You can’t say “I have a newborn, so I don’t sleep”. You still decide to use the other hours in the day for other things than nurturing the baby.
And you must plan that, it’s ultimately your responsibility to decide and act on this. The fact that you’re owner of everything in your life.
To me, this responsibility is very relevant, I know some healthy habits (eat, sleep, meditate) loosen up when I sleep less and drink more coffee. And then a vicious circle of bad behaviour (habit) starts as easy as it is hard to break through the habit.
Ultimately it’s not the baby deciding that I let this happen, it’s me.