can someone explain PI measurements please?

[RockerMummy184]

Went for a scan today. Twins so 2 sets if measurements for everything.

When I looked at the PI measurement one was right at the bottom of the scale (0.8) the other was right at the top (1.2). Didn't end up seeing my consultant as the unit was short staffed due to annual leave, so couldn't ask about it.

Does anyone have any idea what this reading means? What level is normal?

Following to see what answers you get, as far as I know it's something to do with blood flow through the arteries in the placenta.

I have consulted Google and apparently it stands for Pulsatility Index, but I can't seem to find anything that explains, in layman's terms, what it actually means, or what is 'normal', or what effect it can have.

I am interested to know if there is any link to fetal growth, since both twins have been growing at an almost identical rate so far and the PI reading has been very similar on other scans, but this time there's this large difference in the PI and one of the twins is now larger than the other.

I'm not sure about low measurements, but high can be a problem. Mine were both off the scale at my 20 week scan. The baby was fine then but later growth slowed and they decided she needed to come out at 34 weeks, after several weeks of very close monitoring. She was tiny but fine. It doesn't sound like you are in that area though, if you are only at the top end of the normal range on one side. It's all about the pressure of the blood flow through the uterine arteries and onto the umbilical cord.

In my case there was a definite link to foetal growth. No doubt with twins they will monitor you well anyway.