I used these bags when I nursed my now-2-year-old and never had problems; I liked them the best out of all the bags I had tried. Now, however, I am using them with my 5-month-old and am having issues with leaking from the bottom seam! It is a horrible feeling to "lose" ounces of precious breastmilk because of unexpected leaking from the bag. I'm switching to Lansinoh bags.