Instruct: Classify Amazon reviews into positive or negative sentiment
Query: Poor Design

We have twin girls and were excited about the avent bottles that we had registered for. We received 32 bottles and have regretted registering for them ever sense. After following the directions, we have complaints about the nipple being a challenge for babies to get a grip on. A lot of the formula leaks out the side of their mouths while feeding them. This hasn't changed in 9 weeks, I don't believe they will adapt to them. Gerber bottles have worked great