Re: Not getting enough when breastfeeding
Welcome to the forum!
I think the first thing to concentrate on is just how far you have come! Your baby was born so early, and yet she is home, able to nurse, and getting a lot of her nutritional needs met by you. Those are huge achievements, really!
At 3 weeks, many term babies are still struggling to master breastfeeding. And they may not be ready to nurse without the shield if their moms have been using one. I think right now you should probably resign yourself to the shield. Keep offering the bare breast, of course, but don't feel like it's some sort of huge failure if your baby isn't ready to nurse that way yet. Just put the shield back on and try again later.
Shields are great for babies who have difficulty latching without them. The big problem with shields is that they can reduce stimulation to and milk removal from the breast, and that can result in lowered supply. It's possible that the shield is all or part of the reason you have been unable to get a full supply, or to meet your baby's need solely by nursing.
Another possible complication is that babies who get lots of bottles from very early on often become rather lazy at the breast. They know they can nurse without too much effort, and yet still get their needs met by the bottle. The way to deal with this is to either eliminate the bottles. You can slowly decrease the amount you supplement, watch diaper output and weight gain carefully, and hope that a hungrier baby will nurse more and more enthusiastically, bringing your supply up. Or you can choose to supplement without using a bottle- using a Lact-Aid or Supplemental Nursing System might be really helpful to you.
Since your baby is currently nursing so infrequently, pumping is going to be part of your life if you want to meet more of her nutritional needs with the breast. Pumping shouldn't make you sore, so I would make sure that you have the right size of breast shields. Improperly sized shields might also explain why you're having trouble producing enough, and why it takes so long to get enough milk. I'd definitely consider going back to the hospital-grade pump for now, as well- you never know if it might help.
How often are you currently pumping?
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