Hot drinks are fine. Of course, everything in moderation, but I had tea, coffee, hot chocolate...

Caffeine is a diuretic, and I'd say that's the issue - that at a time you want to be really well hydrated, you don't want to be encouraging fluids to leave your body. And you don't want a cup of tea before bedtime and then be peeing even more during the night! Just make sure your teas and coffees and on top of your normal drinks (and you should be drinking quite a bit of non-caffeine things to stay well hydrated), and not instead of normal drinks.

Most people won't have to change their tea/coffee habits anyway, if you're a one or two a day kind of person. If you have a coffee or tea every hour, or a super strong coffee in the morning though - then you'd have to reassess your drinks for the duration of pregnancy and early breastfeeding.