Is the phase of the menstrual cycle relevant when getting the covid-19 vaccine?

Stability of the menstrual cycle is a key indicator of health, and its alteration can affect the physical, emotional, sexual, and social aspects of menstruating individuals¿ lives. A recently published study showed a statistically significant increase in cycle length after vaccination against COVID-19 and no significant changes in the menses length. However, there is no information about the potential association between vaccination time and change in cycle length. This study aims at assessing the association between the phase of the menstrual cycle at vaccination time and change in cycle length.