oh and also we were told as well if you are attempting breastfeed to avoid the wide necked bottles as it is false advertising, they might look closer to nature but when in the mouth they are aren't. Also avoid BPA at all costs which means avoiding most of the Avent bottles (although they are phasing their BPA out but please check the bottle you are buying to make sure, don't assume it is BPA free).
And our Dr. Browns bottles fit the medela breast pump as will most narrow necked bottles.