Common side effects of covid-19 vaccination listed by the UK’s Medicines and Healthcare Products Regulatory Agency (MHRA) include a sore arm, fever, fatigue, and myalgia. 1 Changes to periods and unexpected vaginal bleeding are not listed, but primary care clinicians and those working in reproductive health are increasingly approached by people who have experienced these events shortly after vaccination. More than 30 000 reports of these events had been made to MHRA’s yellow card surveillance scheme for adverse drug reactions by 2 September 2021, across all covid-19 vaccines currently offered. 1

Most people who report a change to their period after vaccination find that it returns to normal the following cycle and, importantly, there is no evidence that covid-19 vaccination adversely affects fertility. In clinical trials, unintended pregnancies occurred at similar rates in vaccinated and unvaccinated groups. 2 In assisted reproduction clinics, fertility measures and pregnancy rates are similar in vaccinated and unvaccinated patients. 3 4 5 6