Yep, I have it on prescription. This is my fourth baby (sixth pregnancy that has got beyond 6 weeks and into "symptoms" territory) and for the first time ever.. hello massive heartburn.
I'd heard about people having heartburn in pregnancy before, and just thought "oh, chew on some Rennies" or "drink less orange juice".. okay, maybe not quite that flippant, but I had no idea of just how horrific proper pregnancy heartburn is. Quite another thing entirely to what you get after eating something spicy, that's for sure.
When the Rennies didn't work, the behind-the-counter extra strength liquid Gaviscon didn't work, the rantidine didn't work, and I was dying 24/7 it was time to go to the GP. He prescribed it for me over the phone instantly, and I picked it up half an hour later. It's amazing stuff, isn't it? My heartburn is 99% gone.
I've been on it since 7 weeks (am now 11 weeks) and suspect I will be on it for the duration, as when I've tried missing a pill to see if it's gone, it's still very much there. Unlike most of my other symptoms which have mostly gone now.
I did a lot of research before begging my GP and came to the conclusion it was almost certainly fine, and the benefits outweighed the risks. When you're talking your sanity, ability to sleep and even corrosion from the acid, it matters. For the record, in the US it is known as Prilosec so you may be able to find out more research by searching by that name too.
Good luck. I can't believe how much it helped me. If only there was a pill for nausea/puking that was as efficient!