[alaithea]

There seem to be differing opinions on that. A bit of a Googling suggests that you wait until the cord has stopped pulsing, which might be as soon as a few minutes.

I'm not sure why the risk of infection would increase with the cord intact versus it being cut (where germs could potentially get in anyway). The baby's and mother's blood don't mix, so even if there were a "wound" on the placenta where it came unattached, that would be on the mother's side.