of athletes.

Menstrual cycle symptoms are common and around two thirds of elite athletes feel that these can have negative impacts on their performance. There has been little previous research tracking injuries alongside the menstrual cycle in female sport, despite much speculation and anecdotal evidence suggesting that there may be some key times for increased injury risk. Given the increased professionalism, interest, growth, and investment in women’s sport, the authors say further research in this area is needed.

In this study, researchers at UCL and the University of Bath recorded time-loss injuries and menstrual cycle data for elite female football players across three seasons. All of the players were based at one Women’s Super League (WSL) club, the top tier of women’s football in England. During the study they tracked 593 cycles across 13 390 days, in which time 26 players experienced 74 injuries.

The authors divided each cycle into four main phases in their study. Each phase comes with assumed hormonal changes that have the potential to influence different aspects of a woman’s health and wellbeing.

Ally Barlow, first author of the study from the University of Bath and a physiotherapist at the WSL club, said: “We have been tracking player’s menstrual cycles for a number of seasons to observe trends in terms of symptoms and cycle characteristics. We were interested to learn more about the potential association between injury risk across the menstrual cycle. This study set out to collect specific scientific data so that we could learn more about the menstrual cycle and player’s injury risk.”

Analysis of the data found that players were six times more likely in the pre-menstrual phase (oestrogen and progesterone decrease to bring about the onset of menstruation) and five times more likely in the early-mid luteal phase (after ovulation when both oestrogen and progesterone are assumed to increase and remain high) to experience a muscle injury, compared to when they were in the menstrual phase.

Dr Georgie Bruinvels, senior author of the study from UCL Surgery & Interventional Science and the Institute of Sport, Exercise & Health (ISEH), said: “While these results must be viewed with caution, this data highlights a need to investigate this area further. Given the growth of women’s sport it’s an exciting time to be working in female physiology, but there are a number of known challenges when conducting research with female athletes, in part explaining why there is such a significant sex data gap.

“Conducting large-scale research is complex but must be prioritised to best support female athletes, and we hope studies like this will pave the way for this. Every woman has their own unique physiology, so it’s crucial to support and empower them in the right ways. If future research demonstrates that there are risk windows for certain injury types, we should be proactive in mitigating these risks to enable female athletes to exercise and compete on any given day.”

The authors emphasise that further data collected in a standardised manner is needed before the sports science community can start to look for biological explanations for this increased injury risk.

Dr Jo Blodgett, an author of the study from UCL Surgery & Interventional Science and the Institute of Sport, Exercise & Health (ISEH), said: “Though our sample size for this research was relatively small, we observed clear links between cycle phase and injury prevalence, and the size of the association – six times higher in the premenstrual phase and five times higher in the early-mid luteal phase for muscular injuries – was quite large.

“To better understand the variability in injury risk across the cycle we need more players and teams to continually track injury incidence, menstrual cycle and symptoms in a standardised manner. At the elite level, injuries to your squad can mean the difference between winning and losing, the difference between being crowned champions and runners-up. But perhaps more importantly, it means pain and suffering for players that could perhaps be avoided with better player-centred support.”

Source: University College London

Categories : Obstetrics & Gynaecology Pain ManagementTags :

A Third of Women Experience Migraines Associated with Menstruation

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Of the nearly 20 million women who participated in a U.S. national health survey, one-third reported migraines during menstruation. The analysis was conducted by researchers at Georgetown University Medical Center and Pfizer, Inc., which makes a migraine medication.

Because of the underuse of medications to help treat or prevent menstrual migraines, investigators wanted to understand how common menstrual migraines were and which groups of women could most benefit from potential therapies. The study, presented April 16, at the American Academy of Neurology 2024 Annual Meeting in Denver, also revealed the most common medications taken by those women seeking to prevent menstrual migraines.

