The large amounts of antioxidants in green tea are not good for baby as they can cause spinal malformation. However the spine is fully developed now. I would suggest Earl Gray tea or jasmine tea, peppermint, hot water with lemon and honey is best for your cold. Feel better. Lots of rest and fluids
green tea has a LOT of caffeine in it..your average cup has 40-75mg of caffeine , whereas your average soda has 30-50...so that's something to keep an eye on.
green tea also blocks the body's absorption of folic acid and iron, so it's something you want to drink in moderation. It IS great for you and has many antioxidant properties...so it's good to drink a little. but like most things in pregnancy...moderation seems to be the key :-).
Be careful with your herbal teas, not all of them are safe while pregnant. I use peppermint tea with some lemon...also very great combination for a cold. :)
if you can get them, the camomile and spearmint one is good, I put honey in it and it helps relax you, especially good to have a couple of cups before bedtime :)
I dont know why you have heard that about green t, the only reason I could think of would be the caffine in it, I have herbal tá and sweeten them with honey, you could try a herbal lemon t, or we get a lemon and ginger one over here, twinnings make a good range of herbal teas that you could try