I'm EBF, and my baby cosleeps with us. She feeds pretty regularly through the night, usually 3 times, but they aren't full feedings. About once or twice a week she sleeps a really long stretch for about 6-7 hours, even 8 hours, so much that I wake up with a very engorged breast (one side produces much more milk, the other side doesn't seem to fill up like that) because she has slept so long. During that long stretch she might nurse for a few minutes here and there, but nowhere near enough to make a dent in the amount of milk.
She empties the over-full side in the morning, but if she started to sleep that long each night, would it hurt my supply in any way? She's 3.5 months, so we have a long way to go! I'm assuming as long as she is emptying it in the morning there shouldn't be an issue?