you'll have the option of having the triple screen to test your baby for birth defects. or, the odds of your baby having birth defects. i opted not to have it, because i didn't want to be paranoid for no reason & it wouldn't make a difference, anway. i'll love my son even if he were to have any defects.
you'll have to get a glucose screening test when you're around 28wks. they take blood, then make you drink a suuuuper sugary drink, & then take blood again. it's to test for gestational diabetes.
when you're aroung 36wks, you'll probably get tested for group b strep. it's like a pap smear, kind of. & .depending on your doctor, they might to start to check you to see if you're dilated around this time, too. but with that, they just shove a few fingers way up there & that's that.
the "needle" thing you're talking about is an amniocentesis, & there's no real need for that unless they find something really abnormal. there is a very very very slight risk. & .having one done is definitely not mandatory.