Hey Mel,
CONGRATULATIONS

If you decide to go just for the US trip just prepare yourself for anything... bub may not have his/her routine for sleeping or eating sussed out so it may get a bit all over the place for them... all so the "jet lag" will play a little part in your bub possibly getting unsettled.
If you think you can handle the worst... which is probably only a fussy bub that doesnt sleep too well on your holiday then I say GO FOR IT MATE but if you dont think that you will be up for the lack of sleep and a fussy bub then maybe give it a miss.....

What a great oppurtunity... I totally understand your apprehension but!!

Thats a hard one mate

Good luck with your pregnancy and in your decision to go over seas!

xox