“The first step in helping a woman with menstrual migraine is making a diagnosis; the second part is prescribing a treatment; and the third part is finding treatments patients are satisfied with and remain on to reduce disability and improve quality of life,” says the study author, Jessica Ailani, MD, professor of clinical neurology at Georgetown University School of Medicine.

The researchers used the 2021 U.S. National Health and Wellness Survey to analyse responses from women who reported their current migraine treatments, frequency and disabilities via the Migraine Disability Assessment Test (MIDAS), a five-question survey. A migraine headache can cause severe throbbing pain or a pulsing sensation, usually on one side of the head. It’s often accompanied by nausea, vomiting, and extreme sensitivity to light and sound.

“Discrepancies in the incidence of who gets migraine attacks associated with menses is likely due to premenopausal women having more regular menstrual cycles and thus more menstrual-related migraines,” says Ailani, also director of the MedStar Georgetown Headache Center at Medstar Georgetown University Hospital. “Additionally, as women move into their 40’s and become peri-menopausal, there tends to be a greater shift through the month in hormone levels also leading to frequent migraine attacks.”

The survey found that for all women during their menstrual periods, migraine attacks occurred as frequently as 4.5 times and that monthly only migraine headaches lasted 8.4 days, on average; 56.2 % of women had moderate-to-severe migraine-specific disabilities that ranked highest on the MIDAS scale.

When looking at treatments women in the survey used to help control their migraine symptoms, 42.4% used over-the-counter medications while 48.6% used prescription medications. Of the 63.9 % of women who used migraine treatments for acute symptoms, the most commonly used were triptans, a class of drugs developed in the 1990s to quiet overactive nerves associated with migraines and cluster headaches.

Sara’s story

Sara, a 38 year old mother of two, says her migraines are predictably and consistently worse during her period.

“It definitely disrupts my ability to go about my normal activities including at work,” Sara says. “I’m pretty lucky that I’m generally responsive to prescription medication, but I often still have to lie down for an hour or so while the medicine kicks in.”

Sara is being treated preventatively for migraines with Botox. She says over the past couple of months, she’s had a couple of migraines outside of when she gets her period, but that the headaches are definitely worse during menstruation.

“While I had my last period, I had a migraine every day for a week,” Sara says. “It’s starkly different [during menstruation].”

Prevention possibilities

Non-steroidal anti-inflammatory drugs (NSAIDs) are sometimes used as preventive medications for women with regular menstrual periods. In this study, 21.1% of women reported use of any migraine prevention medications or therapies.

“Preventive treatments are used less frequently than acute treatment for migraine,” Alaini said. “In my opinion, this is because preventive therapy is a long-term commitment by both a woman and her clinician to improving the disease process. Migraine is a life-long brain disease without a cure, and the goal of preventive therapy is to reduce disease burden and improve quality of life. Unfortunately, newer disease-specific treatments are costly, so generic older treatments are often used and come with greater side effects.”

Next steps

The researcher’s next steps involve looking at larger databases to see if they can mimic findings on a global scale. They want to determine if women with menstrual-related migraine are frequently turning to non-migraine treatments as was seen in around 53% of their current study group.

“As a headache specialist in the U.S., I know I can do better for women in my clinic, but what can be done for the millions of women who don’t get into a headache clinic? That is our true next step,” says Ailani. “If you have migraines related to your menstrual cycle, discuss this with your gynaecologist or neurologist. There are treatments that can help and if the first treatment tried does not work, do not give up.”

Source: Georgetown University Medical Center

Categories : Gender NeurologyTags :

Lower Oestrogen Levels may Explain Migraine Increase During Menstruation

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New research published in Neurology may explain why migraine attacks are more common during menstruation. The researchers found that, as oestrogen levels fluctuate, for female migraine sufferers, levels of the protein calcitonin gene-related peptide (CGRP) that plays a key role in starting the migraine process also fluctuate.

