There are two parts to this discussion.  
One is access.  Not everyone has close access to a Lactation Consultant.  In a perfect world nipple shields would only be given by someone trained to educate the mom in how to use and care for the nipple shield.  But that is not always the case.  When I speak to a mom on the phone who is ready to give up because she can't get the baby to latch is it better for her to switch to formula or use a shield.  Yes, she should come in and be assessed but if she lives two hours away it is not possible.  Not everyone lives close to breastfeeding clinics to obtain advice or products.  If I can help a mom keep breastfeeding by having nipple shields available at Target then I can live with that.  This is true of so many aspects of breastfeeding.  What about pumps or bras should they not be in stores or only in places that have Lactation Consultants.  I can't tell you how much trouble I have with bras with thick stiff padding in them or sleep sacks!
The second part is the size.  I use the extra small size only a few times a year.  I instruct my patients and other staff to use the size that fits the moms nipple without causing pinching.  If we use too small of a nipple shield we can cause damage, soreness and limit milk intake. 
I think the bigger issue is using the nipple shield at all.  I still hear conflict between nipple shields causing  or not causing decreased milk intake and production.  I must be behind in my reading because I thought that there was research that indicated that nipple shields did not decrease milk production or intake.  
Thanks for listening.

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