No—in fact I actually ask that if your milk is currently frozen, you allow it to fully thaw before shipping it. The condensation from the thawing bag can actually cause your packaging to tear which can lead to damaged or lost goods.   Because nobody is going to be consuming your breast milk I am not worried about spoilage. That being said, breast milk has many amazing properties which prevents it from spoiling very quickly. It will be just fine in the mail for a few days. Full shipping instructions will be emailed to you after your order has been placed.