All my babies tummy slept from day 1. I know that SIDS guidelines rule against this but my babies would just NOT back sleep. They could all hold their heads soon after birth. I followed all the other SIDS guidelines and made sure the mattress was firm, we didn't smoke, didn't use bumpers on the cots etc. I didn't swaddle or use sleeping bags. By the time I had my 3rd baby a paed told me that it often runs in families that babies prefer tummy sleeping.... it obviously runs in ours! The paed observed how well my baby was able to hold his head up whilst on his tummy so quietly gave me the "go ahead" to let him sleep that way.

In the past most babies were placed on their tummies because the "experts" said that they could choke on their vomit if they slept on their backs. These things are always changing. If you are deeply concerned then ask a MCHN about the frequency of babies preferring to tummy sleep. Mine said that about 1 in 10 would only tummy sleep.

Make sure that there are no potential obstructions or entanglements. Make sure the mattress is firm. Personally i wouldn't stress, especially if your baby is able to hold his head up when on his tummy.