How much milk do I need to express for a day's feeding?

[NoviceKnitter]

I'm want to feed my 8 week old LO expressed milk for 12 hours after a hosptial test this coming Friday that will leave a low risk substance (contrast dye) in my system for around that time.

I haven't started expressing yet. She averages out eating every two hours. How much milk should I express and is it realistic to expect to get enough for her by Friday afternoon? And is it over-ambitious to expect DD to manage around six feeds from a bottle for the first time?

It's probably ok for her to have my milk after the test but I'd prefer to protect her completely if possible... I guess if I can express some and top up from the breast that will be a good compromise.

Thanks for any advice.

From my limited experience with bf and expressing I could only express about 2oz (per breast) at a time at that point, but that was hand pump. I believe from what friends have told me that an electric pump is more efficient and a double one if possible. How many feeds per day does she have ? and night?

I'd start expressing now, don't panic but the more you have the more she will have. Have you considered formula if you don't manage to express enough?
Also, have you thought about expressing on the Friday so you are still demanding the feeds so it doesn't interfere too much with your supply?
Don't worry too much about the quantity you express, they may just be small amounts to begin with but they will soon add up.
I used to express a little & then add this to a bottle in the fridge. Milk left in the fridge will settle and look quite watery on the bottom with a creamy top, just shake it & it will be fine!
Good luck.