OK. You’re having a baby, and you want to carry your own really good water that you’ve checked out and love a lot. It comes in a plastic bottle, however, and the plastic composition of polycarbonate water bottles includes bisphenol-A (BPA), a potent chemical that mimics the estrogen hormone in the body, risking impairment of the reproductive tissues and organs in both males and females—especially before they are born. BPA has been found in the blood of pregnant women, within the placenta, and in umbilical cord blood.1
Studies have recorded the leaching of this chemical from the polycarbonate bottle into the water when the bottle is frozen, heated, at room temperature, damaged, worn, reused, and so on.2 The bottom line is that there are questions about the safety of any kind of polycarbonate plastic container under any condition. PVC and styrene plastics are also known to leach harmful chemicals.
My advice is to minimize eating or drinking from plastics with the recycling numbers 3, 6, or 7 whenever possible. If you use plastic bottles, opt for those with the symbols 1, 2, 4, or 5. This is consistent with the recommendations of the Mount Sinai Medical Center and the Food and Health Program of the Institute for Agriculture and Trade Policy. Or better yet, trade in your plastic bottle for a lightweight stainless steel water bottle—they’re easy to carry, durable, and can be washed either by hand or in a dishwasher.