Do COVID Vaccines Affect the Menstrual Cycle?

Boston University School of Public Health professor Lauren Wise shares an update on her research into whether COVID-19 vaccines impact the menstrual cycle. Wise is the principal investigator of PRESTO, or the Pregnancy Study Online, and in 2021 she was among a group of researchers awarded $1.67 million in funding from the National Institutes of Health to conduct this research. In this episode, Wise shares her initial insights into the research on the COVID vaccine’s potential impact on menstruation and other health outcomes, such as fertility.

You can also read this interview here. 

Transcript

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this is Question of the Week from BU Today. do covid vaccines affect the menstrual cycle? one of our most read articles in 2021 featured a boston university professor who was among a group of researchers awarded funding from the national institutes of health to research whether covid-19 vaccines had any impact on menstruation with over half a million page views the story moved readers who as of this recording have left over 400 passionate comments sharing their experiences given this outpouring of interest we wanted to follow up with school of public health professor of epidemiology Lauren Wise for an update on the research Lauren is the principal investigator of PRESTO or the pregnancy study online which follows women trying to conceive from preconception through six months after birth since 2013 Lauren and the PRESTO team have been collecting data on a range of aspects related to female health and fertility in september 2021 they were one of five teams selected by the NIH to study the impact of coveted vaccines on the menstrual cycle in this episode Lauren shares what her study has found so far i just want to say how surprised i was to see so many comments on the brink about this topic maybe i shouldn't have been so surprised but it's pretty clear that menstruation is a really important health outcome for women and it's great to see so many women talking about this this is typically more of a taboo subject but you know so many women have come out and expressed their experience about menstruation following vaccination and i'm glad that their voices are being heard there have been a lot of anecdotal reports on various social media outlets where women have said after vaccination they've experienced changes in their menstruation such as heavier menses earlier onset of menses or more painful periods but in the clinical trials that came out looking at the effects of vaccination they really just looked at life or death type outcomes and not reproductive outcomes like menstruation or fertility or even pregnancy outcomes so this is a very understudied area of investigation and i'm really happy that the national institutes of health has decided to fund these additional studies looking at the extent to which covert vaccination has an impact on menstruation scientifically you know thinking about why this could be happening i mean i think any agent that triggers an immune response could plausibly influence cellular processes in the uterus and ovaries that could have an impact on menstruation so it kind of is plausible but the extent to which it is you know clinically meaningful whether the the effect might be short-term or long-term or whether really the effect is evident when we compare women who didn't have any changes in their menses we need to make sure that we study them as well and in addition to asking them about you know their lifestyle their behaviors their diet a range of different exposures we also ask them about their menstruation and we also invite them to use a menstrual charting app where they can track lots of information about their menstrual characteristics and in addition to that we were able to add new questions on code vaccination and also COVID infection and also stressors related to the COVID pandemic which plausibly you know confound these associations and so we'll be able to look at the COVID vaccination and changes in menstruation during six cycles of follow-up using multiple sources of data so we have self-reported questionnaire data and then we have the menstrual charting data and some of the outcomes that we're actually interested in that have also come up in some of the anecdotal reports are changes in cycle regularity cycle length intensity of menstrual flow women have reported heavier periods length or duration of the menstrual flow like longer periods and some women have actually reported bleeding between periods so intermenstrual bleeding and then there's pain associated with menses and we have information on vaccine type so the brand we can look at and as i mentioned earlier we can control for lots of additional factors that could explain why you know some women are having these symptoms versus not so like age so there's some reports in perimenopausal women having more symptoms you know COVID infection itself and then just the the sheer number of COVID related stressors like financial insecurity child care problems um you know a range of different stressors and then of course we know that those who received the vaccination earlier tended to have pre-existing health conditions so we need to control for that and finally occupation is another important consideration since PRESTO's inception in 2013 the team has collected self-reported data from thousands of women in doing so they have uncovered new insights into fertility such as how the time of year affects fertility and whether a mother or father's use of marijuana impacts a female's ability to conceive here's Lauren again with more context on the study so PRESTO is a prospective cohort study and we recruit women in the preconception stage so they're actively trying to