My understanding follows. I have no research to back it up.

There is a 90degree angle from the teat to the base inside the bottle nipple. It can injure mom's nipple to have it forcefully and repeatedly pulled against that edge.
Baby's compression is on the teat and not on any "areola" area on the bottle nipple, so baby bites on mom's nipple with every suck or compression. That can cause injury to mom's nipple.
The holes are tiny on the bottle nipple. Not so tiny that great volumes of liquid can't pass thru, but when one thinks of the risk of aspiration and baby's ability to draw air thru it if it gets lodged in baby's throat, well....
It works solely on suction, and not a bit on compression. Any tongue massage action is on the teat and not on mom's areola. Initially, baby may get good milk, but over time, incomplete milk removal can lead to reduced supply.

The silicone nipple shield is formed to eliminate that 90degree angle on mom's breast. It allows babe to open wide and do compressions on mom's areola instead of the end of her nipple - if applied properly. The holes are much larger, in theory to allow air to pass should babe get it lodge in the throat. You still miss the areola massage by the tongue, but it's a great improvement over using a bottle teat.

I have NO financial interest in any of these products. Just my observation of moms using both. Thank goodness I have never seen a baby aspirating either device. But I have heard of the risk.

Phyllis

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Phyllis Adamson, BA, IBCLC
Glendale, AZ.
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