The full flow period for IVF refers to the first day of your menstrual cycle when you experience a full menstrual flow, which is designated as day 1 and marks the beginning of the IVF process from a hormonal perspective.
According to the reference, Day 1 of your period, is the first day of your menstrual cycle. This is when the hormones reset to baseline, allowing the uterine lining to shed and prepare for a new lining to grow, which is essential for embryo implantation. For IVF purposes, the first day of full period flow is considered day 1.