conceive but they're not pregnant yet and so the goal really is to identify a group of women who have just recently discontinued birth control so they're not using any hormones or any kind of contraception and they're trying to conceive we do um advertise primarily on social media so it's very much an internet-based study where all the recruitment occurs through the internet so we might put an ad on instagram or facebook or twitter and prospective participants will see the ad they'll click on the ad they'll go to the boston university website and they can read more about the study and then they can fill out the consent form if they're interested and then go right to the baseline questionnaire once we confirm their email address so there's this very uh innovative efficient way of recruiting participants and then getting them to fill out this pretty lengthy baseline questionnaire that really asks about you know medical history contraceptive reproductive histories just a range of different behaviors lifestyle factors diet you know use of multivitamins exercise and then what we do is we follow the women forward in time with using shorter questionnaires so every two months they fill out a shorter questionnaire asking whether they've conceived or not and just updating any exposure information that could plausibly change over time so that's what's so much shorter and so important to keep the participants engaged and connected to the study and so they get followed up for up to 12 months or until they conceive whichever comes first and then they can also fill out an early pregnancy questionnaire and a late pregnancy questionnaire if they conceive and then a postpartum questionnaire six months after delivery and what's nice about PRESTO is right after they uh the participants enroll at baseline they are offered a premium menstrual charting app at um kandara.com and so they uh can enter information about you know days of their menstrual cycle characteristics of the menstrual cycle but also like their fertility signs so did they test for ovulation did they look at the cervical the consistency of their cervical mucus did they check for their basal body temperature all of these things can be helpful for identifying the fertile window and helping couples time intercourse to the fertile window and increase their chances of conception so the reason why this cohort was so conducive to doing a study of vaccination and menstruation is that we have the menstrual charting app information we also have all the menstrual characteristics from the baseline questionnaire and from follow-up and these women are not on hormones i mean it's really key one of the things that they put in the request for applications from the nih was that the participants not be using hormones and because all of these women are trying to conceive none of them are on hormones so it seemed like a really good fit so the study is ongoing we are still actively recruiting participants from the united states and canada from all 50 states from all 10 provinces no restrictions and we now have more than 16 000 women who have enrolled since 2013 and we recruit about 3 000 women per year uh in a good year and of course providing provided we have funding from the nih which we are lucky to have and we also recruit their male partners but to a much smaller extent so we have um i want to say nearly 4 000 male partners enrolled and so the study really has not changed its focus this menstruation project is very much like a supplemental side focus and i have to say we've received a lot of emails from people who are interested in the menstrual you know study that we're doing but very few of them have enrolled very few of them are actively trying to conceive so we don't think there's going to be a very large probability that women will enroll in the study because they've been having menstrual problems and they want to be able to contribute to the study in fact we've had to turn a lot of people away who wanted to enroll that being said the prospective design is really helpful because what we do is we only compare women before and after they receive the vaccination so it's not like we're enrolling people who have already had the vaccination and the menstrual changes into our study we would only be looking at their data comparing before the vaccination versus after and so that's a good way to guard against any bias in the reporting of the menstrual factors or the selection of the participants into the study because the study is ongoing we will have the potential to look at effects of the booster shot so we just added today we just added some questions about the booster shots um we had to allow for participants to report a change in the brand so we didn't assume that they have the same type of vaccinations for example pfizer you know you could switch over to moderna and vice versa we didn't make that assumption and we also collect a lot of information on the male partner because we know that for example fever that might be associated with vaccination could have a profound effect on semen quality so we try to get um a full range of information from both partners and perhaps in the future we could look at the effects of the booster on menstruation and also fertility with funding from the NIH wise and the PRESTO team now hope to find out more about potential changes to menstruation falling COVID vaccination Lauren filled us in on what she and the team have seen so far we don't know yet whether vaccination does have an effect on menstruation so i think we need to wait and see what the results of these studies come out with and we also let's just say there is an effect we don't know if it's just a short-term effect or a longer-term effect and so even if we see uh evidence of short-term effects um it may be that