My lil one officially sleep on her tummy when she is 3½ mth. When she first started to turn on her back at night , I'll always turn her over if not I'll keep wake up and check on her. I think its best when you're confident knowing your lil one is strong enough to roll back or front, only you know your lil one best, trust your instinct.
Nw my lil one is 8mth 2wks, she seldom sleep on her back because when I put her to sleep on her back she will cry until I turn her over🤦🏻♀️. Most likely she is more comfortable sleeping on her tummy. This is my experience with my lil one. See which position makes your lil one most comfy.
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