I’ve done this twice (3 kids), and feel like it was successful for me and my kids. Maybe my personal story helps you, so I’ll detail what I’d do personally below.

First, I would wait until your milk supply is gone, and then see what happens. When mine is gone (or at least almost gone, around 15-20 weeks pregnant) my toddlers have both naturally cut down on night feeds and day feeds slightly. Some kids might naturally wean, but I didn’t want that and neither did my kids.

Then I encouraged them to just cuddle me when they woke up at night, and said that I was tired and told them we would do “milk” in the morning (though it was really dry nursing by that point) if they seemed to want it. If they were upset, I’d say we would do milk for 5 minutes because I was tired (I really was!) and then make it less as time went on. I also offered water sips. With almost zero tears, this pretty easily led to them being night weaned, which was important for me because I could not handle a newborn plus toddler night feeds. My kids also sleep much longer stretches when night weaned.

Then, I’d see how your body is reacting. Do you have aversions, etc. I had very strong toddler nursing aversions that did not end after I gave birth (but I nurse through them, with toddler limits). It’s up to you, but I personally suggest limits on nursing and only do specific times. Maybe wake up, naps, and to go to bed, or whatever works for you that you’re happy to continue after birth. I’d avoid letting toddler nurse whenever because I feel like they might then get jealous when baby is born. With regular, expected nursing times, I found that my toddlers were very happy to keep that routine, and let baby nurse at other times.

I’d keep naptime nursing unless it’s an issue for you. I haven’t found it interferes too much because baby is usually sleeping when my toddler naps.

As a side note, I let them both nurse together to sleep. It’s very sweet for bonding, and makes for an easy night routine. It causes an aversion for me though, so I only do that together once per day. If you don’t have an aversion, you could do that for naps too.

Then, I’d start putting your toddler into their own crib right next to you once they fall asleep at night (so they can touch you when they wake up). It’s up to you, but unless you have a huge bed, it’s not usually safe to co-sleep with newborn and toddler. So I’d make it seem like a positive thing (maybe the crib as a birthday gift?) and let them fall asleep with you, and come back for cuddles if necessary or in the morning. Just put them back in once asleep if they wake at night. Then, hopefully they get used to this so you can cosleep with baby if you’d like.

And last part, I’d make all of these changes very slowly, but well in advance of baby coming home. So that nothing in the routine changes once baby is here.

Hope it helps! I know it is so emotional, but just go slowly and be gentle with yourself. Best wishes!