these effects go away and are no longer you know clinically meaningful or you know wreaking havoc on women's lives over the long term meaning like six months after vaccination um we also you know need to keep in mind what are the other types of reproductive outcomes of interest like fertility that that being said i can tell you that i was surprised to see how low the percent vaccinated in our cohort was and i think in particular young reproductive age women may be less likely to be getting vaccination against COVID because there's so little known about the effects on their fertility i think that's a really major reason for uh vaccine hesitancy in this population uh and for good reason maybe there's not you know not enough enough research out there on these effects and so we do we do think i think we find about 60 of the women reported vaccination and again this increases with time and we only have gone through um you know follow up through early november but still i think some women are holding out some women are concerned about the anecdotal reports of effects on menstruation some women are concerned about effects on fertility we need to hear that validate the concerns and provide more data that we can use to evaluate the effects of vaccine on health outcomes now that being said i've been vaccinated uh you know everybody on my team has been vaccinated this the centers for disease control and prevention recommends that all individuals age five and above get vaccinated and there's no evidence that the vaccine has any impact on menstruation fertility any of these reproductive outcomes fertility is definitely on our minds because that's like our main outcome variable for this study and i can tell you that we have completed our analyses of fertility and we have a manuscript that's currently under review so pregnancy loss is actually pretty common it's about 20 of all confirmed pregnancies so uh all pregnancies that might be confirmed by a home pregnancy test about 20 of them do result in a loss after that point so it's much more common than scientists initially conceived and there have been two studies that have come out at least showing no effect of COVID vaccination on miscarriage the data have been pretty limited um you know they've been looking at later losses um because they've been using claims databases some of them actually might rely on uh self-reported data from vsafe i don't know if you've heard of the v safe it's basically i when i got my vaccination i actually got invited to participate it's like this link that was sent to me and i just filled it out based on like how i was feeling what are my symptoms and i'd get a questionnaire through my text messages like every i think it was like every week after i was first vaccinated and then it was like every month thereafter that is like a sort of national data set of individuals who did opt in to complete the questionnaires after they were vaccinated and that study also did not find any association between COVID vaccination and miscarriage while PRESTO and other NIH-funded studies continue to track COVID-19 vaccine's impact on menstruation fertility and other health outcomes Lauren and her team of epidemiologists continue to recommend their participants get vaccinated against COVID-19. there's a wealth of information that COVID infection itself has a really negative impact a harmful impact on pregnancy outcomes on birth outcomes and so taking into account all of the available information right now from all the data out there i think the evidence is still weighing um for vaccination it's tough being a researcher in this area because while we recognize the lack of data we also you know as an epidemiologist as trained as an epidemiologist we are strongly encouraging our participants to get vaccinated so again given the biology of what we know about how these vaccines could affect reproductive health given the available evidence and there have been some one study on fertility outcomes very small study that came out last month and then all that data on the negative effects of code infection on pregnancy and birth outcomes we we strongly encourage women to get vaccinated against COVID there's a lot more research out there on the effects of chronic stress and fertility i don't know as much about menstruation but there there's certainly a link between you know the hypothalamic pituitary adrenal axis that produces stress hormones and the hypothalamic pituitary ovarian axis that produces ovarian hormones that are important for menstruation so there is quite a bit of literature on on the connectedness the interrelatedness between those two axes and so uh for sure in PRESTO and many previous studies we have found that higher levels of perceived stress as measured by the perceived stress scale have been associated with reduced fertility and you know that makes a lot of sense so so certainly uh part of the association we're seeing here or you know the anecdotal reports that we're seeing when we when we look at vaccination administration could be driven by increased levels of stress uh related to the COVID pandemic and so it will be very important to control for that and uh yes i would say the evidence to support that is much clearer stress can harm reproduction stress is negatively associated with menstruation we have started uh cleaning the data and taking a look at the distribution of some of the variables that we're interested in like the menstrual characteristics part of the challenge is trying to identify the precise timing of the vaccination relative to each menstrual cycle so we've been doing a lot of additional you know coding and cleaning of the data and so just looking at the first and second doses of you know pfizer moderna and the j j dose the first dose we should be able to produce