I had really bad heartburn with Jenna from about 20w I spose? I managed it with rennies, then tums, then liquid gaviscon. That was wonderful!
It killed me, and even a glass of water repeated on me. I had asked my GP about heartburn early in the piece, and she had warned me off stronger meds - liek Zantac.
This time I have asked my midwife about heartburn, saying there was no way I was going to put up with it again this time. She said that it was fine for me to take Zantac, apparently the major side effect of heartburn medication is the disruption of iron absorbtion.
I have really good iron levels, so she said its fine to go on Zantac. I'll probably try and leave it til about 32w+ before I start them though. At the moment depending on my diet I can go 2 days without needing anything.

Some people say that milk helps heartburn.