You should be just fine just be safe no crazy driving out there! I was jumping off bridges when I was pregnant with my son and he is perfectly healthy. Y'all have fun!
With #1 I drove my own bike until my third trimester cuz it got all winter monthy and I got huuuuge so I couldn't sit comfy :)
Thanks ladies ;) were always careful :)
In theory you're good to go, but please be careful! I know so many people who have been seriously injured on bikes of all sorts.
As long as he drives safely then you should be fine until you get uncomfortable riding