My 3.5 month daughter sleeps pretty well, with some self-soothing in the night (though her napping is pretty rubbish). She sleeps best when tightly swaddled. Due to her being a houdini, we use this zip-up swaddle which contains her nicely: www.ergopouch.co.uk/products/swaddles-and-wraps/ergococoon
We have both the 1 tog and 0.2 tog. The 1 tog is much more confining and we use it every night with a single blanket on top. The 0.2 tog is much stretchier (and we've had it longer, so it may have stretched through use) and she has greater range of movement and so sleeps less soundly.
All good - until last night when the zip on the 1 tog broke 45 minutes after bedtime. Cue upset baby. She slept in her 0.2 tog swaddle with a warmer blanket, but woke every 1-2 hours needing soothing. It's obviously too loose for her.
My question is whether it would be OK to wrap swaddle her in a light bamboo sheet, and then place her in the 0.2 tog zip swaddle? It would probably confine her enough to get a good night's sleep, but I'm unsure about overheating/what other blankets would be required. She sleeps in her own crib and the temperature is generally around 18*C.