I use these bags to hold pumped breastmilk in the freezer. I have not had any problems with the bags' integrity holding up to various temperature conditions. I don’t, however, defrost the milk in the microwave, which is not recommended anyway (creates hot spots in milk), so I wouldn’t know how well the bags would do in that situation. I've only held frozen milk in these bags for about a month at a time before I would need to make a bottle for hubby to feed the baby. Breast milk can be frozen for up to 6 months, so I would need to do an experiment to see how well the bags holds up. My only concern is when pouring the milk from the bag into a bottle, I need to be careful of where the milk touches the non-sanitized part of the bag's opening. I tend to wash the opening flaps first before opening the bag. Lastly, knowing how much milk is being stored in the bag is better determined by a baby's bottle set on an even flat surface. The level read on the bottle is always different than the level read on the bag.

These bags are really sturdy and freeze flat. I've purchased other brands where the corners have been sharp and would rip though the gallon freezer bag I store them in but these don't do that and are great! I've purchased at least 30 boxes of these so far and will keep repurchasing :)

I always loved this milk bag since my first baby in 21’ but what i don’t like if i were to attach my breast pump with it (spectra) it widens the bag which when i put the milk bag laying flat down the milk comes out the side so i would have to use another bag other than that i always have love for it

I have tried about 5 different storage bags. This bag is by far the best bag I've tried. (I need to thank my buddy again for recommending this!). I love the double seal. I haven't had to worry about leakage with these. Plus, these bags TRULY freeze flat! Used in conjunction with a breast milk storage organizer, I am able to build a good supply for when I return to work AND leave room in my freezer for actual food.

Used this brand exclusively two years ago and loved the quality and how they were able to stand on their own. The new design to the bottom of the bag is so narrow and bad they are not able to stand own their own anymore. Have to look for a new brand to use now.

I have used these bags during two exclusively pumping journeys. they freeze flat and when filling them to 4oz, laying flat in the freezer, i can make a brick of 13 bags/ 52oz. i am a massive over supplier of over 100oz DAILY. So i go through a ton of bags. these have always been my favorite

This has been the trust beand of milk breast storage bags for me for the past 17 years. occasionally the perforations and complete cut through so it makes it annoying to remove the plastic piece you toss. but other than that I've never had a problem with leaks or rips

Theyre my go to breastmilk storage bag. The seal is tight. No leaks. The only issue is dont trust the measurements on the bag, measure the milk before pouring it in because its not accurate but thats with any milk storage bag. This brand claims it only holds 6 oz but i managed to fill it with 10 oz. Even with 10 oz there was still room and the bag held up after freezing.

I use this product to storage my breast milk in the freezer. I've tried this Lansinoh, the Medela pump and store, and the Babies R Us storage bags. Definitely the Lansinoh are the best. They have a good size and they really stay flat when you freeze them. It's easy to write the date, time, amount of milk, etc. on them. The material they are made with is the best so far. They are flexible, not to bulky and I can take the air out better than with the other brands.

I really like these bags. I have filled them with only a few milliliters up to 6 oz. None have ever broken or leaked. They served us well during my twin pregnancy and now during my baby boy’s breastfeeding journey (almost one year). I can recommend these.