Annette Riedl is a picture alliance.
A new study using data from the birth control app Natural Cycles shows that a small change to the menstrual cycle is only associated with getting a COVID-19 vaccine. The study follows reports of heavier and longer periods from people who had recently been vaccinations.
Alison Edelman is a professor at Oregon Health and Science University and the author of a study on the topic. Patients reporting that they experienced something is also validation.
The side effect of COVID-19 vaccination was always heavier periods. Stress on the immune system can affect the menstrual cycle, but that doesn't mean fertility is affected. The vaccine doesn't affect fertility or pregnancies. The National Institutes of Health put out a call for research proposals that could look into the question of impacts on periods. The National Institute of Health wanted analysis to be done quickly so that it could look at menstrual cycles from both before and after vaccinations.
Period tracking apps were used as a source of data. Her team talked with Natural Cycles and Clue. She says that data from Clue will likely be included in future studies. The data these apps give is a treasure trove. People who use the apps can agree to let their period tracking information be used for research, and Natural Cycles had already been asking users about vaccinations.
This is the best data that we can get for something like this, unless they included the question in the vaccine trials themselves.
The Natural Cycles study included information on six consecutive menstrual cycles from nearly 4,000 people in the United States. There was no change in the length of people's periods. The length of time between periods after getting their vaccine increased by less than one day compared to the three previous cycles. A small group of people in the study who got both doses of a vaccine within the same cycle were more likely to have a longer increase in their cycle. The length went back to normal after two cycles. Any variation in cycle length is considered normal.
The data from the United Kingdom is consistent with the findings of the current study.
The team is looking at the data on the heaviness of people's periods after vaccination. They plan to look at the data from other countries. The data from the studies on menstrual cycles and the COVID-19 vaccine should be published soon, she says.
The first set of data gives doctors and patients a good idea of what to expect after getting the vaccine. It is now possible to tell people that there is a chance that they might have a slight change in their menstrual cycle length. It looks like it is only temporary.
