Women who found their menstrual cycle changed after having their Covid-19 vaccinations will be relieved to know thousands of other women also experienced this. A new study of more than 19,000 women has found that Covid-19 jabs are linked to a "small and likely to be temporary change in menstrual cycle length" and women who had two vaccines during the same menstrual cycle were the most affected.
Thousands of women had reported changes to their periods after having a Covid-19 vaccination - but this was not listed as a common side effect of the vaccine. Nevertheless, primary care clinicians and staff working in reproductive health were "increasingly approached" by people who experienced changes in their monthly cycle shortly after a vaccination, as reported by Dr Victoria Male, a lecturer in reproductive immunology at Imperial College London.
In an op-ed published in the British Medical Journal (BMJ) last September, Dr Male said more than 30,000 reports had been made to the UK Medicines and Healthcare Products Regulatory Agency (MHRA) by people who said their menstrual cycle had been affected by their Covid-19 vaccinations. Dr Male said this link was "plausible" and "should be investigated" - but also noted that the majority of people who reported changes to their menstrual cycle later reported that their cycle returned to normal on their next cycle. Importantly, Dr Male also noted that there was no evidence to suggest that Covid-19 vaccinations adversely affected fertility.