“This elevated level of CGRP following hormonal fluctuations could help to explain why migraine attacks are more likely during menstruation and why migraine attacks gradually decline after menopause,” said study author Bianca Raffaelli, MD, of Charité – Universitätsmedizin Berlin. “These results need to be confirmed with larger studies, but we’re hopeful that they will help us better understand the migraine process.”

The matched cohort study involved three groups of female participants with episodic migraine, all with least three days with migraine in the month before the study. The groups were those with a regular menstrual cycle, those taking oral contraceptives, and those who had gone through menopause. Each group had 30 people, for a total of 180, and were age-matched to women without migraine history.

Researchers collected blood and tear fluid to determine CGRP levels. In those with regular menstrual cycles, the samples were taken during menstruation when oestrogen levels are low and around the time of ovulation, when levels are the highest. In those taking oral contraceptives, samples were taken during the hormone-free time and the hormone-intake time. Samples were taken once from postmenopausal participants at a random time.

The study found that female participants with migraine and a regular menstrual cycle had higher CGRP concentrations during menstruation than those without migraine. Those with migraine had blood levels of 5.95 picograms per millilitre (pg/ml) compared to 4.61pg/ml for those without migraine. For tear fluid, those with migraine had 1.20ng/ml compared to 0.4ng/ml for those without migraine.

In contrast, those taking oral contraceptives or were postmenopausal had similar CGRP levels in the migraine and non-migraine groups.

“The study also suggests that measuring CGRP levels through tear fluid is feasible and warrants further investigation, as accurate measurement in the blood is challenging due to its very short half-life,” Raffaelli said. “This method is still exploratory, but it is non-invasive.”

Raffaelli noted that while hormone levels were taken around the time of ovulation, they may not have been taken exactly on the day of ovulation, so the fluctuations in oestrogen levels may not be fully reflected.

Source: American Academy of Neurology

Categories : Obstetrics & GynaecologyTags :

Premenstrual Anxiety, Mood Swings Amount to a Public Health Issue

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With more than 64% of women suffering from premenstrual mood swings and anxiety, they represent a “key public health issue globally,” according to a new study in Archives of Women’s Mental Health.

The UVA Health study found that most women have premenstrual symptoms every menstrual cycle, with one of the most common symptoms, regardless of age, being mood swings or anxiety. At least 61% of women in all age groups surveyed reported mood-related symptoms every menstrual cycle, which the researchers say suggests “that premenstrual mood symptoms are a key public health issue globally.”

“Our study demonstrates that premenstrual mood symptoms are incredibly common worldwide,” said senior author Jennifer L Payne, MD. “More important, a majority of women reported that their premenstrual symptoms interfered with their everyday life at least some of the time.”

Better understanding premenstrual symptoms

To better understand the type of premenstrual symptoms women experience and how those symptoms affect their daily lives, the researchers analysed more than 238 000 survey responses from women ages 18–55 from 140 countries on the Flo app, which helps women track their menstrual cycle or track their mood or physical symptoms during and after pregnancy.

Food cravings topped the most common symptoms (85.28%), followed by mood swings or anxiety (64.18%) and fatigue (57.3%). Among the study respondents, 28.61% said their premenstrual symptoms interfered with their everyday life during every menstrual cycle, while an additional 34.84% said their premenstrual symptoms interfered with their everyday life sometimes.

“The incidence of reported premenstrual mood and anxiety symptoms varied significantly by country from a low of 35.1% in Congo to a high of 68.6% in Egypt,” Payne said. “Understanding whether differences in biology or culture underlie the country level rates will be an important future research direction.”

A group of symptoms — absentmindedness, low libido, sleep changes, gastrointestinal symptoms, weight gain, headaches, sweating or hot flashes, fatigue, hair changes, rashes and swelling — was significantly more frequent among older survey respondents, the researchers found. The increase in physical symptoms among older survey respondents “makes sense,” the researchers said, as many of these symptoms are associated with perimenopause, a transition period to menopause marked by irregular menstrual cycles.

Payne is hopeful that this survey data will help women get better care by making healthcare providers more aware of the frequency of these symptoms, especially anxiety and mood-related symptoms.

