Is it OK to let my 10-week-old daughter sleep through the night in her infant chair?

My daughter is 10 weeks old and since about 4 weeks old has slept most comfortably in her infant carrier seat. She sleeps pretty much through the night or wakes up only once, then falls straight back to sleep. We recently tried putting her in her cot to sleep. She now wakes up about every hour or two and has difficulty getting back to sleep. Is it medically unwise to allow her to sleep in the infant carrier seat?

It is fine for her to sleep in a semi-upright position, but she will soon outgrow the seat. She'll be big enough to tip it over, roll out of it or wriggle and get tangled up in the straps. So it's probably wise to solve the problem in another way. She most likely responded well to the snuggly, contained feeling of the seat while the more open cot allows her to wriggle too much. Wrap her up in a lightweight blanket with her hands up by her face. Put her at one end of the cot next to well-attached bumper pads. Make sure she is on her back, on firm bedding, with no pillows or fluffy bedding around. Another part of this "problem" may be that she is now at the stage of brain development when her sleep is more easily interrupted; earlier her sleep was more determined by her own internal regulation. So she may be going through a change that has nothing to do with where she sleeps. With your support, she'll get into a new, more mature sleep pattern.