yep, multiples = high risk.
depends on type of twins - what risks the babies are at.
plus higher chance of being premature.
and then with mum, higher risk of gestational diabetes, high blood pressure, pre eclampsia etc..

mums pregnant with multiples can still have relativly 'uncomplicated' pregnancies, but they are just have a higher chance of things. I think the main thing is risks to the babies though.