Your fundal Height gives your midwives a general idea of the size of your baby by measuring the size of your uterus. It is to detect whether baby is growing at a good rate and size. 33cm is fine, your fundal height should measure around the same as how many weeks pregnant you are, eg' 36 weeks - 36cm. 2cm either side is fine...
Fundal height is generally what week you are. I say generally because it is NOT AN EXACT SCIENCE. The position of the baby, how much amniotic fluid you have, will all affect the size of your uterus.
That said, your fundal height is in line with your weeks. 33 cm @ 34 weeks is normal and average. They take fundal height to make sure to track what is going on in there in terms of too much growth or too little. It could mean you have too much or too little amniotic fluid. Or it could indicate twins if the weeks are far advanced. But this method of measuring only means more testing (ultrasound) would need to be done.
At my 9 week visit the doctor said that I had a tilted uterus and it was measuring at 9 weeks. I just went for my 13 week visit, and my doctor has said that now my fundal height is measuring at 16+ weeks. I was wondering if anything could be wrong? Maybe I've got two babies having a party down there.... I have an ultra sound for a week from now.. but it's so far away!!