“There are a number of treatment strategies that are available to treat premenstrual symptoms that interfere with a woman’s every day functioning,” she said. “Increasing awareness of how common these symptoms are, and that if they impact functioning that there are treatments available, will help women improve their quality of life.”

Source: University of Virginia Health System

Categories : Ethics and LawTags :

Medical Bodies Push Back against Commission for Gender Equality’s Statement

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The South African Medical Research Council (SAMRC), along with other professional medical and scientific institutions released a statement  distancing themselves from the Commission for Gender Equality’s (CGE) press release of 16 January, 2022, titled “Warning Against Imposing Mandatory Covid-19 Vaccination on Employees and Students”. [PDF]

The CGE cited an article published in Obstetrics and Gynaecology which found that women receiving Pfizer-BioNTech, Moderna or J&J COVID vaccines, vaccine administration was associated with less than a one-day change in cycle length for both vaccine-dose cycles compared with pre-vaccine cycles. The article concluded that clinically meaningful change in menstrual cycle duration associated with COVID vaccination was found. 

The CGE used this study as justification, cautioning businesses and institutions against mandatory vaccination and recommended against sanctions for employees who chose to remain vaccinated.

The signatories expressed their concern at the contents of the statement which is at odds with the scientific understanding of COVID vaccinations, a concern which is compounded by the “enormous influence” of the GCE.

They accept that the vaccine mandates are subject to legal scrutiny, but take issue with the commission “trying to bolster its argument by wrongly insinuating that COVID vaccination has the potential to harm women’s health.”

They also point out that the commission seems to disregard the much greater risks to women and their unborn babies of COVID infection, while misinterpreting evidence on minor menstrual cycle lengthening. This creates fear and confusion in vaccinated women, and may increase vaccine hesitancy.

“It fails to appreciate that one in six unvaccinated pregnant women admitted to hospital in South Africa with COVID infection requires mechanical ventilation, and one in 16 has a fatal outcome,” the signatories stated.

They noted that COVID vaccination provides upwards of 80% protection against severe disease, hospitalisation and death.

They endorse the view of the College of Obstetricians and Gynaecologists of South Africa, which draws on research of the highest quality, that the menstrual effects are minor.

The evidence is “indisputable” that COVID vaccination is safe, does not negatively affect women’s bodies and saves the lives of women, they stress. Statements to the contrary are strongly repudiated.

“We are of the view that the CGE, like all state institutions, medical and scientific bodies, social partners and civil society formations working in the fields of women’s rights, empowerment and equality, should urge women to get vaccinated and advance and defend their rights to all relevant information about and access to vaccination.”

The signatories call on the CGE to withdraw its 16 January statement and to share with it scientific facts on COVID vaccination and women’s health.

Source: South African Medical Research Council

Categories : COVID Obstetrics & GynaecologyTags :

Post-COVID Vaccination Menstrual Changes Investigated

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A paper awaiting peer review on the MedRxiv preprint server shows that menstrual changes in women receiving after the COVID vaccine are quite common.

Many people began sharing that they experienced unexpected menstrual bleeding after being vaccinated for COVID, an emerging phenomenon which was undeniable yet understudied.

Unfortunately, dismissal by medical experts fueled greater concerns, as both vaccine hesitant and anti-vaccine individuals and organisations began to conflate the possibility of short-term menstrual changes with long-term harms to fertility. Many influencers used this well-used framing of protecting women as a means of further anti-vaccine messages.

There are many plausible biological mechanisms that could explain a relationship between an acute immune challenge such as a vaccine, its corresponding and well-known systemic effects on haemostasis and inflammation, and menstrual repair mechanisms of the uterus. The uterine reproductive system is flexible and adaptable in the face of stressors. Examples include marathon running having short term influence on hormone concentrations in the short term; short-term calorie restriction that results in a loss of menstrual cycling can be overcome by resuming normal feeding; that inflammation influences ovarian hormones; and that psychosocial stressors can correspond to cycle irregularity and yet resilience can buffer one from these harms. Typhoid, Hepatitis B, HPV vaccines have all had menstrual irregularity associated with them.  

