Hi there

I've just been reading up on this myself and the NSW Health recommends no more than 200mg of caffeine per day (some other sites say 300mg).

They say this is a maximum of 4 cups of medium-strength tea per day. If I remember the Twinings box correctly, English Breakfast is regarded as a medium-strength tea, so four cups it is!

http://www.foodauthority.nsw.gov.au/...y-brochure.pdf

Happy pregnancy!