Hello blackpip
I can identify with that. It took 13 years to get pregnant with my first son and I couldn't really relax till about 28 weeks, when, at that time (25 years ago!!), it was considered the stage at which even if baby came he/she would survive.
Every miniscule twinge would worry me and I would have my nose permanantly in baby books (no internet then).
Gradually as time went on it got a little better but I had a very busy job that I didn't leave until about 30 weeks.
That is the only answer - diversionary tactics.
Good luck to her.