What should one do if he is reciting kerias shema al ha’mitta before going to bed, but is concerned that he might get interrupted (e.g. the baby will wake up and he will need to attend to it) before he ends up falling asleep? Should he recite everything except for the bracha of HaMapil? Similarly, what should someone do in regards to kerias shema al ha’mitta if they are going to sleep for the night, but they have reason to suspect that it will be difficult to fall asleep (e.g. they are not feeling well)?
There is controversy if the bracha has to be said immediately prior to going to sleep, (as if the bracha is being said on the sleeping), or that the bracha is being said on the institution of sleep, and even if the person doesn’t fall asleep right away he should still say it. The M:B 139-3 says that it should be said right before falling asleep however many other poskim say that it can be said earlier. In your situation, where it is very possible that you will fall asleep right away and the baby will not wake you up now, and even when one is sick, they will fall asleep but it might take some time, you can say regularly, when you are ready to actually go to sleep.
Best wishes and get a good rest.
Pri Hasadeh 1-93, Hisorirus Teshuva 128, Taharas Yom Tov 13 pg. 188, Aruch Hashulchan 139-6, Margenisa Tava pg. 303, Emes L’yackov ftnt. 254, Shearim Hamitzuyanim B’halacha 71-4 (seif katan 2), Be’er Moshe 1-63, Tzitz Eliezer 7-27 (3), Birur Halacha O:CH 2-pg. 261. PIskei Teshuvos 139-3.