While sustained early stressors can influence adult hormone concentrations, short-term stressors resolve and do not produce long-term effects. This is quite different from the sustained immune assault of COVID itself: studies and anecdotal reports are already demonstrating that menstrual function may be disrupted long-term, particularly in those with long COVID.

In this sample, 42% of people with regular menstrual cycles bled more heavily than usual, while 44% reported no change, after being vaccinated. Among people who typically do not menstruate, 71% of people on long-acting reversible contraceptives, 39% of people on gender-affirming hormones, and 66% of post-menopausal people reported breakthrough bleeding. We found increased/breakthrough bleeding was significantly associated with age, other vaccine side effects such as fever or fatigue, history of pregnancy or birth, and ethnicity.

Many respondents who had post-vaccine changes did not have them until fourteen days or longer post-inoculation, which extends beyond the typical seven days of adverse symptom reporting in vaccine trials.

Source: MedRxiv

Categories : COVID Obstetrics & GynaecologyTags :

Menstrual Changes After COVID Vaccinations

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In an article in the BMJ, authors argue that menstrual changes after COVID vaccination are plausible and should be investigated. 

Listed common side effects of COVID vaccination include a sore arm, fever, fatigue, and myalgia. However, changes to periods and unexpected vaginal bleeding are not listed, and primary care clinicians and those in the reproductive health field are seeing more and more people who have experienced these events shortly after vaccination.

More than 30 000 reports of these events had been made to the UK;s surveillance scheme for adverse drug reactions by 2 September 2021, across all COVID vaccines currently offered.

Most post-vaccination changes to periods return to normal, and there is no evidence that COVID vaccination adversely affects fertility. In clinical trials, there were similar rates for unintended pregnancies in vaccinated and unvaccinated groups. In fertility clinics, fertility measures and pregnancy rates are similar in vaccinated and unvaccinated patients. The UK’s Medicines and Healthcare Products Regulatory Agency (MHRA) says that there are few reported that 

Menstrual changes have been reported after both mRNA and adenovirus vectored COVID vaccines, suggesting that, if there is a connection, it is likely to be a result of the immune response to vaccination rather than a specific vaccine component. Human papillomavirus (HPV) vaccinations have also been associated with menstrual changes. Indeed, the menstrual cycle can be affected by immune activation from various stimuli, including viral infection: one study found about a quarter of menstruating women with COVID experienced menstrual disruption.

Biologically plausible mechanisms linking immune stimulation with menstrual changes include immunological influences on the hormones driving the menstrual cycle or effects mediated by immune cells in the lining of the uterus, which are involved in the cyclical build-up and breakdown of this tissue. Research may also help understand the mechanism.

Though the period changes are short lived, there is need for adequate research. Vaccine hesitancy among young women is largely driven by false claims that COVID vaccines could harm their chances of future pregnancy. Failing to thoroughly investigate reports of menstrual changes after vaccination is likely to fuel these fears. If a link between vaccination and menstrual changes is confirmed, this information will allow people to plan for potentially altered cycles. Clear and trusted information is particularly important for those who rely on being able to predict their menstrual cycles to either achieve or avoid pregnancy.

In terms of management, the Royal College of Obstetricians and Gynaecologists and the MHRA recommend that anyone reporting a change in periods persisting over several cycles, or new vaginal bleeding after the menopause, should be managed according to the usual clinical guidelines for these conditions.

The authors conclude by stating there is an important lesson in that the effects of medical interventions on menstruation should not be an afterthought in future research. In clinical trials, participants are unlikely to report changes to periods unless specifically asked, so in future trials, information about menstrual cycles and other vaginal bleeding should be actively solicited.

Source: The BMJ