Our 4 week old DS tends to suffer from wind and what we think might be reflux. The advice we've had is to keep him sat upright for 40 mins - 1 hour after each feed. So far, we've been doing this by just holding him and it works OK but our biggest problem is getting him down to sleep. If we put him into his car seat or hold him in a baby sling, he sleeps perfectly well but as soon as we try and transfer him to the Moses basket / crib and lie him flat, he wakes up again within minutes and can't settle at all. If we put him lying flat on his back, his feed repeats on him and he gets hiccups and starts to spit up his feed. This happens anytime we lay him flat. If, for example, we need to change him after feeding him and lay him flat on the changing table to do that, he is almost guaranteed to spit up or even vomit his feed.
So what I want to know is, is it safe to allow a newborn to sleep sitting upright e.g. in a car seat? Our car seat is Jane Matrix so can be laid flat as well as in a sitting-up position. It's just that all the advice on SIDS is to have young babies only sleeping flat on their backs so we're worried to allow him to sleep unsupervised anywhere other than lying flat in his Moses basket.