Amniotic fluid @ 33 weeks was 22cm. ob didn't discuss with me. i saw u/s report. should she have told me? would this cause pre term labour @ 35 wks?

Polyhydramnios?: There are two ways that the fluid can be reported. One is maximum vertical pocket and the other way is afi, or amniotic fluid index. The latter is more common and, assuming it was your afi that was 22 cm, that is at the upper limit of normal (up to 24-25 is considered to be normal). Also, 33 weeks is the point in pregnancy where the fluid volume is usually at its highest.