COVID-19 Vaccines Linked to Changes in Menstrual Cycle Length, Study Finds

A study by Oregon Health & Science University found that COVID-19 vaccinations may lead to temporary changes in menstrual cycle length, with those vaccinated in the first half of their cycle more likely to experience such changes. The study, based on data from nearly 20,000 users of a birth control app, revealed a one-day increase in cycle length for those vaccinated in the follicular phase, which typically resolved in the following cycle. While the exact biological mechanism is still unknown, researchers emphasize that these changes are temporary and should not cause concern, but advise seeking guidance from a doctor if prolonged changes occur.