Should I tell new job I'm pregnant

I'm 14weeks and 3 days pregnant. My current workplace know and have been very supportive to my needs. I've just signed up with a teaching agency to do some exam invigilating since I usually to this every year. They have already booked me in for a few shifts in May and beginning of June. Do you think I should tell them about the pregnancy? Or is it not that necessary seeing as I won't be working with them once exam season has finished. Any advice really appreciated. Thanks