some results by spring 2022 and be able to look at both short-term and longer-term effects over a six-month period and then if there's any interest in looking at the effects of the booster you know the cdc is recommending that all adults get their booster shots at this point not just specific subgroups you are at higher risk so we would anticipate that as the prevalence of that increases we would be able to start looking at the effects of the booster on menstruation maybe by the summer time we should have some results there or next fall the key thing is to be able to look not only at short-term effects but also long-term effects uh to see if these these um vaccination effects if they do exist if they linger or go away as the PRESTO team continues to analyze the data on COVID vaccination and menstruation Lauren says there's currently no evidence that COVID vaccination has any impact on menstruation she also wanted to express gratitude for her fellow researchers and the PRESTO study participants um i cannot give the actual results at this time but i can tell you that we've already received comments back so we're in the process of revising the manuscript and we will have some really good data probably the best data out there on the extent to which COVID vaccination affects fertility because again we really want to be able to study couples who are actively trying to conceive before they conceive and look at the effect of the vaccination on accountability in a prospective perspective design so i can tell you that there's no evidence currently that COVID vaccination has any negative impact on menstruation fertility pregnancy outcomes birth outcomes so there's no evidence to support any of any of those associations and so i think based on the best available evidence right now it makes good sense for women to get the COVID vaccination particularly because there is much better evidence that COVID infection adversely affects the risk of pregnancy outcomes birth outcomes many many different outcomes including you know morbidity mortality so that's where we're at right now you know science is one of those things that just keeps evolving right there's more and more information that comes out over time as we get more and more data about vaccination and its impact on menstruation fertility miscarriage and other outcomes i'll be able to revise my statement i agree that it's frightening um there's so little that's known we need to validate the feelings that people have you know their fears about vaccination but i can tell you that millions of people have been vaccinated and they're doing just fine and again there's very little reason to think that the vaccine would be harmful to menstruation fertility or any of these other outcomes i feel um obviously very lucky to be in this space and like it's a tremendous opportunity to learn so much more about these understudied health outcomes but i do think in general if you do a search for study you know grants that are funded on like fertility or abortion you know spontaneous abortion or menstruation you will find very very few of them they tend to be very understudied this is a very understudied area of research and so in a way we are lucky that we have um this ongoing supported study of PRESTO and that we have been given the opportunity to develop well-designed questions to ask women about these understudied health outcomes i feel so thankful and grateful to our participants for being willing to share this information with us i don't think these outcomes are particularly easy to share i mean i think they're very sensitive especially pregnancy loss um especially changes in menstruation and so i'm often in awe of the participants who are willing to enroll and and share their um experiences with us so yes just tremendous a tremendous amount of gratitude that we are able to do this research these couples are doing this out of the you know goodness of their hearts you know for altruistic reasons and it really is such a such an amazing thing that they're they're hoping to advance science they're hoping to help other couples you know future couples learn more about how to improve their fertility and how to reduce miscarriage and reduce adverse pregnancy outcomes so yes i love my work i love being in the space um it just it just feels fun and and eye opening and rewarding i mean i just feel like i owe a lot of credit to our wonderful research team and also to boston university for supporting our research you know way before we even got funding from the national institutes of health we you know would apply for seed grants through bu and um you know we have so many students now um at various levels of training um in master's degree program doctoral program um post-doctoral fellows who are actively engaged in the research and just contributing so much to you know collecting the data analyzing the data summarizing the data getting you know disseminating the data and and really it's a team effort it takes a village to do this kind of work and and we are very committed to getting these results and out there for women who are really concerned about you know vaccination and menstruation and fertility and miscarriage um and certainly feel a tremendous sense of responsibility to to get the most accurate data out there in a timely fashion thanks to Lauren Wise for joining us on this episode of question of the week and best of luck to the PRESTO team as they continue this important work i'd also like to give an extra special thanks to former brink editor Kat McAlpine for recording this conversation with Lauren. Kat will miss you and we wish you all the best on your next adventure this episode was edited by bu today executive editor Doug Most and engineered by producer Andy Hallock thanks for listening and see you in two weeks