COVID-19 vaccines, including adenovirus vector vaccines (such as those authorized for use in the United States and Canada), subunit vaccines, and mRNA vaccines, have not been found to significantly impact the menstrual cycle. - Anecdotal reports of temporary menstrual changes following vaccination have been noted, but these changes are considered minimal and temporary. - Vaccines have not previously been associated with menstrual disturbances. - Environmental stresses can impact menstruation, but there is no evidence to suggest that COVID-19 vaccines specifically cause significant or long-term disruptions to the menstrual cycle. – The available data from retrospective analyses and meta-analyses indicate that any effect of COVID-19 vaccines on menstruation is intermittent and self-limiting. - Menstrual irregularities, such as changes in flow, have been reported but are considered minimal and temporary. - Individualized counseling may be suggested for patients who already have menstrual irregularities or fertility issues until more data from prospective cohort studies become available. - Clinical pregnancy rates, sustained implantation rates, egg quality, embryo quality and development, and pregnancy rates are not impaired following COVID-19 vaccination. The number of vaccine doses (1 or 2) and the time interval between vaccination and embryo transfer do not influence study outcomes related to fertility or IVF success. - There is no scientific evidence to suggest that any FDA-approved or FDA-authorized COVID-19 vaccines (including Moderna, Pfizer-BioNTech, Janssen) affect current or future fertility in women. Infertility is also not known to occur as a result of natural COVID-19 infection. The data shows that between COVID-19 vaccination and menstrual function beyond a short delay of one day in the first cycle following each dose and an equally short-lived increase in the prevalence of long cycles. Both of these changes disappeared by the second cycle post-vaccination, and the temporary effect is probably due to immune system activation, mediated by cytokines that interfere with the hypothalamus-pituitary-ovarian (HPO) axis.
Ref:
https://www.sciencedirect.com/science/article/pii/S0264410X23006813 
