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I have a 3-month-old child. My pediatrician told me that you shouldn't let a baby sleep through the night until she/he is at least 4 months old. Even if they are gaining weight.
But my little one from day one had a different opinion. I turn on my alarm clock to make sure I get up to feed him. But every once and a while I don't hear my alarm clock and I wake up feeling like the worst mother for letting him sleep 8 hours! He has been gaining weight perfectly, weighing about 13 lbs now. He takes just a few quick naps during the day and eats almost every hour-two during the day until his bedtime at 8-9pm. I feed him at 9pm and again at 1-2am and then at 5-6am. But last night I didn't wake at 2am but at 5:30, and this has happened a few times. I also have a 20-month-old who would sleep through the night from the first month.
Could it just be that my kids like to sleep during the night? And why can't we let them sleep that long? I grew up always hearing "Never wake a sleeping baby!" Did they just mean during their nap?