Episode 18: Covid-19 & Menstruation feat Dr. Kimberlynn Heller
OHA COVID-19 vaccine website: covidvaccine.oregon.gov
OHSU News article
Ask a Black Doctor on The Numberz
Q1: OHSU will be studying data related to COVID-19 and menstruation. Why?
A1: Since the vaccines became available, people have been reporting changes to their
menstrual cycles— For example, getting their period earlier or later than usual, or even
missing a cycle. These types of changes could cause concerns. A missed period could
cause a pregnancy scare for some, or false hope about a potential pregnancy for
For people who have heard about these reports, not knowing how or why their period
may change may be why they haven’t gotten vaccinated yet. To date there have been
no causal link between menstrual changes and COVID-19 vaccines. This study is
designed to provide clarity on this issue.
Q2: How will the study work?
A2: Data will be collected from two apps that track menstrual cycles, Clue and Natural
Cycles. Study questions include:
How long does the period typically last?
How often does it happen and is it regular?
Was it heavier or lighter bleeding?
What changed after getting vaccinated?
This data will then be compared to the control group, that is, unvaccinated women.
Q3: Is this study going to include females of all ages?
A3: Given the consent parameters of the data OHSU is getting – no one under the age
of 18 is included. The primary analysis will be 18-45 as that is the norm for looking at
As women age, menstrual cycle variance becomes a confounder which is why we aren’t
just including everyone until menopause. Another researcher funded by the NIH monies
is looking at adolescents.
Q4: How do race and ethnicity fit into the study?
A4: Individuals of all race/ethnicities are included in this study.
Q5: This study is being done in part to allay concerns about the vaccines, but the
vaccines are still considered safe.
A5: That’s right! We know COVID-19 vaccines are safe and effective. But we also know
that many people want to learn more about the vaccines before deciding to get
vaccinated. There is plenty of anecdotal evidence indicating that menstrual changes, if
any, after vaccination are minimal and self-limited. We also know that Covid-19 illness
will lead to significantly more menstrual disruptions.
Q6: There are also lots of different reasons a period could change, right?
A6: Yes, there are many factors, because the reproductive health system is incredibly
complex. Some of these factors include increased stress, lifestyle changes, dietary
changes, amount of physical activity. Symptomatic infection with the novel coronavirus
is significantly more disruptive to menstruation than the vaccines. It is, however,
theoretically possible that COVID-19 vaccines may cause menstrual changes due to the
Q7: Just last week, it was reported that in the U.K., there were over 30,000 reports
of menstrual changes related to COVID-19 vaccines. So this topic is gaining
It is true that this issue has gained a lot of attention. It is also important to note that
30,000 out of hundreds of millions of vaccinated women is still a tiny fraction. This
highlights how safe and effective these vaccines are even for females who are still
menstruating. These types of reports might lead to decreased vaccine confidence
hence the need to conduct studies such as these.
Q8: Are these types of changes normally studied as a side effect?
A8: No. In general, menstrual changes aren’t really studied in vaccine clinical trials, or in
many areas outside women’s (reproductive) health. The Vaccine Adverse Event
Reporting System (VAERS) has not shown this to be a Covid-19 vaccine side effect.
When experiencing menstrual changes, women often pause and think about their
Am I feeling stressed?
Am I getting enough to eat?
Am I getting enough sleep
Is this something I need to ask my doctor about?