Mine were 36+5. All along the OB was telling me I'd be lucky to make 30 weeks and in the end, I had to beg him to induce me coz I was so over being sick. He wanted me to try and hold out til 38 weeks but I was literally at the stage where one more day with them inside me seemed impossible to cope with. I spent the last month on bedrest as I was pretty much too huge to move and the circulation in my legs was suffering from having giant babies pressing on my arteries etc. We were lucky, my girls were both head down and I was able to deliver them both vaginally with no intervention other than the pitocin to kick things off. And they were 6lb8oz and 7lb1oz so epic weights for their gestation, and didn't need any time in special care/NICU.
This is a weekly guide I wrote with help from our consultant OB so might give you some ideas what to expect. I'm sure all the testing etc. is on a slightly different schedule in the States, but the babies still grow the same lol! http://www.ohbaby.co.nz/pregnancy/twins ... kly-guide/
And this is some info on zygosity and chorionicity, it can be a bit confusing initially but basically zygocity determines identical vs frat, and chorionicity is the number of placentas. http://www.ohbaby.co.nz/pregnancy/twins ... /zygosity/http://www.ohbaby.co.nz/pregnancy/twins ... rionicity/
And just for fun, some stuff on the quirkier aspects of twins... http://www.ohbaby.co.nz/baby/twins/its-a-twin-thing/
Hope that helps! We also joined our local Multiple Birth Club while I was still pregnant and they were a great source of support. Lots of other HG mummies there too with it being more prevalent in twin pregnancies.
DD 28/02/03 HG 8-20 weeks
MCDA twin DDs 14/10/06 HG 6 weeks - delivery via induction at 36+5
DD 09/07/08 HG 6 weeks - delivery via scheduled induction at 38 weeks due to HG
DD 18/06/12 HG 6 weeks - delivery via scheduled induction at 38 weeks due to HG
"I have died every day waiting for you, darling don't be afraid, I have loved you for a thousand years and I'll love you for a thousand more."