My youngest son had sleep apnea when he was your daughter's age. I did not know what it was until he was about 3 years old. A few questions that might help you to understand if she has it or not... Does she roll over on her stomach or side to sleep every night, even if you lay her on her back? Does she make this sound every night, several times a night or snores every night? Has she recently had a cold or sniffly nose? Is she eating properly and growing normally? Does she run and play with other kids with out getting tired or running out of steam quickly? I am just asking based on my own experience. My son exhibited all of these things because he wasn't breathing properly, especially at night. My son would roll onto his stomach every night to sleep since the first day he was born. It used to drive me insane because I thought he would die of SIDS like that, but come to find out, that was the only way he could breathe! It turned out that my son's adenoids were blocking his air passage way to his nose. When I put him to bed on his back, it compounded the problem- almost completely shutting his airways. (He used to sound like a buzz saw when he slept.) After he had them removed there was no more problems with him not breathing when he slept. I think that if she is consistently making these noises every night, I would have her checked by her doctor. It might just be a simple post nasal drip that caused it, it could have been a fluke, or it could be something serious like an obstruction that causes apnea. I would keep a diary of every time that you notice it happening. If you see a pattern, then it is time to bring her in for a check up. If she is truly having sleep apnea, you will definitely see a pattern. Good luck to you! C.