Dr. Browns Natural Flow Newborn Set

I bought the Dr. Brown newborn feeding set and those bottles worked perfectly fine for me. In fact, both my husband and mother in law preferred these bottles so much that I needed additional 4 oz bottles for them to use. However, every single bottle from this purchase has leaked while feeding. Even though we double check the seal to make sure everything is on straight and tight, the bottles always leak. In addition, the nipples that came with the bottles are not any definition of slow flow. After a frustrating night feed, I refilled the bottle with water and watched as it came out as a steady stream when tilted down or pressed. Oh, and it still leaked. Even if I was ok with wasting my limited amount of breastmilk, when your baby is fussing because s/he didn’t get enough and you have to warm up additional milk in the middle of the night so that s/he can go to sleep, it becomes unacceptable. UPDATE: I wanted to try to figure out why the new set of bottles leaked while the old ones didn’t, so I lined them all up to see if I can spot the parts that were part of my original two and the parts that were part of the new set of four I got. Long story short, I noticed some key differences, detailed below. I am not certain which of these differences is causing the leakage issue, but wanted to show them so others can check if they want to. I know there are other reviews that compare some of these parts, but I tried to take pictures of every component that was different. The most obvious difference is that my old set was made in China while the new one is stamped with USA (picture 1). I don’t know if this is due to Dr. Brown’s changing their production and the China sets are older/newer, but the USA bottles definitely are defective. The color of the straw is also different (picture 2). The USA set has darker straws that are also wider though it’s not obvious from the picture (I dry the straws on the pegs of my Munchkin rack and the lighter straw gets caught higher up on the peg while the darker straws sink lower). The nipple is also different (picture 3) - the USA set’s nipples have a flatter base (left in picture) and the China set has a wavy base (right in picture). Picture 4 shows the neck of the two bottles (the USA set on the right has more of a taper at the two ends of the threads) and picture 5 shows the ring (the USA set is on the right and the threads on the bottom seem to be a little further apart from the base). I wonder if the differences in the threads in both the neck and ring of the USA bottles cause the seal to be less than airtight. I should also point out that the China set was sent in a Dr. Brown packaged box while the USA set was sent in a plain brown cardboard box. Amazon is sending me a replacement set - we will see if they are the same bottles. If so, I will be returning again.