I was moderately aware of BPA (thanks mom) when we started doing the bottle thing with the Sprout. However, I was more interested in getting her to eat from a bottle, since it wasn't going really well. However, the outlook has gotten worse.
I have a picky daughter. She thinks breasts come with silicon covers and that artificial things to suck on involve odd "orthodontic" shapes. No information I could find on the Internets (here, here and in open questions to the LLL crowd) helped me out with my particular issue. So I've spent some money and done some research.
Nuk wide mouth nipples do not fit on any bottle that I could find. Their bottles are just slightly smaller than most other wide mouth bottles. German manufacturer Nuk does make a wide mouth glass bottle, but I was unable to find a way to purchase it. Even if I found it, we only use bottles for daycare, and I think the chances of them wanting to use a glass bottle are... none.
Nuk "standard" nipples are orthodontic in shape and fit BPA free bottles that are readily available including Gerber, Medela, etc. They offer something no other "standard" nipple has, venting. However, if you are looking for a bottle that has the "breast like" wide base and the orthodontic shape, there doesn't appear to be a bpa free alternative. (we did try the narrow one, but she likes to "latch" on to the bottle and get in to her normal sucking rhythm, can't do that on a narrow nipple)
BPA free alternatives with "natural" shaped nipples: (though seriously, my nipple has never looked like that)
Born Free - Wow are they expensive. Pretty much anyone researching stuff knows about them, I won't waste the space.
Gerber GentleFlow - There seems to be a lot of love for the Avent bottles among breastfed babies (mine just wasn't one of them). These are nearly identical. The nipples don't have the same extra outside sealing ridge that Avent does. However, their nipples are completely interchangeable with the Avent nipples. Had the Sprout liked the Avent bottles, we would be going this route. They weren't available at any major big box retailer that I found, but I found them at a Walgreen's and they are available on their website.
Playtex Drop Ins - Here is where it gets interesting. There are two kinds of bottle liners from Playtex. The stiff ridged "drop in", and a plain plastic bag. The stiff ones work on Playtex bottles only as far as I can tell. The bags, though I haven't tested it with milk, would appear to work on just about anything. I'm sure Playtex wouldn't recommend that however. I have yet to feed with this option because I'm not sure what it would do with a venting nipple. The bottle frames (that makes sense right?) from Playtex come in two different varieties, Original, and Premium. The Premium is Polycarbonate (and thus has bpa), the original is not. You're not actually having liquid touch the frame with the premium, but why encourage them. Downside, heating up stuff in the liners. Of course, you wouldn't microwave breast milk, but if you're thinking you'll use your bottle warmer, I don't think they'll work. I can't confirm that, but I'm extrapolating from their literature. If you heat under hot water, they're good.
What I'm going to do.
I'm going to try the bag type liners (note: they say you can store bm in them, oh are they delusional) in my wide mouth Nuk bottles, see if it heats up ok, and see if daycare is cool with them. Right now the Sprout won't take any other kind of nipple. Doesn't mean I wont' keep trying. I'll be careful about my bottles, avoid the dishwasher, etc. I'll also transition her to a sippy cup earlier rather than later. There are SO many more sippy cup options.
