1. BBC. Covid vaccine: period changes could be a short-term side effect. BBC News 2021.
2. Campbell H. Experts cool claims about impact of vaccines on menstrual cycles. Euronews 2021.
3. HuffPost UK. What to do if your period is bad after your COVID-19 vaccine. HuffPost UK 2021.
4. Haaretz. Some vaccinated Israeli women report irregular menstrual cycles, bleeding. Israel News, Haaretz.com 2021.
5. European Medicines Agency. Safety of COVID-19 vaccines. European Medicines Agency. Amsterdam; 2021.