Lots of IVF specialists monitor uterine blood flow during an IVF cycle. They believe that this helps them to track uterine receptivity, and good flow correlates with implantation rates. This makes logical sense, which is why so many sonographers study uterine blood flow doppler wave forms and the PI ( pulsatility index)
I think this is meaningless.
The fact that the endometrium is growing to a thickness of 8 mm means that it is receiving adequate perfusion - how would it be able to grow without an adequate blood supply ?
This is another one of those measurements which are of no clinical value - but are done simply because we have the technology to do it !