When to stop traveling for work?

Zana
Do any of you travel for work? I am a Pharmaceutical Sales Rep and have to drive 1.5-2.5 hours about twice a week and the rest of the week it's in my home town or 45 minutes away. Has anyone's OB discussed when they want them to stop traveling? I am nervous about it bc I don't want to be that far away from my OB after 28 weeks but my Manager is not taking it really well that I will not be able to travel. She has ever had a rep that was pregnant with twins and she doesn't understand that it's a little different