I'd be pretty surprised if that was true. There are definitely other reasons to take it easy and be sensible with what you do while pregnant.

Why not ask your doctor/midwife next time you see them to give you peace of mind? Then if it's not true, you can tell those people that your doctor said it's not true, and then they won't go about worrying people unnecessarily if it's not true.

Unless, of course, you don't want to hang the washing out, and then it's definitely true and you should be very careful.