When can I start pumping?

When can I start pumping and use both the bottle and my breast to feed my girl? I am still using a nipple shield because I have flat nipples, and I think this will be a long term thing.

I had to use a shield the whole year I breastfed my daughter and I’m sure I will again after I have my son. I started pumping a week or so after my milk came in so I could get a stock pile started for when I went back to work after my maternity leave was done. They suggest waiting until baby is 4 weeks old before introducing a bottle to avoid nipple confusion