Hi Jenn,

I don't think it was a mistake having him sleep with you as a baby, little babies thrive on physical contact with you and he has likely reaped many developmental benefits from it.

I saw a fascinating documentary several years ago that monitored babies' biological rhythms when alone in a room, vs. when a parent walks in, vs. when an unrelated person walks in. Turns out that in all cases, babies somehow negotiate their biological rhythms (heartbeat, etc.) to be in sync with a parents, while this does not happen when someone else enters the room. This effect is especially strong in physical contact. While these are unconscious processes, their little bodies and brains are still very new at being responsible for themselves, and these rhythms are probably learned more quickly and smoothly by example (as with anything else). Anyway...

My son slept with me while he was a little baby, though at about 6 months or so I started moving him to the crib once he was asleep (the crib was right beside our bed, too, which helped). He would wake up at some point in the wee hours for some milk and so we'd fall asleep together in the bed again until morning. This was just to get him used to the crib, and I'd recommend you keep that up with your son for maybe another month given your 4-month time frame here... it's tight but I think you can get some reasonable results this way. My son was about 12 months when we started insisting that he stay in the crib, so we're talking about the same age.

If he wakes up in the middle of the night, bring him to the bed with you FOR NOW. When it's been about a month of that, the crib will be familiar enough to him that you can start insisting he stay in it to sleep if he wakes up, but you can still put him to sleep in your bed initially. When he wakes up, offer him some warm milk, hold him and rock him for a little while, then gently put him back in the crib and tuck him in. Rub his back or his tummy, sing to him softly, whatever helps. When he pushes himself up, pick him up briefly, hold him, rock him, then put him back in the crib again. This makes a point that you will comfort him, but he needs to sleep HERE and that is that. Having one of those wind-up music boxes can be a helpful distraction (it won't work immediately but will help later by familiarity if you put it on consistently). My son had a stuffed lamb that played "Mary had a little lamb". It served a double purpose as being cuddly.

He will cry for the first while. You will have some long rough nights of getting up with him. BUT ALWAYS PUT HIM BACK IN THE CRIB. Make sure needs are met, but be consistent. The instant you take him back to bed with you once this process has started, you undo all your good work so far. Look after his physical and emotional needs but always put him back. It will slowly sink in, so just be consistent and patient. At least a month before the new baby is expected, start putting him to sleep straight in the crib. Follow the same bedtime routine as you always have, only put him in the crib instead of your bed. Deal with any protests the same as you have for mid-night wakings.

Most importantly, involve him when you spend time with new baby on your bed during the day, so that he doesn't feel resentful of this new little person stealing his favorite spot. My son & I would have story time in my bed and then warm milk and a lullabye in his crib. Make sure he gets some one-on-one time with you like this before bed.

Good luck!