Re: 7m old sleeping 12hrs at night = supply issue??
As long as you feed on demand, your baby sleeping through the night will not cause you to lose your milk supply. Your body is smart- it rapidly figures out how to make the right amount of milk to meet the demand at a given time of day.
Often a mom whose baby is sleeping through notices increased nursing frequency during the daytime as the baby adds nursing sessions in order to make up for the nighttime ones he is missing. And that increased demand can leave you feeling really drained, at least until your body figures out the new schedule.
Personally, I see no reason why you should pump while your baby sleeps. But aside from lost sleep, there's no harm in doing it if you want to.
Coolest thing my big girl said recently: "How can you tell the world is moving when you are standing on it?"
Coolest thing my little girl sang recently: "I love dat one-two pupples!"