So most apps, sites and on/gym Drs say that they count from the first day of yourast period to determine how far along u are, but <a href="https://glowing.com/glow-fertility-program">IVF</a> dr states that technically it's about two weeks less than that because they go by actual transfer date. But if you look at the descriptions for starting from period it makes sense it includes ovulation fertilization blastocyst stage and so on so what is it??